target-arm: Convert TLS registers

[qemu.git] / target-arm / helper.c

#include "cpu.h"
#include "gdbstub.h"
#include "helper.h"
#include "host-utils.h"
#include "sysemu.h"

static int vfp_gdb_get_reg(CPUARMState *env, uint8_t *buf, int reg)
{
    int nregs;

    /* VFP data registers are always little-endian.  */
    nregs = arm_feature(env, ARM_FEATURE_VFP3) ? 32 : 16;
    if (reg < nregs) {
        stfq_le_p(buf, env->vfp.regs[reg]);
        return 8;
    }
    if (arm_feature(env, ARM_FEATURE_NEON)) {
        /* Aliases for Q regs.  */
        nregs += 16;
        if (reg < nregs) {
            stfq_le_p(buf, env->vfp.regs[(reg - 32) * 2]);
            stfq_le_p(buf + 8, env->vfp.regs[(reg - 32) * 2 + 1]);
            return 16;
        }
    }
    switch (reg - nregs) {
    case 0: stl_p(buf, env->vfp.xregs[ARM_VFP_FPSID]); return 4;
    case 1: stl_p(buf, env->vfp.xregs[ARM_VFP_FPSCR]); return 4;
    case 2: stl_p(buf, env->vfp.xregs[ARM_VFP_FPEXC]); return 4;
    }
    return 0;
}

static int vfp_gdb_set_reg(CPUARMState *env, uint8_t *buf, int reg)
{
    int nregs;

    nregs = arm_feature(env, ARM_FEATURE_VFP3) ? 32 : 16;
    if (reg < nregs) {
        env->vfp.regs[reg] = ldfq_le_p(buf);
        return 8;
    }
    if (arm_feature(env, ARM_FEATURE_NEON)) {
        nregs += 16;
        if (reg < nregs) {
            env->vfp.regs[(reg - 32) * 2] = ldfq_le_p(buf);
            env->vfp.regs[(reg - 32) * 2 + 1] = ldfq_le_p(buf + 8);
            return 16;
        }
    }
    switch (reg - nregs) {
    case 0: env->vfp.xregs[ARM_VFP_FPSID] = ldl_p(buf); return 4;
    case 1: env->vfp.xregs[ARM_VFP_FPSCR] = ldl_p(buf); return 4;
    case 2: env->vfp.xregs[ARM_VFP_FPEXC] = ldl_p(buf) & (1 << 30); return 4;
    }
    return 0;
}

static const ARMCPRegInfo cp_reginfo[] = {
    /* DBGDIDR: just RAZ. In particular this means the "debug architecture
     * version" bits will read as a reserved value, which should cause
     * Linux to not try to use the debug hardware.
     */
    { .name = "DBGDIDR", .cp = 14, .crn = 0, .crm = 0, .opc1 = 0, .opc2 = 0,
      .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = 0 },
    REGINFO_SENTINEL
};

static const ARMCPRegInfo not_v6_cp_reginfo[] = {
    /* Not all pre-v6 cores implemented this WFI, so this is slightly
     * over-broad.
     */
    { .name = "WFI_v5", .cp = 15, .crn = 7, .crm = 8, .opc1 = 0, .opc2 = 2,
      .access = PL1_W, .type = ARM_CP_WFI },
    REGINFO_SENTINEL
};

static const ARMCPRegInfo not_v7_cp_reginfo[] = {
    /* Standard v6 WFI (also used in some pre-v6 cores); not in v7 (which
     * is UNPREDICTABLE; we choose to NOP as most implementations do).
     */
    { .name = "WFI_v6", .cp = 15, .crn = 7, .crm = 0, .opc1 = 0, .opc2 = 4,
      .access = PL1_W, .type = ARM_CP_WFI },
    REGINFO_SENTINEL
};

static const ARMCPRegInfo v6_cp_reginfo[] = {
    /* prefetch by MVA in v6, NOP in v7 */
    { .name = "MVA_prefetch",
      .cp = 15, .crn = 7, .crm = 13, .opc1 = 0, .opc2 = 1,
      .access = PL1_W, .type = ARM_CP_NOP },
    { .name = "ISB", .cp = 15, .crn = 7, .crm = 5, .opc1 = 0, .opc2 = 4,
      .access = PL0_W, .type = ARM_CP_NOP },
    { .name = "ISB", .cp = 15, .crn = 7, .crm = 10, .opc1 = 0, .opc2 = 4,
      .access = PL0_W, .type = ARM_CP_NOP },
    { .name = "ISB", .cp = 15, .crn = 7, .crm = 10, .opc1 = 0, .opc2 = 5,
      .access = PL0_W, .type = ARM_CP_NOP },
    REGINFO_SENTINEL
};

static const ARMCPRegInfo v7_cp_reginfo[] = {
    /* DBGDRAR, DBGDSAR: always RAZ since we don't implement memory mapped
     * debug components
     */
    { .name = "DBGDRAR", .cp = 14, .crn = 1, .crm = 0, .opc1 = 0, .opc2 = 0,
      .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = 0 },
    { .name = "DBGDRAR", .cp = 14, .crn = 2, .crm = 0, .opc1 = 0, .opc2 = 0,
      .access = PL0_R, .type = ARM_CP_CONST, .resetvalue = 0 },
    /* the old v6 WFI, UNPREDICTABLE in v7 but we choose to NOP */
    { .name = "NOP", .cp = 15, .crn = 7, .crm = 0, .opc1 = 0, .opc2 = 4,
      .access = PL1_W, .type = ARM_CP_NOP },
    REGINFO_SENTINEL
};

static int teecr_write(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t value)
{
    value &= 1;
    env->teecr = value;
    return 0;
}

static int teehbr_read(CPUARMState *env, const ARMCPRegInfo *ri,
                       uint64_t *value)
{
    /* This is a helper function because the user access rights
     * depend on the value of the TEECR.
     */
    if (arm_current_pl(env) == 0 && (env->teecr & 1)) {
        return EXCP_UDEF;
    }
    *value = env->teehbr;
    return 0;
}

static int teehbr_write(CPUARMState *env, const ARMCPRegInfo *ri,
                        uint64_t value)
{
    if (arm_current_pl(env) == 0 && (env->teecr & 1)) {
        return EXCP_UDEF;
    }
    env->teehbr = value;
    return 0;
}

static const ARMCPRegInfo t2ee_cp_reginfo[] = {
    { .name = "TEECR", .cp = 14, .crn = 0, .crm = 0, .opc1 = 6, .opc2 = 0,
      .access = PL1_RW, .fieldoffset = offsetof(CPUARMState, teecr),
      .resetvalue = 0,
      .writefn = teecr_write },
    { .name = "TEEHBR", .cp = 14, .crn = 1, .crm = 0, .opc1 = 6, .opc2 = 0,
      .access = PL0_RW, .fieldoffset = offsetof(CPUARMState, teehbr),
      .resetvalue = 0,
      .readfn = teehbr_read, .writefn = teehbr_write },
    REGINFO_SENTINEL
};

static const ARMCPRegInfo v6k_cp_reginfo[] = {
    { .name = "TPIDRURW", .cp = 15, .crn = 13, .crm = 0, .opc1 = 0, .opc2 = 2,
      .access = PL0_RW,
      .fieldoffset = offsetof(CPUARMState, cp15.c13_tls1),
      .resetvalue = 0 },
    { .name = "TPIDRURO", .cp = 15, .crn = 13, .crm = 0, .opc1 = 0, .opc2 = 3,
      .access = PL0_R|PL1_W,
      .fieldoffset = offsetof(CPUARMState, cp15.c13_tls2),
      .resetvalue = 0 },
    { .name = "TPIDRPRW", .cp = 15, .crn = 13, .crm = 0, .opc1 = 0, .opc2 = 4,
      .access = PL1_RW,
      .fieldoffset = offsetof(CPUARMState, cp15.c13_tls3),
      .resetvalue = 0 },
    REGINFO_SENTINEL
};

void register_cp_regs_for_features(ARMCPU *cpu)
{
    /* Register all the coprocessor registers based on feature bits */
    CPUARMState *env = &cpu->env;
    if (arm_feature(env, ARM_FEATURE_M)) {
        /* M profile has no coprocessor registers */
        return;
    }

    define_arm_cp_regs(cpu, cp_reginfo);
    if (arm_feature(env, ARM_FEATURE_V6)) {
        define_arm_cp_regs(cpu, v6_cp_reginfo);
    } else {
        define_arm_cp_regs(cpu, not_v6_cp_reginfo);
    }
    if (arm_feature(env, ARM_FEATURE_V6K)) {
        define_arm_cp_regs(cpu, v6k_cp_reginfo);
    }
    if (arm_feature(env, ARM_FEATURE_V7)) {
        define_arm_cp_regs(cpu, v7_cp_reginfo);
    } else {
        define_arm_cp_regs(cpu, not_v7_cp_reginfo);
    }
    if (arm_feature(env, ARM_FEATURE_THUMB2EE)) {
        define_arm_cp_regs(cpu, t2ee_cp_reginfo);
    }
}

ARMCPU *cpu_arm_init(const char *cpu_model)
{
    ARMCPU *cpu;
    CPUARMState *env;
    static int inited = 0;

    if (!object_class_by_name(cpu_model)) {
        return NULL;
    }
    cpu = ARM_CPU(object_new(cpu_model));
    env = &cpu->env;
    env->cpu_model_str = cpu_model;
    arm_cpu_realize(cpu);

    if (tcg_enabled() && !inited) {
        inited = 1;
        arm_translate_init();
    }

    cpu_reset(CPU(cpu));
    if (arm_feature(env, ARM_FEATURE_NEON)) {
        gdb_register_coprocessor(env, vfp_gdb_get_reg, vfp_gdb_set_reg,
                                 51, "arm-neon.xml", 0);
    } else if (arm_feature(env, ARM_FEATURE_VFP3)) {
        gdb_register_coprocessor(env, vfp_gdb_get_reg, vfp_gdb_set_reg,
                                 35, "arm-vfp3.xml", 0);
    } else if (arm_feature(env, ARM_FEATURE_VFP)) {
        gdb_register_coprocessor(env, vfp_gdb_get_reg, vfp_gdb_set_reg,
                                 19, "arm-vfp.xml", 0);
    }
    qemu_init_vcpu(env);
    return cpu;
}

typedef struct ARMCPUListState {
    fprintf_function cpu_fprintf;
    FILE *file;
} ARMCPUListState;

/* Sort alphabetically by type name, except for "any". */
static gint arm_cpu_list_compare(gconstpointer a, gconstpointer b)
{
    ObjectClass *class_a = (ObjectClass *)a;
    ObjectClass *class_b = (ObjectClass *)b;
    const char *name_a, *name_b;

    name_a = object_class_get_name(class_a);
    name_b = object_class_get_name(class_b);
    if (strcmp(name_a, "any") == 0) {
        return 1;
    } else if (strcmp(name_b, "any") == 0) {
        return -1;
    } else {
        return strcmp(name_a, name_b);
    }
}

static void arm_cpu_list_entry(gpointer data, gpointer user_data)
{
    ObjectClass *oc = data;
    ARMCPUListState *s = user_data;

