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 "dyngen-exec.h"
  21 #include "helpers.h"
  22
  23 #if defined(CONFIG_USER_ONLY)
  24
  25 void do_interrupt(CPUM68KState *env1)
  26 {
  27     env1->exception_index = -1;
  28 }
  29
  30 void do_interrupt_m68k_hardirq(CPUM68KState *env1)
  31 {
  32 }
  33
  34 #else
  35
  36 extern int semihosting_enabled;
  37
  38 #include "softmmu_exec.h"
  39
  40 #define MMUSUFFIX _mmu
  41
  42 #define SHIFT 0
  43 #include "softmmu_template.h"
  44
  45 #define SHIFT 1
  46 #include "softmmu_template.h"
  47
  48 #define SHIFT 2
  49 #include "softmmu_template.h"
  50
  51 #define SHIFT 3
  52 #include "softmmu_template.h"
  53
  54 /* Try to fill the TLB and return an exception if error. If retaddr is
  55    NULL, it means that the function was called in C code (i.e. not
  56    from generated code or from helper.c) */
  57 /* XXX: fix it to restore all registers */
  58 void tlb_fill(CPUM68KState *env1, target_ulong addr, int is_write, int mmu_idx,
  59               void *retaddr)
  60 {
  61     TranslationBlock *tb;
  62     CPUM68KState *saved_env;
  63     unsigned long pc;
  64     int ret;
  65
  66     saved_env = env;
  67     env = env1;
  68     ret = cpu_m68k_handle_mmu_fault(env, addr, is_write, mmu_idx);
  69     if (unlikely(ret)) {
  70         if (retaddr) {
  71             /* now we have a real cpu fault */
  72             pc = (unsigned long)retaddr;
  73             tb = tb_find_pc(pc);
  74             if (tb) {
  75                 /* the PC is inside the translated code. It means that we have
  76                    a virtual CPU fault */
  77                 cpu_restore_state(tb, env, pc);
  78             }
  79         }
  80         cpu_loop_exit(env);
  81     }
  82     env = saved_env;
  83 }
  84
  85 static void do_rte(void)
  86 {
  87     uint32_t sp;
  88     uint32_t fmt;
  89
  90     sp = env->aregs[7];
  91     fmt = ldl_kernel(sp);
  92     env->pc = ldl_kernel(sp + 4);
  93     sp |= (fmt >> 28) & 3;
  94     env->sr = fmt & 0xffff;
  95     m68k_switch_sp(env);
  96     env->aregs[7] = sp + 8;
  97 }
  98
  99 static void do_interrupt_all(int is_hw)
 100 {
 101     uint32_t sp;
 102     uint32_t fmt;
 103     uint32_t retaddr;
 104     uint32_t vector;
 105
 106     fmt = 0;
 107     retaddr = env->pc;
 108
 109     if (!is_hw) {
 110         switch (env->exception_index) {
 111         case EXCP_RTE:
 112             /* Return from an exception.  */
 113             do_rte();
 114             return;
 115         case EXCP_HALT_INSN:
 116             if (semihosting_enabled
 117                     && (env->sr & SR_S) != 0
 118                     && (env->pc & 3) == 0
 119                     && lduw_code(env->pc - 4) == 0x4e71
 120                     && ldl_code(env->pc) == 0x4e7bf000) {
 121                 env->pc += 4;
 122                 do_m68k_semihosting(env, env->dregs[0]);
 123                 return;
 124             }
 125             env->halted = 1;
 126             env->exception_index = EXCP_HLT;
 127             cpu_loop_exit(env);
 128             return;
 129         }
 130         if (env->exception_index >= EXCP_TRAP0
 131             && env->exception_index <= EXCP_TRAP15) {
 132             /* Move the PC after the trap instruction.  */
 133             retaddr += 2;
 134         }
 135     }
 136
 137     vector = env->exception_index << 2;
 138
 139     sp = env->aregs[7];
 140
 141     fmt |= 0x40000000;
 142     fmt |= (sp & 3) << 28;
 143     fmt |= vector << 16;
 144     fmt |= env->sr;
 145
 146     env->sr |= SR_S;
 147     if (is_hw) {
 148         env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
 149         env->sr &= ~SR_M;
 150     }
 151     m68k_switch_sp(env);
 152
 153     /* ??? This could cause MMU faults.  */
 154     sp &= ~3;
 155     sp -= 4;
 156     stl_kernel(sp, retaddr);
 157     sp -= 4;
 158     stl_kernel(sp, fmt);
 159     env->aregs[7] = sp;
 160     /* Jump to vector.  */
 161     env->pc = ldl_kernel(env->vbr + vector);
 162 }
 163
 164 void do_interrupt(CPUM68KState *env1)
 165 {
 166     CPUM68KState *saved_env;
 167
 168     saved_env = env;
 169     env = env1;
 170     do_interrupt_all(0);
 171     env = saved_env;
 172 }
 173
 174 void do_interrupt_m68k_hardirq(CPUM68KState *env1)
 175 {
 176     CPUM68KState *saved_env;
 177
 178     saved_env = env;
 179     env = env1;
 180     do_interrupt_all(1);
 181     env = saved_env;
 182 }
 183 #endif
 184
 185 static void raise_exception(int tt)
 186 {
 187     env->exception_index = tt;
 188     cpu_loop_exit(env);
 189 }
 190
 191 void HELPER(raise_exception)(uint32_t tt)
 192 {
 193     raise_exception(tt);
 194 }
 195
 196 void HELPER(divu)(CPUM68KState *env, uint32_t word)
 197 {
 198     uint32_t num;
 199     uint32_t den;
 200     uint32_t quot;
 201     uint32_t rem;
 202     uint32_t flags;
 203
 204     num = env->div1;
 205     den = env->div2;
 206     /* ??? This needs to make sure the throwing location is accurate.  */
 207     if (den == 0)
 208         raise_exception(EXCP_DIV0);
 209     quot = num / den;
 210     rem = num % den;
 211     flags = 0;
 212     /* Avoid using a PARAM1 of zero.  This breaks dyngen because it uses
 213        the address of a symbol, and gcc knows symbols can't have address
 214        zero.  */
 215     if (word && quot > 0xffff)
 216         flags |= CCF_V;
 217     if (quot == 0)
 218         flags |= CCF_Z;
 219     else if ((int32_t)quot < 0)
 220         flags |= CCF_N;
 221     env->div1 = quot;
 222     env->div2 = rem;
 223     env->cc_dest = flags;
 224 }
 225
 226 void HELPER(divs)(CPUM68KState *env, uint32_t word)
 227 {
 228     int32_t num;
 229     int32_t den;
 230     int32_t quot;
 231     int32_t rem;
 232     int32_t flags;
 233
 234     num = env->div1;
 235     den = env->div2;
 236     if (den == 0)
 237         raise_exception(EXCP_DIV0);
 238     quot = num / den;
 239     rem = num % den;
 240     flags = 0;
 241     if (word && quot != (int16_t)quot)
 242         flags |= CCF_V;
 243     if (quot == 0)
 244         flags |= CCF_Z;
 245     else if (quot < 0)
 246         flags |= CCF_N;
 247     env->div1 = quot;
 248     env->div2 = rem;
 249     env->cc_dest = flags;
 250 }