target-m68k/op_helper.c

   1 /*
   2  *  M68K helper routines
   3  *
   4  *  Copyright (c) 2007 CodeSourcery
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #include "cpu.h"
  20 #include "helper.h"
  21
  22 #if defined(CONFIG_USER_ONLY)
  23
  24 void m68k_cpu_do_interrupt(CPUState *cs)
  25 {
  26     cs->exception_index = -1;
  27 }
  28
  29 void do_interrupt_m68k_hardirq(CPUM68KState *env)
  30 {
  31 }
  32
  33 #else
  34
  35 extern int semihosting_enabled;
  36
  37 #include "exec/softmmu_exec.h"
  38
  39 #define MMUSUFFIX _mmu
  40
  41 #define SHIFT 0
  42 #include "exec/softmmu_template.h"
  43
  44 #define SHIFT 1
  45 #include "exec/softmmu_template.h"
  46
  47 #define SHIFT 2
  48 #include "exec/softmmu_template.h"
  49
  50 #define SHIFT 3
  51 #include "exec/softmmu_template.h"
  52
  53 /* Try to fill the TLB and return an exception if error. If retaddr is
  54    NULL, it means that the function was called in C code (i.e. not
  55    from generated code or from helper.c) */
  56 void tlb_fill(CPUState *cs, target_ulong addr, int is_write, int mmu_idx,
  57               uintptr_t retaddr)
  58 {
  59     int ret;
  60
  61     ret = m68k_cpu_handle_mmu_fault(cs, addr, is_write, mmu_idx);
  62     if (unlikely(ret)) {
  63         M68kCPU *cpu = M68K_CPU(cs);
  64         CPUM68KState *env = &cpu->env;
  65
  66         if (retaddr) {
  67             /* now we have a real cpu fault */
  68             cpu_restore_state(env, retaddr);
  69         }
  70         cpu_loop_exit(cs);
  71     }
  72 }
  73
  74 static void do_rte(CPUM68KState *env)
  75 {
  76     uint32_t sp;
  77     uint32_t fmt;
  78
  79     sp = env->aregs[7];
  80     fmt = cpu_ldl_kernel(env, sp);
  81     env->pc = cpu_ldl_kernel(env, sp + 4);
  82     sp |= (fmt >> 28) & 3;
  83     env->sr = fmt & 0xffff;
  84     m68k_switch_sp(env);
  85     env->aregs[7] = sp + 8;
  86 }
  87
  88 static void do_interrupt_all(CPUM68KState *env, int is_hw)
  89 {
  90     CPUState *cs = CPU(m68k_env_get_cpu(env));
  91     uint32_t sp;
  92     uint32_t fmt;
  93     uint32_t retaddr;
  94     uint32_t vector;
  95
  96     fmt = 0;
  97     retaddr = env->pc;
  98
  99     if (!is_hw) {
 100         switch (cs->exception_index) {
 101         case EXCP_RTE:
 102             /* Return from an exception.  */
 103             do_rte(env);
 104             return;
 105         case EXCP_HALT_INSN:
 106             if (semihosting_enabled
 107                     && (env->sr & SR_S) != 0
 108                     && (env->pc & 3) == 0
 109                     && cpu_lduw_code(env, env->pc - 4) == 0x4e71
 110                     && cpu_ldl_code(env, env->pc) == 0x4e7bf000) {
 111                 env->pc += 4;
 112                 do_m68k_semihosting(env, env->dregs[0]);
 113                 return;
 114             }
 115             cs->halted = 1;
 116             cs->exception_index = EXCP_HLT;
 117             cpu_loop_exit(cs);
 118             return;
 119         }
 120         if (cs->exception_index >= EXCP_TRAP0
 121             && cs->exception_index <= EXCP_TRAP15) {
 122             /* Move the PC after the trap instruction.  */
 123             retaddr += 2;
 124         }
 125     }
 126
 127     vector = cs->exception_index << 2;
 128
 129     sp = env->aregs[7];
 130
 131     fmt |= 0x40000000;
 132     fmt |= (sp & 3) << 28;
 133     fmt |= vector << 16;
 134     fmt |= env->sr;
 135
 136     env->sr |= SR_S;
 137     if (is_hw) {
 138         env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
 139         env->sr &= ~SR_M;
 140     }
 141     m68k_switch_sp(env);
 142
 143     /* ??? This could cause MMU faults.  */
 144     sp &= ~3;
 145     sp -= 4;
 146     cpu_stl_kernel(env, sp, retaddr);
 147     sp -= 4;
 148     cpu_stl_kernel(env, sp, fmt);
 149     env->aregs[7] = sp;
 150     /* Jump to vector.  */
 151     env->pc = cpu_ldl_kernel(env, env->vbr + vector);
 152 }
 153
 154 void m68k_cpu_do_interrupt(CPUState *cs)
 155 {
 156     M68kCPU *cpu = M68K_CPU(cs);
 157     CPUM68KState *env = &cpu->env;
 158
 159     do_interrupt_all(env, 0);
 160 }
 161
 162 void do_interrupt_m68k_hardirq(CPUM68KState *env)
 163 {
 164     do_interrupt_all(env, 1);
 165 }
 166 #endif
 167
 168 static void raise_exception(CPUM68KState *env, int tt)
 169 {
 170     CPUState *cs = CPU(m68k_env_get_cpu(env));
 171
 172     cs->exception_index = tt;
 173     cpu_loop_exit(cs);
 174 }
 175
 176 void HELPER(raise_exception)(CPUM68KState *env, uint32_t tt)
 177 {
 178     raise_exception(env, tt);
 179 }
 180
 181 void HELPER(divu)(CPUM68KState *env, uint32_t word)
 182 {
 183     uint32_t num;
 184     uint32_t den;
 185     uint32_t quot;
 186     uint32_t rem;
 187     uint32_t flags;
 188
 189     num = env->div1;
 190     den = env->div2;
 191     /* ??? This needs to make sure the throwing location is accurate.  */
 192     if (den == 0) {
 193         raise_exception(env, EXCP_DIV0);
 194     }
 195     quot = num / den;
 196     rem = num % den;
 197     flags = 0;
 198     if (word && quot > 0xffff)
 199         flags |= CCF_V;
 200     if (quot == 0)
 201         flags |= CCF_Z;
 202     else if ((int32_t)quot < 0)
 203         flags |= CCF_N;
 204     env->div1 = quot;
 205     env->div2 = rem;
 206     env->cc_dest = flags;
 207 }
 208
 209 void HELPER(divs)(CPUM68KState *env, uint32_t word)
 210 {
 211     int32_t num;
 212     int32_t den;
 213     int32_t quot;
 214     int32_t rem;
 215     int32_t flags;
 216
 217     num = env->div1;
 218     den = env->div2;
 219     if (den == 0) {
 220         raise_exception(env, EXCP_DIV0);
 221     }
 222     quot = num / den;
 223     rem = num % den;
 224     flags = 0;
 225     if (word && quot != (int16_t)quot)
 226         flags |= CCF_V;
 227     if (quot == 0)
 228         flags |= CCF_Z;
 229     else if (quot < 0)
 230         flags |= CCF_N;
 231     env->div1 = quot;
 232     env->div2 = rem;
 233     env->cc_dest = flags;
 234 }