    (*s->cpu_fprintf)(s->file, "  %s\n",
                      object_class_get_name(oc));
}

void arm_cpu_list(FILE *f, fprintf_function cpu_fprintf)
{
    ARMCPUListState s = {
        .file = f,
        .cpu_fprintf = cpu_fprintf,
    };
    GSList *list;

    list = object_class_get_list(TYPE_ARM_CPU, false);
    list = g_slist_sort(list, arm_cpu_list_compare);
    (*cpu_fprintf)(f, "Available CPUs:\n");
    g_slist_foreach(list, arm_cpu_list_entry, &s);
    g_slist_free(list);
}

void define_one_arm_cp_reg_with_opaque(ARMCPU *cpu,
                                       const ARMCPRegInfo *r, void *opaque)
{
    /* Define implementations of coprocessor registers.
     * We store these in a hashtable because typically
     * there are less than 150 registers in a space which
     * is 16*16*16*8*8 = 262144 in size.
     * Wildcarding is supported for the crm, opc1 and opc2 fields.
     * If a register is defined twice then the second definition is
     * used, so this can be used to define some generic registers and
     * then override them with implementation specific variations.
     * At least one of the original and the second definition should
     * include ARM_CP_OVERRIDE in its type bits -- this is just a guard
     * against accidental use.
     */
    int crm, opc1, opc2;
    int crmmin = (r->crm == CP_ANY) ? 0 : r->crm;
    int crmmax = (r->crm == CP_ANY) ? 15 : r->crm;
    int opc1min = (r->opc1 == CP_ANY) ? 0 : r->opc1;
    int opc1max = (r->opc1 == CP_ANY) ? 7 : r->opc1;
    int opc2min = (r->opc2 == CP_ANY) ? 0 : r->opc2;
    int opc2max = (r->opc2 == CP_ANY) ? 7 : r->opc2;
    /* 64 bit registers have only CRm and Opc1 fields */
    assert(!((r->type & ARM_CP_64BIT) && (r->opc2 || r->crn)));
    /* Check that the register definition has enough info to handle
     * reads and writes if they are permitted.
     */
    if (!(r->type & (ARM_CP_SPECIAL|ARM_CP_CONST))) {
        if (r->access & PL3_R) {
            assert(r->fieldoffset || r->readfn);
        }
        if (r->access & PL3_W) {
            assert(r->fieldoffset || r->writefn);
        }
    }
    /* Bad type field probably means missing sentinel at end of reg list */
    assert(cptype_valid(r->type));
    for (crm = crmmin; crm <= crmmax; crm++) {
        for (opc1 = opc1min; opc1 <= opc1max; opc1++) {
            for (opc2 = opc2min; opc2 <= opc2max; opc2++) {
                uint32_t *key = g_new(uint32_t, 1);
                ARMCPRegInfo *r2 = g_memdup(r, sizeof(ARMCPRegInfo));
                int is64 = (r->type & ARM_CP_64BIT) ? 1 : 0;
                *key = ENCODE_CP_REG(r->cp, is64, r->crn, crm, opc1, opc2);
                r2->opaque = opaque;
                /* Make sure reginfo passed to helpers for wildcarded regs
                 * has the correct crm/opc1/opc2 for this reg, not CP_ANY:
                 */
                r2->crm = crm;
                r2->opc1 = opc1;
                r2->opc2 = opc2;
                /* Overriding of an existing definition must be explicitly
                 * requested.
                 */
                if (!(r->type & ARM_CP_OVERRIDE)) {
                    ARMCPRegInfo *oldreg;
                    oldreg = g_hash_table_lookup(cpu->cp_regs, key);
                    if (oldreg && !(oldreg->type & ARM_CP_OVERRIDE)) {
                        fprintf(stderr, "Register redefined: cp=%d %d bit "
                                "crn=%d crm=%d opc1=%d opc2=%d, "
                                "was %s, now %s\n", r2->cp, 32 + 32 * is64,
                                r2->crn, r2->crm, r2->opc1, r2->opc2,
                                oldreg->name, r2->name);
                        assert(0);
                    }
                }
                g_hash_table_insert(cpu->cp_regs, key, r2);
            }
        }
    }
}

void define_arm_cp_regs_with_opaque(ARMCPU *cpu,
                                    const ARMCPRegInfo *regs, void *opaque)
{
    /* Define a whole list of registers */
    const ARMCPRegInfo *r;
    for (r = regs; r->type != ARM_CP_SENTINEL; r++) {
        define_one_arm_cp_reg_with_opaque(cpu, r, opaque);
    }
}

const ARMCPRegInfo *get_arm_cp_reginfo(ARMCPU *cpu, uint32_t encoded_cp)
{
    return g_hash_table_lookup(cpu->cp_regs, &encoded_cp);
}

int arm_cp_write_ignore(CPUARMState *env, const ARMCPRegInfo *ri,
                        uint64_t value)
{
    /* Helper coprocessor write function for write-ignore registers */
    return 0;
}

int arm_cp_read_zero(CPUARMState *env, const ARMCPRegInfo *ri, uint64_t *value)
{
    /* Helper coprocessor write function for read-as-zero registers */
    *value = 0;
    return 0;
}

static int bad_mode_switch(CPUARMState *env, int mode)
{
    /* Return true if it is not valid for us to switch to
     * this CPU mode (ie all the UNPREDICTABLE cases in
     * the ARM ARM CPSRWriteByInstr pseudocode).
     */
    switch (mode) {
    case ARM_CPU_MODE_USR:
    case ARM_CPU_MODE_SYS:
    case ARM_CPU_MODE_SVC:
    case ARM_CPU_MODE_ABT:
    case ARM_CPU_MODE_UND:
    case ARM_CPU_MODE_IRQ:
    case ARM_CPU_MODE_FIQ:
        return 0;
    default:
        return 1;
    }
}

uint32_t cpsr_read(CPUARMState *env)
{
    int ZF;
    ZF = (env->ZF == 0);
    return env->uncached_cpsr | (env->NF & 0x80000000) | (ZF << 30) |
        (env->CF << 29) | ((env->VF & 0x80000000) >> 3) | (env->QF << 27)
        | (env->thumb << 5) | ((env->condexec_bits & 3) << 25)
        | ((env->condexec_bits & 0xfc) << 8)
        | (env->GE << 16);
}

void cpsr_write(CPUARMState *env, uint32_t val, uint32_t mask)
{
    if (mask & CPSR_NZCV) {
        env->ZF = (~val) & CPSR_Z;
        env->NF = val;
        env->CF = (val >> 29) & 1;
        env->VF = (val << 3) & 0x80000000;
    }
    if (mask & CPSR_Q)
        env->QF = ((val & CPSR_Q) != 0);
    if (mask & CPSR_T)
        env->thumb = ((val & CPSR_T) != 0);
    if (mask & CPSR_IT_0_1) {
        env->condexec_bits &= ~3;
        env->condexec_bits |= (val >> 25) & 3;
    }
    if (mask & CPSR_IT_2_7) {
        env->condexec_bits &= 3;
        env->condexec_bits |= (val >> 8) & 0xfc;
    }
    if (mask & CPSR_GE) {
        env->GE = (val >> 16) & 0xf;
    }

    if ((env->uncached_cpsr ^ val) & mask & CPSR_M) {
        if (bad_mode_switch(env, val & CPSR_M)) {
            /* Attempt to switch to an invalid mode: this is UNPREDICTABLE.
             * We choose to ignore the attempt and leave the CPSR M field
             * untouched.
             */
            mask &= ~CPSR_M;
        } else {
            switch_mode(env, val & CPSR_M);
        }
    }
    mask &= ~CACHED_CPSR_BITS;
    env->uncached_cpsr = (env->uncached_cpsr & ~mask) | (val & mask);
}

/* Sign/zero extend */
uint32_t HELPER(sxtb16)(uint32_t x)
{
    uint32_t res;
    res = (uint16_t)(int8_t)x;
    res |= (uint32_t)(int8_t)(x >> 16) << 16;
    return res;
}

uint32_t HELPER(uxtb16)(uint32_t x)
{
    uint32_t res;
    res = (uint16_t)(uint8_t)x;
    res |= (uint32_t)(uint8_t)(x >> 16) << 16;
    return res;
}

uint32_t HELPER(clz)(uint32_t x)
{
    return clz32(x);
}

int32_t HELPER(sdiv)(int32_t num, int32_t den)
{
    if (den == 0)
      return 0;
    if (num == INT_MIN && den == -1)
      return INT_MIN;
    return num / den;
}

uint32_t HELPER(udiv)(uint32_t num, uint32_t den)
{
    if (den == 0)
      return 0;
    return num / den;
}

uint32_t HELPER(rbit)(uint32_t x)
{
    x =  ((x & 0xff000000) >> 24)
       | ((x & 0x00ff0000) >> 8)
       | ((x & 0x0000ff00) << 8)
       | ((x & 0x000000ff) << 24);
    x =  ((x & 0xf0f0f0f0) >> 4)
       | ((x & 0x0f0f0f0f) << 4);
    x =  ((x & 0x88888888) >> 3)
       | ((x & 0x44444444) >> 1)
       | ((x & 0x22222222) << 1)
       | ((x & 0x11111111) << 3);
    return x;
}

uint32_t HELPER(abs)(uint32_t x)
{
    return ((int32_t)x < 0) ? -x : x;
}

#if defined(CONFIG_USER_ONLY)

void do_interrupt (CPUARMState *env)
{
    env->exception_index = -1;
}

int cpu_arm_handle_mmu_fault (CPUARMState *env, target_ulong address, int rw,
                              int mmu_idx)
{
    if (rw == 2) {
        env->exception_index = EXCP_PREFETCH_ABORT;
        env->cp15.c6_insn = address;
    } else {
        env->exception_index = EXCP_DATA_ABORT;
        env->cp15.c6_data = address;
    }
    return 1;
}

void HELPER(set_cp15)(CPUARMState *env, uint32_t insn, uint32_t val)
{
    cpu_abort(env, "cp15 insn %08x\n", insn);
}

uint32_t HELPER(get_cp15)(CPUARMState *env, uint32_t insn)
{
    cpu_abort(env, "cp15 insn %08x\n", insn);
}

/* These should probably raise undefined insn exceptions.  */
void HELPER(v7m_msr)(CPUARMState *env, uint32_t reg, uint32_t val)
{
    cpu_abort(env, "v7m_mrs %d\n", reg);
}

uint32_t HELPER(v7m_mrs)(CPUARMState *env, uint32_t reg)
{
    cpu_abort(env, "v7m_mrs %d\n", reg);
    return 0;
}

void switch_mode(CPUARMState *env, int mode)
{
    if (mode != ARM_CPU_MODE_USR)
        cpu_abort(env, "Tried to switch out of user mode\n");
}

void HELPER(set_r13_banked)(CPUARMState *env, uint32_t mode, uint32_t val)
{
    cpu_abort(env, "banked r13 write\n");
}

uint32_t HELPER(get_r13_banked)(CPUARMState *env, uint32_t mode)
{
    cpu_abort(env, "banked r13 read\n");
    return 0;
}

#else

/* Map CPU modes onto saved register banks.  */
static inline int bank_number(CPUARMState *env, int mode)
{
    switch (mode) {
    case ARM_CPU_MODE_USR:
    case ARM_CPU_MODE_SYS:
        return 0;
    case ARM_CPU_MODE_SVC:
        return 1;
    case ARM_CPU_MODE_ABT:
        return 2;
    case ARM_CPU_MODE_UND:
        return 3;
    case ARM_CPU_MODE_IRQ:
        return 4;
    case ARM_CPU_MODE_FIQ:
        return 5;
    }
    cpu_abort(env, "Bad mode %x\n", mode);
    return -1;
}

void switch_mode(CPUARMState *env, int mode)
{
    int old_mode;
    int i;

    old_mode = env->uncached_cpsr & CPSR_M;
    if (mode == old_mode)
        return;

    if (old_mode == ARM_CPU_MODE_FIQ) {
        memcpy (env->fiq_regs, env->regs + 8, 5 * sizeof(uint32_t));
        memcpy (env->regs + 8, env->usr_regs, 5 * sizeof(uint32_t));
    } else if (mode == ARM_CPU_MODE_FIQ) {
        memcpy (env->usr_regs, env->regs + 8, 5 * sizeof(uint32_t));
        memcpy (env->regs + 8, env->fiq_regs, 5 * sizeof(uint32_t));
    }

    i = bank_number(env, old_mode);
    env->banked_r13[i] = env->regs[13];
    env->banked_r14[i] = env->regs[14];
    env->banked_spsr[i] = env->spsr;

    i = bank_number(env, mode);
    env->regs[13] = env->banked_r13[i];
    env->regs[14] = env->banked_r14[i];
    env->spsr = env->banked_spsr[i];
}

static void v7m_push(CPUARMState *env, uint32_t val)
{
    env->regs[13] -= 4;
    stl_phys(env->regs[13], val);
}

static uint32_t v7m_pop(CPUARMState *env)
{
    uint32_t val;
    val = ldl_phys(env->regs[13]);
    env->regs[13] += 4;
    return val;
}

/* Switch to V7M main or process stack pointer.  */
static void switch_v7m_sp(CPUARMState *env, int process)
{
    uint32_t tmp;
    if (env->v7m.current_sp != process) {
        tmp = env->v7m.other_sp;
        env->v7m.other_sp = env->regs[13];
        env->regs[13] = tmp;
        env->v7m.current_sp = process;
    }
}

static void do_v7m_exception_exit(CPUARMState *env)
{
    uint32_t type;
    uint32_t xpsr;

    type = env->regs[15];
    if (env->v7m.exception != 0)
        armv7m_nvic_complete_irq(env->nvic, env->v7m.exception);

    /* Switch to the target stack.  */
    switch_v7m_sp(env, (type & 4) != 0);
    /* Pop registers.  */
    env->regs[0] = v7m_pop(env);
    env->regs[1] = v7m_pop(env);
    env->regs[2] = v7m_pop(env);
    env->regs[3] = v7m_pop(env);
    env->regs[12] = v7m_pop(env);
    env->regs[14] = v7m_pop(env);
    env->regs[15] = v7m_pop(env);
    xpsr = v7m_pop(env);
    xpsr_write(env, xpsr, 0xfffffdff);
    /* Undo stack alignment.  */
    if (xpsr & 0x200)
        env->regs[13] |= 4;
    /* ??? The exception return type specifies Thread/Handler mode.  However
       this is also implied by the xPSR value. Not sure what to do
       if there is a mismatch.  */
    /* ??? Likewise for mismatches between the CONTROL register and the stack
       pointer.  */
}

static void do_interrupt_v7m(CPUARMState *env)
{
    uint32_t xpsr = xpsr_read(env);
    uint32_t lr;
    uint32_t addr;

    lr = 0xfffffff1;
    if (env->v7m.current_sp)
        lr |= 4;
    if (env->v7m.exception == 0)
        lr |= 8;

