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 "helpers.h"
  21
  22 #if defined(CONFIG_USER_ONLY)
  23
  24 void do_interrupt(CPUM68KState *env)
  25 {
  26     env->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 "softmmu_exec.h"
  38
  39 #define MMUSUFFIX _mmu
  40
  41 #define SHIFT 0
  42 #include "softmmu_template.h"
  43
  44 #define SHIFT 1
  45 #include "softmmu_template.h"
  46
  47 #define SHIFT 2
  48 #include "softmmu_template.h"
  49
  50 #define SHIFT 3
  51 #include "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(CPUM68KState *env, target_ulong addr, int is_write, int mmu_idx,
  57               uintptr_t retaddr)
  58 {
  59     int ret;
  60
  61     ret = cpu_m68k_handle_mmu_fault(env, addr, is_write, mmu_idx);
  62     if (unlikely(ret)) {
  63         if (retaddr) {
  64             /* now we have a real cpu fault */
  65             cpu_restore_state(env, retaddr);
  66         }
  67         cpu_loop_exit(env);
  68     }
  69 }
  70
  71 static void do_rte(CPUM68KState *env)
  72 {
  73     uint32_t sp;
  74     uint32_t fmt;
  75
  76     sp = env->aregs[7];
  77     fmt = cpu_ldl_kernel(env, sp);
  78     env->pc = cpu_ldl_kernel(env, sp + 4);
  79     sp |= (fmt >> 28) & 3;
  80     env->sr = fmt & 0xffff;
  81     m68k_switch_sp(env);
  82     env->aregs[7] = sp + 8;
  83 }
  84
  85 static void do_interrupt_all(CPUM68KState *env, int is_hw)
  86 {
  87     uint32_t sp;
  88     uint32_t fmt;
  89     uint32_t retaddr;
  90     uint32_t vector;
  91
  92     fmt = 0;
  93     retaddr = env->pc;
  94
  95     if (!is_hw) {
  96         switch (env->exception_index) {
  97         case EXCP_RTE:
  98             /* Return from an exception.  */
  99             do_rte(env);
 100             return;
 101         case EXCP_HALT_INSN:
 102             if (semihosting_enabled
 103                     && (env->sr & SR_S) != 0
 104                     && (env->pc & 3) == 0
 105                     && cpu_lduw_code(env, env->pc - 4) == 0x4e71
 106                     && cpu_ldl_code(env, env->pc) == 0x4e7bf000) {
 107                 env->pc += 4;
 108                 do_m68k_semihosting(env, env->dregs[0]);
 109                 return;
 110             }
 111             env->halted = 1;
 112             env->exception_index = EXCP_HLT;
 113             cpu_loop_exit(env);
 114             return;
 115         }
 116         if (env->exception_index >= EXCP_TRAP0
 117             && env->exception_index <= EXCP_TRAP15) {
 118             /* Move the PC after the trap instruction.  */
 119             retaddr += 2;
 120         }
 121     }
 122
 123     vector = env->exception_index << 2;
 124
 125     sp = env->aregs[7];
 126
 127     fmt |= 0x40000000;
 128     fmt |= (sp & 3) << 28;
 129     fmt |= vector << 16;
 130     fmt |= env->sr;
 131
 132     env->sr |= SR_S;
 133     if (is_hw) {
 134         env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
 135         env->sr &= ~SR_M;
 136     }
 137     m68k_switch_sp(env);
 138
 139     /* ??? This could cause MMU faults.  */
 140     sp &= ~3;
 141     sp -= 4;
 142     cpu_stl_kernel(env, sp, retaddr);
 143     sp -= 4;
 144     cpu_stl_kernel(env, sp, fmt);
 145     env->aregs[7] = sp;
 146     /* Jump to vector.  */
 147     env->pc = cpu_ldl_kernel(env, env->vbr + vector);
 148 }
 149
 150 void do_interrupt(CPUM68KState *env)
 151 {
 152     do_interrupt_all(env, 0);
 153 }
 154
 155 void do_interrupt_m68k_hardirq(CPUM68KState *env)
 156 {
 157     do_interrupt_all(env, 1);
 158 }
 159 #endif
 160
 161 static void raise_exception(CPUM68KState *env, int tt)
 162 {
 163     env->exception_index = tt;
 164     cpu_loop_exit(env);
 165 }
 166
 167 void HELPER(raise_exception)(CPUM68KState *env, uint32_t tt)
 168 {
 169     raise_exception(env, tt);
 170 }
 171
 172 void HELPER(divu)(CPUM68KState *env, uint32_t word)
 173 {
 174     uint32_t num;
 175     uint32_t den;
 176     uint32_t quot;
 177     uint32_t rem;
 178     uint32_t flags;
 179
 180     num = env->div1;
 181     den = env->div2;
 182     /* ??? This needs to make sure the throwing location is accurate.  */
 183     if (den == 0) {
 184         raise_exception(env, EXCP_DIV0);
 185     }
 186     quot = num / den;
 187     rem = num % den;
 188     flags = 0;
 189     if (word && quot > 0xffff)
 190         flags |= CCF_V;
 191     if (quot == 0)
 192         flags |= CCF_Z;
 193     else if ((int32_t)quot < 0)
 194         flags |= CCF_N;
 195     env->div1 = quot;
 196     env->div2 = rem;
 197     env->cc_dest = flags;
 198 }
 199
 200 void HELPER(divs)(CPUM68KState *env, uint32_t word)
 201 {
 202     int32_t num;
 203     int32_t den;
 204     int32_t quot;
 205     int32_t rem;
 206     int32_t flags;
 207
 208     num = env->div1;
 209     den = env->div2;
 210     if (den == 0) {
 211         raise_exception(env, EXCP_DIV0);
 212     }
 213     quot = num / den;
 214     rem = num % den;
 215     flags = 0;
 216     if (word && quot != (int16_t)quot)
 217         flags |= CCF_V;
 218     if (quot == 0)
 219         flags |= CCF_Z;
 220     else if (quot < 0)
 221         flags |= CCF_N;
 222     env->div1 = quot;
 223     env->div2 = rem;
 224     env->cc_dest = flags;
 225 }