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     TranslationBlock *tb;
  60     int ret;
  61
  62     ret = cpu_m68k_handle_mmu_fault(env, addr, is_write, mmu_idx);
  63     if (unlikely(ret)) {
  64         if (retaddr) {
  65             /* now we have a real cpu fault */
  66             tb = tb_find_pc(retaddr);
  67             if (tb) {
  68                 /* the PC is inside the translated code. It means that we have
  69                    a virtual CPU fault */
  70                 cpu_restore_state(tb, env, retaddr);
  71             }
  72         }
  73         cpu_loop_exit(env);
  74     }
  75 }
  76
  77 static void do_rte(CPUM68KState *env)
  78 {
  79     uint32_t sp;
  80     uint32_t fmt;
  81
  82     sp = env->aregs[7];
  83     fmt = cpu_ldl_kernel(env, sp);
  84     env->pc = cpu_ldl_kernel(env, sp + 4);
  85     sp |= (fmt >> 28) & 3;
  86     env->sr = fmt & 0xffff;
  87     m68k_switch_sp(env);
  88     env->aregs[7] = sp + 8;
  89 }
  90
  91 static void do_interrupt_all(CPUM68KState *env, int is_hw)
  92 {
  93     uint32_t sp;
  94     uint32_t fmt;
  95     uint32_t retaddr;
  96     uint32_t vector;
  97
  98     fmt = 0;
  99     retaddr = env->pc;
 100
 101     if (!is_hw) {
 102         switch (env->exception_index) {
 103         case EXCP_RTE:
 104             /* Return from an exception.  */
 105             do_rte(env);
 106             return;
 107         case EXCP_HALT_INSN:
 108             if (semihosting_enabled
 109                     && (env->sr & SR_S) != 0
 110                     && (env->pc & 3) == 0
 111                     && cpu_lduw_code(env, env->pc - 4) == 0x4e71
 112                     && cpu_ldl_code(env, env->pc) == 0x4e7bf000) {
 113                 env->pc += 4;
 114                 do_m68k_semihosting(env, env->dregs[0]);
 115                 return;
 116             }
 117             env->halted = 1;
 118             env->exception_index = EXCP_HLT;
 119             cpu_loop_exit(env);
 120             return;
 121         }
 122         if (env->exception_index >= EXCP_TRAP0
 123             && env->exception_index <= EXCP_TRAP15) {
 124             /* Move the PC after the trap instruction.  */
 125             retaddr += 2;
 126         }
 127     }
 128
 129     vector = env->exception_index << 2;
 130
 131     sp = env->aregs[7];
 132
 133     fmt |= 0x40000000;
 134     fmt |= (sp & 3) << 28;
 135     fmt |= vector << 16;
 136     fmt |= env->sr;
 137
 138     env->sr |= SR_S;
 139     if (is_hw) {
 140         env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
 141         env->sr &= ~SR_M;
 142     }
 143     m68k_switch_sp(env);
 144
 145     /* ??? This could cause MMU faults.  */
 146     sp &= ~3;
 147     sp -= 4;
 148     cpu_stl_kernel(env, sp, retaddr);
 149     sp -= 4;
 150     cpu_stl_kernel(env, sp, fmt);
 151     env->aregs[7] = sp;
 152     /* Jump to vector.  */
 153     env->pc = cpu_ldl_kernel(env, env->vbr + vector);
 154 }
 155
 156 void do_interrupt(CPUM68KState *env)
 157 {
 158     do_interrupt_all(env, 0);
 159 }
 160
 161 void do_interrupt_m68k_hardirq(CPUM68KState *env)
 162 {
 163     do_interrupt_all(env, 1);
 164 }
 165 #endif
 166
 167 static void raise_exception(CPUM68KState *env, int tt)
 168 {
 169     env->exception_index = tt;
 170     cpu_loop_exit(env);
 171 }
 172
 173 void HELPER(raise_exception)(CPUM68KState *env, uint32_t tt)
 174 {
 175     raise_exception(env, tt);
 176 }
 177
 178 void HELPER(divu)(CPUM68KState *env, uint32_t word)
 179 {
 180     uint32_t num;
 181     uint32_t den;
 182     uint32_t quot;
 183     uint32_t rem;
 184     uint32_t flags;
 185
 186     num = env->div1;
 187     den = env->div2;
 188     /* ??? This needs to make sure the throwing location is accurate.  */
 189     if (den == 0) {
 190         raise_exception(env, EXCP_DIV0);
 191     }
 192     quot = num / den;
 193     rem = num % den;
 194     flags = 0;
 195     if (word && quot > 0xffff)
 196         flags |= CCF_V;
 197     if (quot == 0)
 198         flags |= CCF_Z;
 199     else if ((int32_t)quot < 0)
 200         flags |= CCF_N;
 201     env->div1 = quot;
 202     env->div2 = rem;
 203     env->cc_dest = flags;
 204 }
 205
 206 void HELPER(divs)(CPUM68KState *env, uint32_t word)
 207 {
 208     int32_t num;
 209     int32_t den;
 210     int32_t quot;
 211     int32_t rem;
 212     int32_t flags;
 213
 214     num = env->div1;
 215     den = env->div2;
 216     if (den == 0) {
 217         raise_exception(env, EXCP_DIV0);
 218     }
 219     quot = num / den;
 220     rem = num % den;
 221     flags = 0;
 222     if (word && quot != (int16_t)quot)
 223         flags |= CCF_V;
 224     if (quot == 0)
 225         flags |= CCF_Z;
 226     else if (quot < 0)
 227         flags |= CCF_N;
 228     env->div1 = quot;
 229     env->div2 = rem;
 230     env->cc_dest = flags;
 231 }