    /* For exceptions we just mark as pending on the NVIC, and let that
       handle it.  */
    /* TODO: Need to escalate if the current priority is higher than the
       one we're raising.  */
    switch (env->exception_index) {
    case EXCP_UDEF:
        armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_USAGE);
        return;
    case EXCP_SWI:
        env->regs[15] += 2;
        armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_SVC);
        return;
    case EXCP_PREFETCH_ABORT:
    case EXCP_DATA_ABORT:
        armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_MEM);
        return;
    case EXCP_BKPT:
        if (semihosting_enabled) {
            int nr;
            nr = arm_lduw_code(env->regs[15], env->bswap_code) & 0xff;
            if (nr == 0xab) {
                env->regs[15] += 2;
                env->regs[0] = do_arm_semihosting(env);
                return;
            }
        }
        armv7m_nvic_set_pending(env->nvic, ARMV7M_EXCP_DEBUG);
        return;
    case EXCP_IRQ:
        env->v7m.exception = armv7m_nvic_acknowledge_irq(env->nvic);
        break;
    case EXCP_EXCEPTION_EXIT:
        do_v7m_exception_exit(env);
        return;
    default:
        cpu_abort(env, "Unhandled exception 0x%x\n", env->exception_index);
        return; /* Never happens.  Keep compiler happy.  */
    }

    /* Align stack pointer.  */
    /* ??? Should only do this if Configuration Control Register
       STACKALIGN bit is set.  */
    if (env->regs[13] & 4) {
        env->regs[13] -= 4;
        xpsr |= 0x200;
    }
    /* Switch to the handler mode.  */
    v7m_push(env, xpsr);
    v7m_push(env, env->regs[15]);
    v7m_push(env, env->regs[14]);
    v7m_push(env, env->regs[12]);
    v7m_push(env, env->regs[3]);
    v7m_push(env, env->regs[2]);
    v7m_push(env, env->regs[1]);
    v7m_push(env, env->regs[0]);
    switch_v7m_sp(env, 0);
    /* Clear IT bits */
    env->condexec_bits = 0;
    env->regs[14] = lr;
    addr = ldl_phys(env->v7m.vecbase + env->v7m.exception * 4);
    env->regs[15] = addr & 0xfffffffe;
    env->thumb = addr & 1;
}

/* Handle a CPU exception.  */
void do_interrupt(CPUARMState *env)
{
    uint32_t addr;
    uint32_t mask;
    int new_mode;
    uint32_t offset;

    if (IS_M(env)) {
        do_interrupt_v7m(env);
        return;
    }
    /* TODO: Vectored interrupt controller.  */
    switch (env->exception_index) {
    case EXCP_UDEF:
        new_mode = ARM_CPU_MODE_UND;
        addr = 0x04;
        mask = CPSR_I;
        if (env->thumb)
            offset = 2;
        else
            offset = 4;
        break;
    case EXCP_SWI:
        if (semihosting_enabled) {
            /* Check for semihosting interrupt.  */
            if (env->thumb) {
                mask = arm_lduw_code(env->regs[15] - 2, env->bswap_code) & 0xff;
            } else {
                mask = arm_ldl_code(env->regs[15] - 4, env->bswap_code)
                    & 0xffffff;
            }
            /* Only intercept calls from privileged modes, to provide some
               semblance of security.  */
            if (((mask == 0x123456 && !env->thumb)
                    || (mask == 0xab && env->thumb))
                  && (env->uncached_cpsr & CPSR_M) != ARM_CPU_MODE_USR) {
                env->regs[0] = do_arm_semihosting(env);
                return;
            }
        }
        new_mode = ARM_CPU_MODE_SVC;
        addr = 0x08;
        mask = CPSR_I;
        /* The PC already points to the next instruction.  */
        offset = 0;
        break;
    case EXCP_BKPT:
        /* See if this is a semihosting syscall.  */
        if (env->thumb && semihosting_enabled) {
            mask = arm_lduw_code(env->regs[15], env->bswap_code) & 0xff;
            if (mask == 0xab
                  && (env->uncached_cpsr & CPSR_M) != ARM_CPU_MODE_USR) {
                env->regs[15] += 2;
                env->regs[0] = do_arm_semihosting(env);
                return;
            }
        }
        env->cp15.c5_insn = 2;
        /* Fall through to prefetch abort.  */
    case EXCP_PREFETCH_ABORT:
        new_mode = ARM_CPU_MODE_ABT;
        addr = 0x0c;
        mask = CPSR_A | CPSR_I;
        offset = 4;
        break;
    case EXCP_DATA_ABORT:
        new_mode = ARM_CPU_MODE_ABT;
        addr = 0x10;
        mask = CPSR_A | CPSR_I;
        offset = 8;
        break;
    case EXCP_IRQ:
        new_mode = ARM_CPU_MODE_IRQ;
        addr = 0x18;
        /* Disable IRQ and imprecise data aborts.  */
        mask = CPSR_A | CPSR_I;
        offset = 4;
        break;
    case EXCP_FIQ:
        new_mode = ARM_CPU_MODE_FIQ;
        addr = 0x1c;
        /* Disable FIQ, IRQ and imprecise data aborts.  */
        mask = CPSR_A | CPSR_I | CPSR_F;
        offset = 4;
        break;
    default:
        cpu_abort(env, "Unhandled exception 0x%x\n", env->exception_index);
        return; /* Never happens.  Keep compiler happy.  */
    }
    /* High vectors.  */
    if (env->cp15.c1_sys & (1 << 13)) {
        addr += 0xffff0000;
    }
    switch_mode (env, new_mode);
    env->spsr = cpsr_read(env);
    /* Clear IT bits.  */
    env->condexec_bits = 0;
    /* Switch to the new mode, and to the correct instruction set.  */
    env->uncached_cpsr = (env->uncached_cpsr & ~CPSR_M) | new_mode;
    env->uncached_cpsr |= mask;
    /* this is a lie, as the was no c1_sys on V4T/V5, but who cares
     * and we should just guard the thumb mode on V4 */
    if (arm_feature(env, ARM_FEATURE_V4T)) {
        env->thumb = (env->cp15.c1_sys & (1 << 30)) != 0;
    }
    env->regs[14] = env->regs[15] + offset;
    env->regs[15] = addr;
    env->interrupt_request |= CPU_INTERRUPT_EXITTB;
}

/* Check section/page access permissions.
   Returns the page protection flags, or zero if the access is not
   permitted.  */
static inline int check_ap(CPUARMState *env, int ap, int domain_prot,
                           int access_type, int is_user)
{
  int prot_ro;

  if (domain_prot == 3) {
    return PAGE_READ | PAGE_WRITE;
  }

  if (access_type == 1)
      prot_ro = 0;
  else
      prot_ro = PAGE_READ;

  switch (ap) {
  case 0:
      if (access_type == 1)
          return 0;
      switch ((env->cp15.c1_sys >> 8) & 3) {
      case 1:
          return is_user ? 0 : PAGE_READ;
      case 2:
          return PAGE_READ;
      default:
          return 0;
      }
  case 1:
      return is_user ? 0 : PAGE_READ | PAGE_WRITE;
  case 2:
      if (is_user)
          return prot_ro;
      else
          return PAGE_READ | PAGE_WRITE;
  case 3:
      return PAGE_READ | PAGE_WRITE;
  case 4: /* Reserved.  */
      return 0;
  case 5:
      return is_user ? 0 : prot_ro;
  case 6:
      return prot_ro;
  case 7:
      if (!arm_feature (env, ARM_FEATURE_V6K))
          return 0;
      return prot_ro;
  default:
      abort();
  }
}

static uint32_t get_level1_table_address(CPUARMState *env, uint32_t address)
{
    uint32_t table;

    if (address & env->cp15.c2_mask)
        table = env->cp15.c2_base1 & 0xffffc000;
    else
        table = env->cp15.c2_base0 & env->cp15.c2_base_mask;

    table |= (address >> 18) & 0x3ffc;
    return table;
}

static int get_phys_addr_v5(CPUARMState *env, uint32_t address, int access_type,
                            int is_user, uint32_t *phys_ptr, int *prot,
                            target_ulong *page_size)
{
    int code;
    uint32_t table;
    uint32_t desc;
    int type;
    int ap;
    int domain;
    int domain_prot;
    uint32_t phys_addr;

    /* Pagetable walk.  */
    /* Lookup l1 descriptor.  */
    table = get_level1_table_address(env, address);
    desc = ldl_phys(table);
    type = (desc & 3);
    domain = (desc >> 5) & 0x0f;
    domain_prot = (env->cp15.c3 >> (domain * 2)) & 3;
    if (type == 0) {
        /* Section translation fault.  */
        code = 5;
        goto do_fault;
    }
    if (domain_prot == 0 || domain_prot == 2) {
        if (type == 2)
            code = 9; /* Section domain fault.  */
        else
            code = 11; /* Page domain fault.  */
        goto do_fault;
    }
    if (type == 2) {
        /* 1Mb section.  */
        phys_addr = (desc & 0xfff00000) | (address & 0x000fffff);
        ap = (desc >> 10) & 3;
        code = 13;
        *page_size = 1024 * 1024;
    } else {
        /* Lookup l2 entry.  */
        if (type == 1) {
            /* Coarse pagetable.  */
            table = (desc & 0xfffffc00) | ((address >> 10) & 0x3fc);
        } else {
            /* Fine pagetable.  */
            table = (desc & 0xfffff000) | ((address >> 8) & 0xffc);
        }
        desc = ldl_phys(table);
        switch (desc & 3) {
        case 0: /* Page translation fault.  */
            code = 7;
            goto do_fault;
        case 1: /* 64k page.  */
            phys_addr = (desc & 0xffff0000) | (address & 0xffff);
            ap = (desc >> (4 + ((address >> 13) & 6))) & 3;
            *page_size = 0x10000;
            break;
        case 2: /* 4k page.  */
            phys_addr = (desc & 0xfffff000) | (address & 0xfff);
            ap = (desc >> (4 + ((address >> 13) & 6))) & 3;
            *page_size = 0x1000;
            break;
        case 3: /* 1k page.  */
            if (type == 1) {
                if (arm_feature(env, ARM_FEATURE_XSCALE)) {
                    phys_addr = (desc & 0xfffff000) | (address & 0xfff);
                } else {
                    /* Page translation fault.  */
                    code = 7;
                    goto do_fault;
                }
            } else {
                phys_addr = (desc & 0xfffffc00) | (address & 0x3ff);
            }
            ap = (desc >> 4) & 3;
            *page_size = 0x400;
            break;
        default:
            /* Never happens, but compiler isn't smart enough to tell.  */
            abort();
        }
        code = 15;
    }
    *prot = check_ap(env, ap, domain_prot, access_type, is_user);
    if (!*prot) {
        /* Access permission fault.  */
        goto do_fault;
    }
    *prot |= PAGE_EXEC;
    *phys_ptr = phys_addr;
    return 0;
do_fault:
    return code | (domain << 4);
}

static int get_phys_addr_v6(CPUARMState *env, uint32_t address, int access_type,
                            int is_user, uint32_t *phys_ptr, int *prot,
                            target_ulong *page_size)
{
    int code;
    uint32_t table;
    uint32_t desc;
    uint32_t xn;
    int type;
    int ap;
    int domain;
    int domain_prot;
    uint32_t phys_addr;

    /* Pagetable walk.  */
    /* Lookup l1 descriptor.  */
    table = get_level1_table_address(env, address);
    desc = ldl_phys(table);
    type = (desc & 3);
    if (type == 0) {
        /* Section translation fault.  */
        code = 5;
        domain = 0;
        goto do_fault;
    } else if (type == 2 && (desc & (1 << 18))) {
        /* Supersection.  */
        domain = 0;
    } else {
        /* Section or page.  */
        domain = (desc >> 5) & 0x0f;
    }
    domain_prot = (env->cp15.c3 >> (domain * 2)) & 3;
    if (domain_prot == 0 || domain_prot == 2) {
        if (type == 2)
            code = 9; /* Section domain fault.  */
        else
            code = 11; /* Page domain fault.  */
        goto do_fault;
    }
    if (type == 2) {
        if (desc & (1 << 18)) {
            /* Supersection.  */
            phys_addr = (desc & 0xff000000) | (address & 0x00ffffff);
            *page_size = 0x1000000;
        } else {
            /* Section.  */
            phys_addr = (desc & 0xfff00000) | (address & 0x000fffff);
            *page_size = 0x100000;
        }
        ap = ((desc >> 10) & 3) | ((desc >> 13) & 4);
        xn = desc & (1 << 4);
        code = 13;
    } else {
        /* Lookup l2 entry.  */
        table = (desc & 0xfffffc00) | ((address >> 10) & 0x3fc);
        desc = ldl_phys(table);
        ap = ((desc >> 4) & 3) | ((desc >> 7) & 4);
        switch (desc & 3) {
        case 0: /* Page translation fault.  */
            code = 7;
            goto do_fault;
        case 1: /* 64k page.  */
            phys_addr = (desc & 0xffff0000) | (address & 0xffff);
            xn = desc & (1 << 15);
            *page_size = 0x10000;
            break;
        case 2: case 3: /* 4k page.  */
            phys_addr = (desc & 0xfffff000) | (address & 0xfff);
            xn = desc & 1;
            *page_size = 0x1000;
            break;
        default:
            /* Never happens, but compiler isn't smart enough to tell.  */
            abort();
        }
        code = 15;
    }
    if (domain_prot == 3) {
        *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
    } else {
        if (xn && access_type == 2)
            goto do_fault;

        /* The simplified model uses AP[0] as an access control bit.  */
        if ((env->cp15.c1_sys & (1 << 29)) && (ap & 1) == 0) {
            /* Access flag fault.  */
            code = (code == 15) ? 6 : 3;
            goto do_fault;
        }
        *prot = check_ap(env, ap, domain_prot, access_type, is_user);
        if (!*prot) {
            /* Access permission fault.  */
            goto do_fault;
        }
        if (!xn) {
            *prot |= PAGE_EXEC;
        }
    }
    *phys_ptr = phys_addr;
    return 0;
do_fault:
    return code | (domain << 4);
}

static int get_phys_addr_mpu(CPUARMState *env, uint32_t address, int access_type,
                             int is_user, uint32_t *phys_ptr, int *prot)
{
    int n;
    uint32_t mask;
    uint32_t base;

    *phys_ptr = address;
    for (n = 7; n >= 0; n--) {
        base = env->cp15.c6_region[n];
        if ((base & 1) == 0)
            continue;
        mask = 1 << ((base >> 1) & 0x1f);
        /* Keep this shift separate from the above to avoid an
           (undefined) << 32.  */
        mask = (mask << 1) - 1;
        if (((base ^ address) & ~mask) == 0)
            break;
    }
    if (n < 0)
        return 2;

    if (access_type == 2) {
        mask = env->cp15.c5_insn;
    } else {
        mask = env->cp15.c5_data;
    }
    mask = (mask >> (n * 4)) & 0xf;
    switch (mask) {
    case 0:
        return 1;
    case 1:
        if (is_user)
          return 1;
        *prot = PAGE_READ | PAGE_WRITE;
        break;
    case 2:
        *prot = PAGE_READ;
        if (!is_user)
            *prot |= PAGE_WRITE;
        break;
    case 3:
        *prot = PAGE_READ | PAGE_WRITE;
        break;
    case 5:
        if (is_user)
            return 1;
        *prot = PAGE_READ;
        break;
    case 6:
        *prot = PAGE_READ;
        break;
    default:
        /* Bad permission.  */
        return 1;
    }
    *prot |= PAGE_EXEC;
    return 0;
}

static inline int get_phys_addr(CPUARMState *env, uint32_t address,
                                int access_type, int is_user,
                                uint32_t *phys_ptr, int *prot,
                                target_ulong *page_size)
{
    /* Fast Context Switch Extension.  */
    if (address < 0x02000000)
        address += env->cp15.c13_fcse;

    if ((env->cp15.c1_sys & 1) == 0) {
        /* MMU/MPU disabled.  */
        *phys_ptr = address;
        *prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
        *page_size = TARGET_PAGE_SIZE;
        return 0;
    } else if (arm_feature(env, ARM_FEATURE_MPU)) {
        *page_size = TARGET_PAGE_SIZE;
        return get_phys_addr_mpu(env, address, access_type, is_user, phys_ptr,
                                 prot);
    } else if (env->cp15.c1_sys & (1 << 23)) {
        return get_phys_addr_v6(env, address, access_type, is_user, phys_ptr,
                                prot, page_size);
    } else {
        return get_phys_addr_v5(env, address, access_type, is_user, phys_ptr,
                                prot, page_size);
    }
}

int cpu_arm_handle_mmu_fault (CPUARMState *env, target_ulong address,
                              int access_type, int mmu_idx)
{
    uint32_t phys_addr;
    target_ulong page_size;
    int prot;
    int ret, is_user;

    is_user = mmu_idx == MMU_USER_IDX;
    ret = get_phys_addr(env, address, access_type, is_user, &phys_addr, &prot,
                        &page_size);
    if (ret == 0) {
        /* Map a single [sub]page.  */
        phys_addr &= ~(uint32_t)0x3ff;
        address &= ~(uint32_t)0x3ff;
        tlb_set_page (env, address, phys_addr, prot, mmu_idx, page_size);
        return 0;
    }

    if (access_type == 2) {
        env->cp15.c5_insn = ret;
        env->cp15.c6_insn = address;
        env->exception_index = EXCP_PREFETCH_ABORT;
    } else {
        env->cp15.c5_data = ret;
        if (access_type == 1 && arm_feature(env, ARM_FEATURE_V6))
            env->cp15.c5_data |= (1 << 11);
        env->cp15.c6_data = address;
        env->exception_index = EXCP_DATA_ABORT;
    }
    return 1;
}

target_phys_addr_t cpu_get_phys_page_debug(CPUARMState *env, target_ulong addr)
{
    uint32_t phys_addr;
    target_ulong page_size;
    int prot;
    int ret;

    ret = get_phys_addr(env, addr, 0, 0, &phys_addr, &prot, &page_size);

    if (ret != 0)
        return -1;

    return phys_addr;
}

/* Return basic MPU access permission bits.  */
static uint32_t simple_mpu_ap_bits(uint32_t val)
{
    uint32_t ret;
    uint32_t mask;
    int i;
    ret = 0;
    mask = 3;
    for (i = 0; i < 16; i += 2) {
        ret |= (val >> i) & mask;
        mask <<= 2;
    }
    return ret;
}

/* Pad basic MPU access permission bits to extended format.  */
static uint32_t extended_mpu_ap_bits(uint32_t val)
{
    uint32_t ret;
    uint32_t mask;
    int i;
    ret = 0;
    mask = 3;
    for (i = 0; i < 16; i += 2) {
        ret |= (val & mask) << i;
        mask <<= 2;
    }
    return ret;
}

void HELPER(set_cp15)(CPUARMState *env, uint32_t insn, uint32_t val)
{
    int op1;
    int op2;
    int crm;

    op1 = (insn >> 21) & 7;
    op2 = (insn >> 5) & 7;
    crm = insn & 0xf;
    switch ((insn >> 16) & 0xf) {
    case 0:
        /* ID codes.  */
        if (arm_feature(env, ARM_FEATURE_XSCALE))
            break;
        if (arm_feature(env, ARM_FEATURE_OMAPCP))
            break;
        if (arm_feature(env, ARM_FEATURE_V7)
                && op1 == 2 && crm == 0 && op2 == 0) {
            env->cp15.c0_cssel = val & 0xf;
            break;
        }
        goto bad_reg;
    case 1: /* System configuration.  */
        if (arm_feature(env, ARM_FEATURE_V7)
                && op1 == 0 && crm == 1 && op2 == 0) {
            env->cp15.c1_scr = val;
            break;
        }
        if (arm_feature(env, ARM_FEATURE_OMAPCP))
            op2 = 0;
        switch (op2) {
        case 0:
            if (!arm_feature(env, ARM_FEATURE_XSCALE) || crm == 0)
                env->cp15.c1_sys = val;
            /* ??? Lots of these bits are not implemented.  */
            /* This may enable/disable the MMU, so do a TLB flush.  */
            tlb_flush(env, 1);
            break;
        case 1: /* Auxiliary control register.  */
            if (arm_feature(env, ARM_FEATURE_XSCALE)) {
                env->cp15.c1_xscaleauxcr = val;
                break;
            }
            /* Not implemented.  */
            break;
        case 2:
            if (arm_feature(env, ARM_FEATURE_XSCALE))
                goto bad_reg;
            if (env->cp15.c1_coproc != val) {
                env->cp15.c1_coproc = val;
                /* ??? Is this safe when called from within a TB?  */
                tb_flush(env);
            }
            break;
        default:
            goto bad_reg;
        }
        break;
    case 2: /* MMU Page table control / MPU cache control.  */
        if (arm_feature(env, ARM_FEATURE_MPU)) {
            switch (op2) {
            case 0:
                env->cp15.c2_data = val;
                break;
            case 1:
                env->cp15.c2_insn = val;
                break;
            default:
                goto bad_reg;
            }
        } else {
            switch (op2) {
            case 0:
                env->cp15.c2_base0 = val;
                break;
            case 1:
                env->cp15.c2_base1 = val;
                break;
            case 2:
                val &= 7;
                env->cp15.c2_control = val;
                env->cp15.c2_mask = ~(((uint32_t)0xffffffffu) >> val);
                env->cp15.c2_base_mask = ~((uint32_t)0x3fffu >> val);
                break;
            default:
                goto bad_reg;
            }
        }
        break;
    case 3: /* MMU Domain access control / MPU write buffer control.  */
        env->cp15.c3 = val;
        tlb_flush(env, 1); /* Flush TLB as domain not tracked in TLB */
        break;
    case 4: /* Reserved.  */
        goto bad_reg;
    case 5: /* MMU Fault status / MPU access permission.  */
        if (arm_feature(env, ARM_FEATURE_OMAPCP))
            op2 = 0;
        switch (op2) {
        case 0:
            if (arm_feature(env, ARM_FEATURE_MPU))
                val = extended_mpu_ap_bits(val);
            env->cp15.c5_data = val;
            break;
        case 1:
            if (arm_feature(env, ARM_FEATURE_MPU))
                val = extended_mpu_ap_bits(val);
            env->cp15.c5_insn = val;
            break;
        case 2:
            if (!arm_feature(env, ARM_FEATURE_MPU))
                goto bad_reg;
            env->cp15.c5_data = val;
            break;
        case 3:
            if (!arm_feature(env, ARM_FEATURE_MPU))
                goto bad_reg;
            env->cp15.c5_insn = val;
            break;
        default:
            goto bad_reg;
        }
        break;
    case 6: /* MMU Fault address / MPU base/size.  */
        if (arm_feature(env, ARM_FEATURE_MPU)) {
            if (crm >= 8)
                goto bad_reg;
            env->cp15.c6_region[crm] = val;
        } else {
            if (arm_feature(env, ARM_FEATURE_OMAPCP))
                op2 = 0;
            switch (op2) {
            case 0:
                env->cp15.c6_data = val;
                break;
            case 1: /* ??? This is WFAR on armv6 */
            case 2:
                env->cp15.c6_insn = val;
                break;
            default:
                goto bad_reg;
            }
        }
        break;
    case 7: /* Cache control.  */
        env->cp15.c15_i_max = 0x000;
        env->cp15.c15_i_min = 0xff0;
        if (op1 != 0) {
            goto bad_reg;
        }
        /* No cache, so nothing to do except VA->PA translations. */
        if (arm_feature(env, ARM_FEATURE_VAPA)) {
            switch (crm) {
            case 4:
                if (arm_feature(env, ARM_FEATURE_V7)) {
                    env->cp15.c7_par = val & 0xfffff6ff;
                } else {
                    env->cp15.c7_par = val & 0xfffff1ff;
                }
                break;
            case 8: {
                uint32_t phys_addr;
                target_ulong page_size;
                int prot;
                int ret, is_user = op2 & 2;
                int access_type = op2 & 1;

                if (op2 & 4) {
                    /* Other states are only available with TrustZone */
                    goto bad_reg;
                }
                ret = get_phys_addr(env, val, access_type, is_user,
                                    &phys_addr, &prot, &page_size);
                if (ret == 0) {
                    /* We do not set any attribute bits in the PAR */
                    if (page_size == (1 << 24)
                        && arm_feature(env, ARM_FEATURE_V7)) {
                        env->cp15.c7_par = (phys_addr & 0xff000000) | 1 << 1;
                    } else {
                        env->cp15.c7_par = phys_addr & 0xfffff000;
                    }
                } else {
                    env->cp15.c7_par = ((ret & (10 << 1)) >> 5) |
                                       ((ret & (12 << 1)) >> 6) |
                                       ((ret & 0xf) << 1) | 1;
                }
                break;
            }
            }
        }
        break;
    case 8: /* MMU TLB control.  */
        switch (op2) {
        case 0: /* Invalidate all (TLBIALL) */
            tlb_flush(env, 1);
            break;
        case 1: /* Invalidate single TLB entry by MVA and ASID (TLBIMVA) */
            tlb_flush_page(env, val & TARGET_PAGE_MASK);
            break;
        case 2: /* Invalidate by ASID (TLBIASID) */
            tlb_flush(env, val == 0);
            break;
        case 3: /* Invalidate single entry by MVA, all ASIDs (TLBIMVAA) */
            tlb_flush_page(env, val & TARGET_PAGE_MASK);
            break;
        default:
            goto bad_reg;
        }
        break;
    case 9:
        if (arm_feature(env, ARM_FEATURE_OMAPCP))
            break;
        if (arm_feature(env, ARM_FEATURE_STRONGARM))
            break; /* Ignore ReadBuffer access */
        switch (crm) {
        case 0: /* Cache lockdown.  */
            switch (op1) {
            case 0: /* L1 cache.  */
                switch (op2) {
                case 0:
                    env->cp15.c9_data = val;
                    break;
                case 1:
                    env->cp15.c9_insn = val;
                    break;
                default:
                    goto bad_reg;
                }
                break;
            case 1: /* L2 cache.  */
                /* Ignore writes to L2 lockdown/auxiliary registers.  */
                break;
            default:
                goto bad_reg;
            }
            break;
        case 1: /* TCM memory region registers.  */
            /* Not implemented.  */
            goto bad_reg;
        case 12: /* Performance monitor control */
            /* Performance monitors are implementation defined in v7,
             * but with an ARM recommended set of registers, which we
             * follow (although we don't actually implement any counters)
             */
            if (!arm_feature(env, ARM_FEATURE_V7)) {
                goto bad_reg;
            }
            switch (op2) {
            case 0: /* performance monitor control register */
                /* only the DP, X, D and E bits are writable */
                env->cp15.c9_pmcr &= ~0x39;
                env->cp15.c9_pmcr |= (val & 0x39);
                break;
            case 1: /* Count enable set register */
                val &= (1 << 31);
                env->cp15.c9_pmcnten |= val;
                break;
            case 2: /* Count enable clear */
                val &= (1 << 31);
                env->cp15.c9_pmcnten &= ~val;
                break;
            case 3: /* Overflow flag status */
                env->cp15.c9_pmovsr &= ~val;
                break;
            case 4: /* Software increment */
                /* RAZ/WI since we don't implement the software-count event */
                break;
            case 5: /* Event counter selection register */
                /* Since we don't implement any events, writing to this register
                 * is actually UNPREDICTABLE. So we choose to RAZ/WI.
                 */
                break;
            default:
                goto bad_reg;
            }
            break;
        case 13: /* Performance counters */
            if (!arm_feature(env, ARM_FEATURE_V7)) {
                goto bad_reg;
            }
            switch (op2) {
            case 0: /* Cycle count register: not implemented, so RAZ/WI */
                break;
            case 1: /* Event type select */
                env->cp15.c9_pmxevtyper = val & 0xff;
                break;
            case 2: /* Event count register */
                /* Unimplemented (we have no events), RAZ/WI */
                break;
            default:
                goto bad_reg;
            }
            break;
        case 14: /* Performance monitor control */
            if (!arm_feature(env, ARM_FEATURE_V7)) {
                goto bad_reg;
            }
            switch (op2) {
            case 0: /* user enable */
                env->cp15.c9_pmuserenr = val & 1;
                /* changes access rights for cp registers, so flush tbs */
                tb_flush(env);
                break;
            case 1: /* interrupt enable set */
                /* We have no event counters so only the C bit can be changed */
                val &= (1 << 31);
                env->cp15.c9_pminten |= val;
                break;
            case 2: /* interrupt enable clear */
                val &= (1 << 31);
                env->cp15.c9_pminten &= ~val;
                break;
            }
            break;
        default:
            goto bad_reg;
        }
        break;
    case 10: /* MMU TLB lockdown.  */
        /* ??? TLB lockdown not implemented.  */
        break;
    case 12: /* Reserved.  */
        goto bad_reg;
    case 13: /* Process ID.  */
        switch (op2) {
        case 0:
            /* Unlike real hardware the qemu TLB uses virtual addresses,
               not modified virtual addresses, so this causes a TLB flush.
             */
            if (env->cp15.c13_fcse != val)
              tlb_flush(env, 1);
            env->cp15.c13_fcse = val;
            break;
        case 1:
            /* This changes the ASID, so do a TLB flush.  */
            if (env->cp15.c13_context != val
                && !arm_feature(env, ARM_FEATURE_MPU))
              tlb_flush(env, 0);
            env->cp15.c13_context = val;
            break;
        default:
            goto bad_reg;
        }
        break;
    case 14: /* Generic timer */
        if (arm_feature(env, ARM_FEATURE_GENERIC_TIMER)) {
            /* Dummy implementation: RAZ/WI for all */
            break;
        }
        goto bad_reg;
    case 15: /* Implementation specific.  */
        if (arm_feature(env, ARM_FEATURE_XSCALE)) {
            if (op2 == 0 && crm == 1) {
                if (env->cp15.c15_cpar != (val & 0x3fff)) {
                    /* Changes cp0 to cp13 behavior, so needs a TB flush.  */
                    tb_flush(env);
                    env->cp15.c15_cpar = val & 0x3fff;
                }
                break;
            }
            goto bad_reg;
        }
        if (arm_feature(env, ARM_FEATURE_OMAPCP)) {
            switch (crm) {
            case 0:
                break;
            case 1: /* Set TI925T configuration.  */
                env->cp15.c15_ticonfig = val & 0xe7;
                env->cp15.c0_cpuid = (val & (1 << 5)) ? /* OS_TYPE bit */
                        ARM_CPUID_TI915T : ARM_CPUID_TI925T;
                break;
            case 2: /* Set I_max.  */
                env->cp15.c15_i_max = val;
                break;
            case 3: /* Set I_min.  */
                env->cp15.c15_i_min = val;
                break;
            case 4: /* Set thread-ID.  */
                env->cp15.c15_threadid = val & 0xffff;
                break;
            case 8: /* Wait-for-interrupt (deprecated).  */
                cpu_interrupt(env, CPU_INTERRUPT_HALT);
                break;
            default:
                goto bad_reg;
            }
        }
        if (ARM_CPUID(env) == ARM_CPUID_CORTEXA9) {
            switch (crm) {
            case 0:
                if ((op1 == 0) && (op2 == 0)) {
                    env->cp15.c15_power_control = val;
                } else if ((op1 == 0) && (op2 == 1)) {
                    env->cp15.c15_diagnostic = val;
                } else if ((op1 == 0) && (op2 == 2)) {
                    env->cp15.c15_power_diagnostic = val;
                }
            default:
                break;
            }
        }
        break;
    }
    return;
bad_reg:
    /* ??? For debugging only.  Should raise illegal instruction exception.  */
    cpu_abort(env, "Unimplemented cp15 register write (c%d, c%d, {%d, %d})\n",
              (insn >> 16) & 0xf, crm, op1, op2);
}

uint32_t HELPER(get_cp15)(CPUARMState *env, uint32_t insn)
{
    int op1;
    int op2;
    int crm;

    op1 = (insn >> 21) & 7;
    op2 = (insn >> 5) & 7;
    crm = insn & 0xf;
    switch ((insn >> 16) & 0xf) {
    case 0: /* ID codes.  */
        switch (op1) {
        case 0:
            switch (crm) {
            case 0:
                switch (op2) {
                case 0: /* Device ID.  */
                    return env->cp15.c0_cpuid;
                case 1: /* Cache Type.  */
                    return env->cp15.c0_cachetype;
                case 2: /* TCM status.  */
                    return 0;
                case 3: /* TLB type register.  */
                    return 0; /* No lockable TLB entries.  */
                case 5: /* MPIDR */
                    /* The MPIDR was standardised in v7; prior to
                     * this it was implemented only in the 11MPCore.
                     * For all other pre-v7 cores it does not exist.
                     */
                    if (arm_feature(env, ARM_FEATURE_V7) ||
                        ARM_CPUID(env) == ARM_CPUID_ARM11MPCORE) {
                        int mpidr = env->cpu_index;
                        /* We don't support setting cluster ID ([8..11])
                         * so these bits always RAZ.
                         */
                        if (arm_feature(env, ARM_FEATURE_V7MP)) {
                            mpidr |= (1 << 31);
                            /* Cores which are uniprocessor (non-coherent)
                             * but still implement the MP extensions set
                             * bit 30. (For instance, A9UP.) However we do
                             * not currently model any of those cores.
                             */
                        }
                        return mpidr;
                    }
                    /* otherwise fall through to the unimplemented-reg case */
                default:
                    goto bad_reg;
                }
            case 1:
                if (!arm_feature(env, ARM_FEATURE_V6))
                    goto bad_reg;
                return env->cp15.c0_c1[op2];
            case 2:
                if (!arm_feature(env, ARM_FEATURE_V6))
                    goto bad_reg;
                return env->cp15.c0_c2[op2];
            case 3: case 4: case 5: case 6: case 7:
                return 0;
            default:
                goto bad_reg;
            }
        case 1:
            /* These registers aren't documented on arm11 cores.  However
               Linux looks at them anyway.  */
            if (!arm_feature(env, ARM_FEATURE_V6))
                goto bad_reg;
            if (crm != 0)
                goto bad_reg;
            if (!arm_feature(env, ARM_FEATURE_V7))
                return 0;

            switch (op2) {
            case 0:
                return env->cp15.c0_ccsid[env->cp15.c0_cssel];
            case 1:
                return env->cp15.c0_clid;
            case 7:
                return 0;
            }
            goto bad_reg;
        case 2:
            if (op2 != 0 || crm != 0)
                goto bad_reg;
            return env->cp15.c0_cssel;
        default:
            goto bad_reg;
        }
    case 1: /* System configuration.  */
        if (arm_feature(env, ARM_FEATURE_V7)
            && op1 == 0 && crm == 1 && op2 == 0) {
            return env->cp15.c1_scr;
        }
        if (arm_feature(env, ARM_FEATURE_OMAPCP))
            op2 = 0;
        switch (op2) {
        case 0: /* Control register.  */
            return env->cp15.c1_sys;
        case 1: /* Auxiliary control register.  */
            if (arm_feature(env, ARM_FEATURE_XSCALE))
                return env->cp15.c1_xscaleauxcr;
            if (!arm_feature(env, ARM_FEATURE_AUXCR))
                goto bad_reg;
            switch (ARM_CPUID(env)) {
            case ARM_CPUID_ARM1026:
                return 1;
            case ARM_CPUID_ARM1136:
            case ARM_CPUID_ARM1136_R2:
            case ARM_CPUID_ARM1176:
                return 7;
            case ARM_CPUID_ARM11MPCORE:
                return 1;
            case ARM_CPUID_CORTEXA8:
                return 2;
            case ARM_CPUID_CORTEXA9:
            case ARM_CPUID_CORTEXA15:
                return 0;
            default:
                goto bad_reg;
            }
        case 2: /* Coprocessor access register.  */
            if (arm_feature(env, ARM_FEATURE_XSCALE))
                goto bad_reg;
            return env->cp15.c1_coproc;
        default:
            goto bad_reg;
        }
    case 2: /* MMU Page table control / MPU cache control.  */
        if (arm_feature(env, ARM_FEATURE_MPU)) {
            switch (op2) {
            case 0:
                return env->cp15.c2_data;
                break;
            case 1:
                return env->cp15.c2_insn;
                break;
            default:
                goto bad_reg;
            }
        } else {
            switch (op2) {
            case 0:
                return env->cp15.c2_base0;
            case 1:
                return env->cp15.c2_base1;
            case 2:
                return env->cp15.c2_control;
            default:
                goto bad_reg;
            }
        }
    case 3: /* MMU Domain access control / MPU write buffer control.  */
        return env->cp15.c3;
    case 4: /* Reserved.  */
        goto bad_reg;
    case 5: /* MMU Fault status / MPU access permission.  */
        if (arm_feature(env, ARM_FEATURE_OMAPCP))
            op2 = 0;
        switch (op2) {
        case 0:
            if (arm_feature(env, ARM_FEATURE_MPU))
                return simple_mpu_ap_bits(env->cp15.c5_data);
            return env->cp15.c5_data;
        case 1:
            if (arm_feature(env, ARM_FEATURE_MPU))
                return simple_mpu_ap_bits(env->cp15.c5_insn);
            return env->cp15.c5_insn;
        case 2:
            if (!arm_feature(env, ARM_FEATURE_MPU))
                goto bad_reg;
            return env->cp15.c5_data;
        case 3:
            if (!arm_feature(env, ARM_FEATURE_MPU))
                goto bad_reg;
            return env->cp15.c5_insn;
        default:
            goto bad_reg;
        }
    case 6: /* MMU Fault address.  */
        if (arm_feature(env, ARM_FEATURE_MPU)) {
            if (crm >= 8)
                goto bad_reg;
            return env->cp15.c6_region[crm];
        } else {
            if (arm_feature(env, ARM_FEATURE_OMAPCP))
                op2 = 0;
            switch (op2) {
            case 0:
                return env->cp15.c6_data;
            case 1:
                if (arm_feature(env, ARM_FEATURE_V6)) {
                    /* Watchpoint Fault Adrress.  */
                    return 0; /* Not implemented.  */
                } else {
                    /* Instruction Fault Adrress.  */
                    /* Arm9 doesn't have an IFAR, but implementing it anyway
                       shouldn't do any harm.  */
                    return env->cp15.c6_insn;
                }
            case 2:
                if (arm_feature(env, ARM_FEATURE_V6)) {
                    /* Instruction Fault Adrress.  */
                    return env->cp15.c6_insn;
                } else {
                    goto bad_reg;
                }
            default:
                goto bad_reg;
            }
        }
    case 7: /* Cache control.  */
        if (crm == 4 && op1 == 0 && op2 == 0) {
            return env->cp15.c7_par;
        }
        /* FIXME: Should only clear Z flag if destination is r15.  */
        env->ZF = 0;
        return 0;
    case 8: /* MMU TLB control.  */
        goto bad_reg;
    case 9:
        switch (crm) {
        case 0: /* Cache lockdown */
            switch (op1) {
            case 0: /* L1 cache.  */
                if (arm_feature(env, ARM_FEATURE_OMAPCP)) {
                    return 0;
                }
                switch (op2) {
                case 0:
                    return env->cp15.c9_data;
                case 1:
                    return env->cp15.c9_insn;
                default:
                    goto bad_reg;
                }
            case 1: /* L2 cache */
                /* L2 Lockdown and Auxiliary control.  */
                switch (op2) {
                case 0:
                    /* L2 cache lockdown (A8 only) */
                    return 0;
                case 2:
                    /* L2 cache auxiliary control (A8) or control (A15) */
                    if (ARM_CPUID(env) == ARM_CPUID_CORTEXA15) {
                        /* Linux wants the number of processors from here.
                         * Might as well set the interrupt-controller bit too.
                         */
                        return ((smp_cpus - 1) << 24) | (1 << 23);
                    }
                    return 0;
                case 3:
                    /* L2 cache extended control (A15) */
                    return 0;
                default:
                    goto bad_reg;
                }
            default:
                goto bad_reg;
            }
            break;
        case 12: /* Performance monitor control */
            if (!arm_feature(env, ARM_FEATURE_V7)) {
                goto bad_reg;
            }
            switch (op2) {
            case 0: /* performance monitor control register */
                return env->cp15.c9_pmcr;
            case 1: /* count enable set */
            case 2: /* count enable clear */
                return env->cp15.c9_pmcnten;
            case 3: /* overflow flag status */
                return env->cp15.c9_pmovsr;
            case 4: /* software increment */
            case 5: /* event counter selection register */
                return 0; /* Unimplemented, RAZ/WI */
            default:
                goto bad_reg;
            }
        case 13: /* Performance counters */
            if (!arm_feature(env, ARM_FEATURE_V7)) {
                goto bad_reg;
            }
            switch (op2) {
            case 1: /* Event type select */
                return env->cp15.c9_pmxevtyper;
            case 0: /* Cycle count register */
            case 2: /* Event count register */
                /* Unimplemented, so RAZ/WI */
                return 0;
            default:
                goto bad_reg;
            }
        case 14: /* Performance monitor control */
            if (!arm_feature(env, ARM_FEATURE_V7)) {
                goto bad_reg;
            }
            switch (op2) {
            case 0: /* user enable */
                return env->cp15.c9_pmuserenr;
            case 1: /* interrupt enable set */
            case 2: /* interrupt enable clear */
                return env->cp15.c9_pminten;
            default:
                goto bad_reg;
            }
        default:
            goto bad_reg;
        }
        break;
    case 10: /* MMU TLB lockdown.  */
        /* ??? TLB lockdown not implemented.  */
        return 0;
    case 11: /* TCM DMA control.  */
    case 12: /* Reserved.  */
        goto bad_reg;
    case 13: /* Process ID.  */
        switch (op2) {
        case 0:
            return env->cp15.c13_fcse;
        case 1:
            return env->cp15.c13_context;
        default:
            goto bad_reg;
        }
    case 14: /* Generic timer */
        if (arm_feature(env, ARM_FEATURE_GENERIC_TIMER)) {
            /* Dummy implementation: RAZ/WI for all */
            return 0;
        }
        goto bad_reg;
    case 15: /* Implementation specific.  */
        if (arm_feature(env, ARM_FEATURE_XSCALE)) {
            if (op2 == 0 && crm == 1)
                return env->cp15.c15_cpar;

            goto bad_reg;
        }
        if (arm_feature(env, ARM_FEATURE_OMAPCP)) {
            switch (crm) {
            case 0:
                return 0;
            case 1: /* Read TI925T configuration.  */
                return env->cp15.c15_ticonfig;
            case 2: /* Read I_max.  */
                return env->cp15.c15_i_max;
            case 3: /* Read I_min.  */
                return env->cp15.c15_i_min;
            case 4: /* Read thread-ID.  */
                return env->cp15.c15_threadid;
            case 8: /* TI925T_status */
                return 0;
            }
            /* TODO: Peripheral port remap register:
             * On OMAP2 mcr p15, 0, rn, c15, c2, 4 sets up the interrupt
             * controller base address at $rn & ~0xfff and map size of
             * 0x200 << ($rn & 0xfff), when MMU is off.  */
            goto bad_reg;
        }
        if (ARM_CPUID(env) == ARM_CPUID_CORTEXA9) {
            switch (crm) {
            case 0:
                if ((op1 == 4) && (op2 == 0)) {
                    /* The config_base_address should hold the value of
                     * the peripheral base. ARM should get this from a CPU
                     * object property, but that support isn't available in
                     * December 2011. Default to 0 for now and board models
                     * that care can set it by a private hook */
                    return env->cp15.c15_config_base_address;
                } else if ((op1 == 0) && (op2 == 0)) {
                    /* power_control should be set to maximum latency. Again,
                       default to 0 and set by private hook */
                    return env->cp15.c15_power_control;
                } else if ((op1 == 0) && (op2 == 1)) {
                    return env->cp15.c15_diagnostic;
                } else if ((op1 == 0) && (op2 == 2)) {
                    return env->cp15.c15_power_diagnostic;
                }
                break;
            case 1: /* NEON Busy */
                return 0;
            case 5: /* tlb lockdown */
            case 6:
            case 7:
                if ((op1 == 5) && (op2 == 2)) {
                    return 0;
                }
                break;
            default:
                break;
            }
            goto bad_reg;
        }
        return 0;
    }
bad_reg:
    /* ??? For debugging only.  Should raise illegal instruction exception.  */
    cpu_abort(env, "Unimplemented cp15 register read (c%d, c%d, {%d, %d})\n",
              (insn >> 16) & 0xf, crm, op1, op2);
    return 0;
}

void HELPER(set_r13_banked)(CPUARMState *env, uint32_t mode, uint32_t val)
{
    if ((env->uncached_cpsr & CPSR_M) == mode) {
        env->regs[13] = val;
    } else {
        env->banked_r13[bank_number(env, mode)] = val;
    }
}

uint32_t HELPER(get_r13_banked)(CPUARMState *env, uint32_t mode)
{
    if ((env->uncached_cpsr & CPSR_M) == mode) {
        return env->regs[13];
    } else {
        return env->banked_r13[bank_number(env, mode)];
    }
}

uint32_t HELPER(v7m_mrs)(CPUARMState *env, uint32_t reg)
{
    switch (reg) {
    case 0: /* APSR */
        return xpsr_read(env) & 0xf8000000;
    case 1: /* IAPSR */
        return xpsr_read(env) & 0xf80001ff;
    case 2: /* EAPSR */
        return xpsr_read(env) & 0xff00fc00;
    case 3: /* xPSR */
        return xpsr_read(env) & 0xff00fdff;
    case 5: /* IPSR */
        return xpsr_read(env) & 0x000001ff;
    case 6: /* EPSR */
        return xpsr_read(env) & 0x0700fc00;
    case 7: /* IEPSR */
        return xpsr_read(env) & 0x0700edff;
    case 8: /* MSP */
        return env->v7m.current_sp ? env->v7m.other_sp : env->regs[13];
    case 9: /* PSP */
        return env->v7m.current_sp ? env->regs[13] : env->v7m.other_sp;
    case 16: /* PRIMASK */
        return (env->uncached_cpsr & CPSR_I) != 0;
    case 17: /* BASEPRI */
    case 18: /* BASEPRI_MAX */
        return env->v7m.basepri;
    case 19: /* FAULTMASK */
        return (env->uncached_cpsr & CPSR_F) != 0;
    case 20: /* CONTROL */
        return env->v7m.control;
    default:
        /* ??? For debugging only.  */
        cpu_abort(env, "Unimplemented system register read (%d)\n", reg);
        return 0;
    }
}

void HELPER(v7m_msr)(CPUARMState *env, uint32_t reg, uint32_t val)
{
    switch (reg) {
    case 0: /* APSR */
        xpsr_write(env, val, 0xf8000000);
        break;
    case 1: /* IAPSR */
        xpsr_write(env, val, 0xf8000000);
        break;
    case 2: /* EAPSR */
        xpsr_write(env, val, 0xfe00fc00);
        break;
    case 3: /* xPSR */
        xpsr_write(env, val, 0xfe00fc00);
        break;
    case 5: /* IPSR */
        /* IPSR bits are readonly.  */
        break;
    case 6: /* EPSR */
        xpsr_write(env, val, 0x0600fc00);
        break;
    case 7: /* IEPSR */
        xpsr_write(env, val, 0x0600fc00);
        break;
    case 8: /* MSP */
        if (env->v7m.current_sp)
            env->v7m.other_sp = val;
        else
            env->regs[13] = val;
        break;
    case 9: /* PSP */
        if (env->v7m.current_sp)
            env->regs[13] = val;
        else
            env->v7m.other_sp = val;
        break;
    case 16: /* PRIMASK */
        if (val & 1)
            env->uncached_cpsr |= CPSR_I;
        else
            env->uncached_cpsr &= ~CPSR_I;
        break;
    case 17: /* BASEPRI */
        env->v7m.basepri = val & 0xff;
        break;
    case 18: /* BASEPRI_MAX */
        val &= 0xff;
        if (val != 0 && (val < env->v7m.basepri || env->v7m.basepri == 0))
            env->v7m.basepri = val;
        break;
    case 19: /* FAULTMASK */
        if (val & 1)
            env->uncached_cpsr |= CPSR_F;
        else
            env->uncached_cpsr &= ~CPSR_F;
        break;
    case 20: /* CONTROL */
        env->v7m.control = val & 3;
        switch_v7m_sp(env, (val & 2) != 0);
        break;
    default:
        /* ??? For debugging only.  */
        cpu_abort(env, "Unimplemented system register write (%d)\n", reg);
        return;
    }
}

#endif

/* Note that signed overflow is undefined in C.  The following routines are
   careful to use unsigned types where modulo arithmetic is required.
   Failure to do so _will_ break on newer gcc.  */

/* Signed saturating arithmetic.  */

/* Perform 16-bit signed saturating addition.  */
static inline uint16_t add16_sat(uint16_t a, uint16_t b)
{
    uint16_t res;

    res = a + b;
    if (((res ^ a) & 0x8000) && !((a ^ b) & 0x8000)) {
        if (a & 0x8000)
            res = 0x8000;
        else
            res = 0x7fff;
    }
    return res;
}

/* Perform 8-bit signed saturating addition.  */
static inline uint8_t add8_sat(uint8_t a, uint8_t b)
{
    uint8_t res;

    res = a + b;
    if (((res ^ a) & 0x80) && !((a ^ b) & 0x80)) {
        if (a & 0x80)
            res = 0x80;
        else
            res = 0x7f;
    }
    return res;
}

/* Perform 16-bit signed saturating subtraction.  */
static inline uint16_t sub16_sat(uint16_t a, uint16_t b)
{
    uint16_t res;

    res = a - b;
    if (((res ^ a) & 0x8000) && ((a ^ b) & 0x8000)) {
        if (a & 0x8000)
            res = 0x8000;
        else
            res = 0x7fff;
    }
    return res;
}

/* Perform 8-bit signed saturating subtraction.  */
static inline uint8_t sub8_sat(uint8_t a, uint8_t b)
{
    uint8_t res;

    res = a - b;
    if (((res ^ a) & 0x80) && ((a ^ b) & 0x80)) {
        if (a & 0x80)
            res = 0x80;
        else
            res = 0x7f;
    }
    return res;
}

#define ADD16(a, b, n) RESULT(add16_sat(a, b), n, 16);
#define SUB16(a, b, n) RESULT(sub16_sat(a, b), n, 16);
#define ADD8(a, b, n)  RESULT(add8_sat(a, b), n, 8);
#define SUB8(a, b, n)  RESULT(sub8_sat(a, b), n, 8);
#define PFX q

#include "op_addsub.h"

/* Unsigned saturating arithmetic.  */
static inline uint16_t add16_usat(uint16_t a, uint16_t b)
{
    uint16_t res;
    res = a + b;
    if (res < a)
        res = 0xffff;
    return res;
}

static inline uint16_t sub16_usat(uint16_t a, uint16_t b)
{
    if (a > b)
        return a - b;
    else
        return 0;
}

static inline uint8_t add8_usat(uint8_t a, uint8_t b)
{
    uint8_t res;
    res = a + b;
    if (res < a)
        res = 0xff;
    return res;
}

static inline uint8_t sub8_usat(uint8_t a, uint8_t b)
{
    if (a > b)
        return a - b;
    else
        return 0;
}

#define ADD16(a, b, n) RESULT(add16_usat(a, b), n, 16);
#define SUB16(a, b, n) RESULT(sub16_usat(a, b), n, 16);
#define ADD8(a, b, n)  RESULT(add8_usat(a, b), n, 8);
#define SUB8(a, b, n)  RESULT(sub8_usat(a, b), n, 8);
#define PFX uq

#include "op_addsub.h"

/* Signed modulo arithmetic.  */
#define SARITH16(a, b, n, op) do { \
    int32_t sum; \
    sum = (int32_t)(int16_t)(a) op (int32_t)(int16_t)(b); \
    RESULT(sum, n, 16); \
    if (sum >= 0) \
        ge |= 3 << (n * 2); \
    } while(0)

#define SARITH8(a, b, n, op) do { \
    int32_t sum; \
    sum = (int32_t)(int8_t)(a) op (int32_t)(int8_t)(b); \
    RESULT(sum, n, 8); \
    if (sum >= 0) \
        ge |= 1 << n; \
    } while(0)


#define ADD16(a, b, n) SARITH16(a, b, n, +)
#define SUB16(a, b, n) SARITH16(a, b, n, -)
#define ADD8(a, b, n)  SARITH8(a, b, n, +)
#define SUB8(a, b, n)  SARITH8(a, b, n, -)
#define PFX s
#define ARITH_GE

#include "op_addsub.h"

/* Unsigned modulo arithmetic.  */
#define ADD16(a, b, n) do { \
    uint32_t sum; \
    sum = (uint32_t)(uint16_t)(a) + (uint32_t)(uint16_t)(b); \
    RESULT(sum, n, 16); \
    if ((sum >> 16) == 1) \
        ge |= 3 << (n * 2); \
    } while(0)

#define ADD8(a, b, n) do { \
    uint32_t sum; \
    sum = (uint32_t)(uint8_t)(a) + (uint32_t)(uint8_t)(b); \
    RESULT(sum, n, 8); \
    if ((sum >> 8) == 1) \
        ge |= 1 << n; \
    } while(0)

#define SUB16(a, b, n) do { \
    uint32_t sum; \
    sum = (uint32_t)(uint16_t)(a) - (uint32_t)(uint16_t)(b); \
    RESULT(sum, n, 16); \
    if ((sum >> 16) == 0) \
        ge |= 3 << (n * 2); \
    } while(0)

#define SUB8(a, b, n) do { \
    uint32_t sum; \
    sum = (uint32_t)(uint8_t)(a) - (uint32_t)(uint8_t)(b); \
    RESULT(sum, n, 8); \
    if ((sum >> 8) == 0) \
        ge |= 1 << n; \
    } while(0)

#define PFX u
#define ARITH_GE

#include "op_addsub.h"

/* Halved signed arithmetic.  */
#define ADD16(a, b, n) \
  RESULT(((int32_t)(int16_t)(a) + (int32_t)(int16_t)(b)) >> 1, n, 16)
#define SUB16(a, b, n) \
  RESULT(((int32_t)(int16_t)(a) - (int32_t)(int16_t)(b)) >> 1, n, 16)
#define ADD8(a, b, n) \
  RESULT(((int32_t)(int8_t)(a) + (int32_t)(int8_t)(b)) >> 1, n, 8)
#define SUB8(a, b, n) \
  RESULT(((int32_t)(int8_t)(a) - (int32_t)(int8_t)(b)) >> 1, n, 8)
#define PFX sh

#include "op_addsub.h"

/* Halved unsigned arithmetic.  */
#define ADD16(a, b, n) \
  RESULT(((uint32_t)(uint16_t)(a) + (uint32_t)(uint16_t)(b)) >> 1, n, 16)
#define SUB16(a, b, n) \
  RESULT(((uint32_t)(uint16_t)(a) - (uint32_t)(uint16_t)(b)) >> 1, n, 16)
#define ADD8(a, b, n) \
  RESULT(((uint32_t)(uint8_t)(a) + (uint32_t)(uint8_t)(b)) >> 1, n, 8)
#define SUB8(a, b, n) \
  RESULT(((uint32_t)(uint8_t)(a) - (uint32_t)(uint8_t)(b)) >> 1, n, 8)
#define PFX uh

#include "op_addsub.h"

static inline uint8_t do_usad(uint8_t a, uint8_t b)
{
    if (a > b)
        return a - b;
    else
        return b - a;
}

/* Unsigned sum of absolute byte differences.  */
uint32_t HELPER(usad8)(uint32_t a, uint32_t b)
{
    uint32_t sum;
    sum = do_usad(a, b);
    sum += do_usad(a >> 8, b >> 8);
    sum += do_usad(a >> 16, b >>16);
    sum += do_usad(a >> 24, b >> 24);
    return sum;
}

/* For ARMv6 SEL instruction.  */
uint32_t HELPER(sel_flags)(uint32_t flags, uint32_t a, uint32_t b)
{
    uint32_t mask;

    mask = 0;
    if (flags & 1)
        mask |= 0xff;
    if (flags & 2)
        mask |= 0xff00;
    if (flags & 4)
        mask |= 0xff0000;
    if (flags & 8)
        mask |= 0xff000000;
    return (a & mask) | (b & ~mask);
}

uint32_t HELPER(logicq_cc)(uint64_t val)
{
    return (val >> 32) | (val != 0);
}

/* VFP support.  We follow the convention used for VFP instrunctions:
   Single precition routines have a "s" suffix, double precision a
   "d" suffix.  */

/* Convert host exception flags to vfp form.  */
static inline int vfp_exceptbits_from_host(int host_bits)
{
    int target_bits = 0;

    if (host_bits & float_flag_invalid)
        target_bits |= 1;
    if (host_bits & float_flag_divbyzero)
        target_bits |= 2;
    if (host_bits & float_flag_overflow)
        target_bits |= 4;
    if (host_bits & (float_flag_underflow | float_flag_output_denormal))
        target_bits |= 8;
    if (host_bits & float_flag_inexact)
        target_bits |= 0x10;
    if (host_bits & float_flag_input_denormal)
        target_bits |= 0x80;
    return target_bits;
}

uint32_t HELPER(vfp_get_fpscr)(CPUARMState *env)
{
    int i;
    uint32_t fpscr;

    fpscr = (env->vfp.xregs[ARM_VFP_FPSCR] & 0xffc8ffff)
            | (env->vfp.vec_len << 16)
            | (env->vfp.vec_stride << 20);
    i = get_float_exception_flags(&env->vfp.fp_status);
    i |= get_float_exception_flags(&env->vfp.standard_fp_status);
    fpscr |= vfp_exceptbits_from_host(i);
    return fpscr;
}

uint32_t vfp_get_fpscr(CPUARMState *env)
{
    return HELPER(vfp_get_fpscr)(env);
}

/* Convert vfp exception flags to target form.  */
static inline int vfp_exceptbits_to_host(int target_bits)
{
    int host_bits = 0;

    if (target_bits & 1)
        host_bits |= float_flag_invalid;
    if (target_bits & 2)
        host_bits |= float_flag_divbyzero;
    if (target_bits & 4)
        host_bits |= float_flag_overflow;
    if (target_bits & 8)
        host_bits |= float_flag_underflow;
    if (target_bits & 0x10)
        host_bits |= float_flag_inexact;
    if (target_bits & 0x80)
        host_bits |= float_flag_input_denormal;
    return host_bits;
}

void HELPER(vfp_set_fpscr)(CPUARMState *env, uint32_t val)
{
    int i;
    uint32_t changed;

    changed = env->vfp.xregs[ARM_VFP_FPSCR];
    env->vfp.xregs[ARM_VFP_FPSCR] = (val & 0xffc8ffff);
    env->vfp.vec_len = (val >> 16) & 7;
    env->vfp.vec_stride = (val >> 20) & 3;

    changed ^= val;
    if (changed & (3 << 22)) {
        i = (val >> 22) & 3;
        switch (i) {
        case 0:
            i = float_round_nearest_even;
            break;
        case 1:
            i = float_round_up;
            break;
        case 2:
            i = float_round_down;
            break;
        case 3:
            i = float_round_to_zero;
            break;
        }
        set_float_rounding_mode(i, &env->vfp.fp_status);
    }
    if (changed & (1 << 24)) {
        set_flush_to_zero((val & (1 << 24)) != 0, &env->vfp.fp_status);
        set_flush_inputs_to_zero((val & (1 << 24)) != 0, &env->vfp.fp_status);
    }
    if (changed & (1 << 25))
        set_default_nan_mode((val & (1 << 25)) != 0, &env->vfp.fp_status);

    i = vfp_exceptbits_to_host(val);
    set_float_exception_flags(i, &env->vfp.fp_status);
    set_float_exception_flags(0, &env->vfp.standard_fp_status);
}

void vfp_set_fpscr(CPUARMState *env, uint32_t val)
{
    HELPER(vfp_set_fpscr)(env, val);
}

#define VFP_HELPER(name, p) HELPER(glue(glue(vfp_,name),p))

#define VFP_BINOP(name) \
float32 VFP_HELPER(name, s)(float32 a, float32 b, void *fpstp) \
{ \
    float_status *fpst = fpstp; \
    return float32_ ## name(a, b, fpst); \
} \
float64 VFP_HELPER(name, d)(float64 a, float64 b, void *fpstp) \
{ \
    float_status *fpst = fpstp; \
    return float64_ ## name(a, b, fpst); \
}
VFP_BINOP(add)
VFP_BINOP(sub)
VFP_BINOP(mul)
VFP_BINOP(div)
#undef VFP_BINOP

float32 VFP_HELPER(neg, s)(float32 a)
{
    return float32_chs(a);
}

float64 VFP_HELPER(neg, d)(float64 a)
{
    return float64_chs(a);
}

float32 VFP_HELPER(abs, s)(float32 a)
{
    return float32_abs(a);
}

float64 VFP_HELPER(abs, d)(float64 a)
{
    return float64_abs(a);
}

float32 VFP_HELPER(sqrt, s)(float32 a, CPUARMState *env)
{
    return float32_sqrt(a, &env->vfp.fp_status);
}

float64 VFP_HELPER(sqrt, d)(float64 a, CPUARMState *env)
{
    return float64_sqrt(a, &env->vfp.fp_status);
}

/* XXX: check quiet/signaling case */
#define DO_VFP_cmp(p, type) \
void VFP_HELPER(cmp, p)(type a, type b, CPUARMState *env)  \
{ \
    uint32_t flags; \
    switch(type ## _compare_quiet(a, b, &env->vfp.fp_status)) { \
    case 0: flags = 0x6; break; \
    case -1: flags = 0x8; break; \
    case 1: flags = 0x2; break; \
    default: case 2: flags = 0x3; break; \
    } \
    env->vfp.xregs[ARM_VFP_FPSCR] = (flags << 28) \
        | (env->vfp.xregs[ARM_VFP_FPSCR] & 0x0fffffff); \
} \
void VFP_HELPER(cmpe, p)(type a, type b, CPUARMState *env) \
{ \
    uint32_t flags; \
    switch(type ## _compare(a, b, &env->vfp.fp_status)) { \
    case 0: flags = 0x6; break; \
    case -1: flags = 0x8; break; \
    case 1: flags = 0x2; break; \
    default: case 2: flags = 0x3; break; \
    } \
    env->vfp.xregs[ARM_VFP_FPSCR] = (flags << 28) \
        | (env->vfp.xregs[ARM_VFP_FPSCR] & 0x0fffffff); \
}
DO_VFP_cmp(s, float32)
DO_VFP_cmp(d, float64)
#undef DO_VFP_cmp

/* Integer to float and float to integer conversions */

#define CONV_ITOF(name, fsz, sign) \
    float##fsz HELPER(name)(uint32_t x, void *fpstp) \
{ \
    float_status *fpst = fpstp; \
    return sign##int32_to_##float##fsz((sign##int32_t)x, fpst); \
}

#define CONV_FTOI(name, fsz, sign, round) \
uint32_t HELPER(name)(float##fsz x, void *fpstp) \
{ \
    float_status *fpst = fpstp; \
    if (float##fsz##_is_any_nan(x)) { \
        float_raise(float_flag_invalid, fpst); \
        return 0; \
    } \
    return float##fsz##_to_##sign##int32##round(x, fpst); \
}

#define FLOAT_CONVS(name, p, fsz, sign) \
CONV_ITOF(vfp_##name##to##p, fsz, sign) \
CONV_FTOI(vfp_to##name##p, fsz, sign, ) \
CONV_FTOI(vfp_to##name##z##p, fsz, sign, _round_to_zero)

FLOAT_CONVS(si, s, 32, )
FLOAT_CONVS(si, d, 64, )
FLOAT_CONVS(ui, s, 32, u)
FLOAT_CONVS(ui, d, 64, u)

#undef CONV_ITOF
#undef CONV_FTOI
#undef FLOAT_CONVS

/* floating point conversion */
float64 VFP_HELPER(fcvtd, s)(float32 x, CPUARMState *env)
{
    float64 r = float32_to_float64(x, &env->vfp.fp_status);
    /* ARM requires that S<->D conversion of any kind of NaN generates
     * a quiet NaN by forcing the most significant frac bit to 1.
     */
    return float64_maybe_silence_nan(r);
}

float32 VFP_HELPER(fcvts, d)(float64 x, CPUARMState *env)
{
    float32 r =  float64_to_float32(x, &env->vfp.fp_status);
    /* ARM requires that S<->D conversion of any kind of NaN generates
     * a quiet NaN by forcing the most significant frac bit to 1.
     */
    return float32_maybe_silence_nan(r);
}

/* VFP3 fixed point conversion.  */
#define VFP_CONV_FIX(name, p, fsz, itype, sign) \
float##fsz HELPER(vfp_##name##to##p)(uint##fsz##_t  x, uint32_t shift, \
                                    void *fpstp) \
{ \
    float_status *fpst = fpstp; \
    float##fsz tmp; \
    tmp = sign##int32_to_##float##fsz((itype##_t)x, fpst); \
    return float##fsz##_scalbn(tmp, -(int)shift, fpst); \
} \
uint##fsz##_t HELPER(vfp_to##name##p)(float##fsz x, uint32_t shift, \
                                       void *fpstp) \
{ \
    float_status *fpst = fpstp; \
    float##fsz tmp; \
    if (float##fsz##_is_any_nan(x)) { \
        float_raise(float_flag_invalid, fpst); \
        return 0; \
    } \
    tmp = float##fsz##_scalbn(x, shift, fpst); \
    return float##fsz##_to_##itype##_round_to_zero(tmp, fpst); \
}

VFP_CONV_FIX(sh, d, 64, int16, )
VFP_CONV_FIX(sl, d, 64, int32, )
VFP_CONV_FIX(uh, d, 64, uint16, u)
VFP_CONV_FIX(ul, d, 64, uint32, u)
VFP_CONV_FIX(sh, s, 32, int16, )
VFP_CONV_FIX(sl, s, 32, int32, )
VFP_CONV_FIX(uh, s, 32, uint16, u)
VFP_CONV_FIX(ul, s, 32, uint32, u)
#undef VFP_CONV_FIX

/* Half precision conversions.  */
static float32 do_fcvt_f16_to_f32(uint32_t a, CPUARMState *env, float_status *s)
{
    int ieee = (env->vfp.xregs[ARM_VFP_FPSCR] & (1 << 26)) == 0;
    float32 r = float16_to_float32(make_float16(a), ieee, s);
    if (ieee) {
        return float32_maybe_silence_nan(r);
    }
    return r;
}

static uint32_t do_fcvt_f32_to_f16(float32 a, CPUARMState *env, float_status *s)
{
    int ieee = (env->vfp.xregs[ARM_VFP_FPSCR] & (1 << 26)) == 0;
    float16 r = float32_to_float16(a, ieee, s);
    if (ieee) {
        r = float16_maybe_silence_nan(r);
    }
    return float16_val(r);
}

float32 HELPER(neon_fcvt_f16_to_f32)(uint32_t a, CPUARMState *env)
{
    return do_fcvt_f16_to_f32(a, env, &env->vfp.standard_fp_status);
}

uint32_t HELPER(neon_fcvt_f32_to_f16)(float32 a, CPUARMState *env)
{
    return do_fcvt_f32_to_f16(a, env, &env->vfp.standard_fp_status);
}

float32 HELPER(vfp_fcvt_f16_to_f32)(uint32_t a, CPUARMState *env)
{
    return do_fcvt_f16_to_f32(a, env, &env->vfp.fp_status);
}

uint32_t HELPER(vfp_fcvt_f32_to_f16)(float32 a, CPUARMState *env)
{
    return do_fcvt_f32_to_f16(a, env, &env->vfp.fp_status);
}

#define float32_two make_float32(0x40000000)
#define float32_three make_float32(0x40400000)
#define float32_one_point_five make_float32(0x3fc00000)

float32 HELPER(recps_f32)(float32 a, float32 b, CPUARMState *env)
{
    float_status *s = &env->vfp.standard_fp_status;
    if ((float32_is_infinity(a) && float32_is_zero_or_denormal(b)) ||
        (float32_is_infinity(b) && float32_is_zero_or_denormal(a))) {
        if (!(float32_is_zero(a) || float32_is_zero(b))) {
            float_raise(float_flag_input_denormal, s);
        }
        return float32_two;
    }
    return float32_sub(float32_two, float32_mul(a, b, s), s);
}

float32 HELPER(rsqrts_f32)(float32 a, float32 b, CPUARMState *env)
{
    float_status *s = &env->vfp.standard_fp_status;
    float32 product;
    if ((float32_is_infinity(a) && float32_is_zero_or_denormal(b)) ||
        (float32_is_infinity(b) && float32_is_zero_or_denormal(a))) {
        if (!(float32_is_zero(a) || float32_is_zero(b))) {
            float_raise(float_flag_input_denormal, s);
        }
        return float32_one_point_five;
    }
    product = float32_mul(a, b, s);
    return float32_div(float32_sub(float32_three, product, s), float32_two, s);
}

/* NEON helpers.  */

/* Constants 256 and 512 are used in some helpers; we avoid relying on
 * int->float conversions at run-time.  */
#define float64_256 make_float64(0x4070000000000000LL)
#define float64_512 make_float64(0x4080000000000000LL)

/* The algorithm that must be used to calculate the estimate
 * is specified by the ARM ARM.
 */
static float64 recip_estimate(float64 a, CPUARMState *env)
{
    /* These calculations mustn't set any fp exception flags,
     * so we use a local copy of the fp_status.
     */
    float_status dummy_status = env->vfp.standard_fp_status;
    float_status *s = &dummy_status;
    /* q = (int)(a * 512.0) */
    float64 q = float64_mul(float64_512, a, s);
    int64_t q_int = float64_to_int64_round_to_zero(q, s);

    /* r = 1.0 / (((double)q + 0.5) / 512.0) */
    q = int64_to_float64(q_int, s);
    q = float64_add(q, float64_half, s);
    q = float64_div(q, float64_512, s);
    q = float64_div(float64_one, q, s);

    /* s = (int)(256.0 * r + 0.5) */
    q = float64_mul(q, float64_256, s);
    q = float64_add(q, float64_half, s);
    q_int = float64_to_int64_round_to_zero(q, s);

    /* return (double)s / 256.0 */
    return float64_div(int64_to_float64(q_int, s), float64_256, s);
}

float32 HELPER(recpe_f32)(float32 a, CPUARMState *env)
{
    float_status *s = &env->vfp.standard_fp_status;
    float64 f64;
    uint32_t val32 = float32_val(a);

    int result_exp;
    int a_exp = (val32  & 0x7f800000) >> 23;
    int sign = val32 & 0x80000000;

    if (float32_is_any_nan(a)) {
        if (float32_is_signaling_nan(a)) {
            float_raise(float_flag_invalid, s);
        }
        return float32_default_nan;
    } else if (float32_is_infinity(a)) {
        return float32_set_sign(float32_zero, float32_is_neg(a));
    } else if (float32_is_zero_or_denormal(a)) {
        if (!float32_is_zero(a)) {
            float_raise(float_flag_input_denormal, s);
        }
        float_raise(float_flag_divbyzero, s);
        return float32_set_sign(float32_infinity, float32_is_neg(a));
    } else if (a_exp >= 253) {
        float_raise(float_flag_underflow, s);
        return float32_set_sign(float32_zero, float32_is_neg(a));
    }

    f64 = make_float64((0x3feULL << 52)
                       | ((int64_t)(val32 & 0x7fffff) << 29));

    result_exp = 253 - a_exp;

    f64 = recip_estimate(f64, env);

    val32 = sign
        | ((result_exp & 0xff) << 23)
        | ((float64_val(f64) >> 29) & 0x7fffff);
    return make_float32(val32);
}

/* The algorithm that must be used to calculate the estimate
 * is specified by the ARM ARM.
 */
static float64 recip_sqrt_estimate(float64 a, CPUARMState *env)
{
    /* These calculations mustn't set any fp exception flags,
     * so we use a local copy of the fp_status.
     */
    float_status dummy_status = env->vfp.standard_fp_status;
    float_status *s = &dummy_status;
    float64 q;
    int64_t q_int;

    if (float64_lt(a, float64_half, s)) {
        /* range 0.25 <= a < 0.5 */

        /* a in units of 1/512 rounded down */
        /* q0 = (int)(a * 512.0);  */
        q = float64_mul(float64_512, a, s);
        q_int = float64_to_int64_round_to_zero(q, s);

        /* reciprocal root r */
        /* r = 1.0 / sqrt(((double)q0 + 0.5) / 512.0);  */
        q = int64_to_float64(q_int, s);
        q = float64_add(q, float64_half, s);
        q = float64_div(q, float64_512, s);
        q = float64_sqrt(q, s);
        q = float64_div(float64_one, q, s);
    } else {
        /* range 0.5 <= a < 1.0 */

        /* a in units of 1/256 rounded down */
        /* q1 = (int)(a * 256.0); */
        q = float64_mul(float64_256, a, s);
        int64_t q_int = float64_to_int64_round_to_zero(q, s);

        /* reciprocal root r */
        /* r = 1.0 /sqrt(((double)q1 + 0.5) / 256); */
        q = int64_to_float64(q_int, s);
        q = float64_add(q, float64_half, s);
        q = float64_div(q, float64_256, s);
        q = float64_sqrt(q, s);
        q = float64_div(float64_one, q, s);
    }
    /* r in units of 1/256 rounded to nearest */
    /* s = (int)(256.0 * r + 0.5); */

    q = float64_mul(q, float64_256,s );
    q = float64_add(q, float64_half, s);
    q_int = float64_to_int64_round_to_zero(q, s);

    /* return (double)s / 256.0;*/
    return float64_div(int64_to_float64(q_int, s), float64_256, s);
}

float32 HELPER(rsqrte_f32)(float32 a, CPUARMState *env)
{
    float_status *s = &env->vfp.standard_fp_status;
    int result_exp;
    float64 f64;
    uint32_t val;
    uint64_t val64;

    val = float32_val(a);

    if (float32_is_any_nan(a)) {
        if (float32_is_signaling_nan(a)) {
            float_raise(float_flag_invalid, s);
        }
        return float32_default_nan;
    } else if (float32_is_zero_or_denormal(a)) {
        if (!float32_is_zero(a)) {
            float_raise(float_flag_input_denormal, s);
        }
        float_raise(float_flag_divbyzero, s);
        return float32_set_sign(float32_infinity, float32_is_neg(a));
    } else if (float32_is_neg(a)) {
        float_raise(float_flag_invalid, s);
        return float32_default_nan;
    } else if (float32_is_infinity(a)) {
        return float32_zero;
    }

    /* Normalize to a double-precision value between 0.25 and 1.0,
     * preserving the parity of the exponent.  */
    if ((val & 0x800000) == 0) {
        f64 = make_float64(((uint64_t)(val & 0x80000000) << 32)
                           | (0x3feULL << 52)
                           | ((uint64_t)(val & 0x7fffff) << 29));
    } else {
        f64 = make_float64(((uint64_t)(val & 0x80000000) << 32)
                           | (0x3fdULL << 52)
                           | ((uint64_t)(val & 0x7fffff) << 29));
    }

    result_exp = (380 - ((val & 0x7f800000) >> 23)) / 2;

    f64 = recip_sqrt_estimate(f64, env);

    val64 = float64_val(f64);

    val = ((result_exp & 0xff) << 23)
        | ((val64 >> 29)  & 0x7fffff);
    return make_float32(val);
}

uint32_t HELPER(recpe_u32)(uint32_t a, CPUARMState *env)
{
    float64 f64;

    if ((a & 0x80000000) == 0) {
        return 0xffffffff;
    }

    f64 = make_float64((0x3feULL << 52)
                       | ((int64_t)(a & 0x7fffffff) << 21));

    f64 = recip_estimate (f64, env);

    return 0x80000000 | ((float64_val(f64) >> 21) & 0x7fffffff);
}

uint32_t HELPER(rsqrte_u32)(uint32_t a, CPUARMState *env)
{
    float64 f64;

    if ((a & 0xc0000000) == 0) {
        return 0xffffffff;
    }

    if (a & 0x80000000) {
        f64 = make_float64((0x3feULL << 52)
                           | ((uint64_t)(a & 0x7fffffff) << 21));
    } else { /* bits 31-30 == '01' */
        f64 = make_float64((0x3fdULL << 52)
                           | ((uint64_t)(a & 0x3fffffff) << 22));
    }

    f64 = recip_sqrt_estimate(f64, env);

    return 0x80000000 | ((float64_val(f64) >> 21) & 0x7fffffff);
}

/* VFPv4 fused multiply-accumulate */
float32 VFP_HELPER(muladd, s)(float32 a, float32 b, float32 c, void *fpstp)
{
    float_status *fpst = fpstp;
    return float32_muladd(a, b, c, 0, fpst);
}

float64 VFP_HELPER(muladd, d)(float64 a, float64 b, float64 c, void *fpstp)
{
    float_status *fpst = fpstp;
    return float64_muladd(a, b, c, 0, fpst);
}