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(CPUState *env1)
  26 {
  27     env1->exception_index = -1;
  28 }
  29
  30 void do_interrupt_m68k_hardirq(CPUState *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 (target_ulong addr, int is_write, int mmu_idx, void *retaddr)
  59 {
  60     TranslationBlock *tb;
  61     CPUState *saved_env;
  62     unsigned long pc;
  63     int ret;
  64
  65     /* XXX: hack to restore env in all cases, even if not called from
  66        generated code */
  67     saved_env = env;
  68     env = cpu_single_env;
  69     ret = cpu_m68k_handle_mmu_fault(env, addr, is_write, mmu_idx);
  70     if (unlikely(ret)) {
  71         if (retaddr) {
  72             /* now we have a real cpu fault */
  73             pc = (unsigned long)retaddr;
  74             tb = tb_find_pc(pc);
  75             if (tb) {
  76                 /* the PC is inside the translated code. It means that we have
  77                    a virtual CPU fault */
  78                 cpu_restore_state(tb, env, pc);
  79             }
  80         }
  81         cpu_loop_exit(env);
  82     }
  83     env = saved_env;
  84 }
  85
  86 static void do_rte(void)
  87 {
  88     uint32_t sp;
  89     uint32_t fmt;
  90
  91     sp = env->aregs[7];
  92     fmt = ldl_kernel(sp);
  93     env->pc = ldl_kernel(sp + 4);
  94     sp |= (fmt >> 28) & 3;
  95     env->sr = fmt & 0xffff;
  96     m68k_switch_sp(env);
  97     env->aregs[7] = sp + 8;
  98 }
  99
 100 static void do_interrupt_all(int is_hw)
 101 {
 102     uint32_t sp;
 103     uint32_t fmt;
 104     uint32_t retaddr;
 105     uint32_t vector;
 106
 107     fmt = 0;
 108     retaddr = env->pc;
 109
 110     if (!is_hw) {
 111         switch (env->exception_index) {
 112         case EXCP_RTE:
 113             /* Return from an exception.  */
 114             do_rte();
 115             return;
 116         case EXCP_HALT_INSN:
 117             if (semihosting_enabled
 118                     && (env->sr & SR_S) != 0
 119                     && (env->pc & 3) == 0
 120                     && lduw_code(env->pc - 4) == 0x4e71
 121                     && ldl_code(env->pc) == 0x4e7bf000) {
 122                 env->pc += 4;
 123                 do_m68k_semihosting(env, env->dregs[0]);
 124                 return;
 125             }
 126             env->halted = 1;
 127             env->exception_index = EXCP_HLT;
 128             cpu_loop_exit(env);
 129             return;
 130         }
 131         if (env->exception_index >= EXCP_TRAP0
 132             && env->exception_index <= EXCP_TRAP15) {
 133             /* Move the PC after the trap instruction.  */
 134             retaddr += 2;
 135         }
 136     }
 137
 138     vector = env->exception_index << 2;
 139
 140     sp = env->aregs[7];
 141
 142     fmt |= 0x40000000;
 143     fmt |= (sp & 3) << 28;
 144     fmt |= vector << 16;
 145     fmt |= env->sr;
 146
 147     env->sr |= SR_S;
 148     if (is_hw) {
 149         env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
 150         env->sr &= ~SR_M;
 151     }
 152     m68k_switch_sp(env);
 153
 154     /* ??? This could cause MMU faults.  */
 155     sp &= ~3;
 156     sp -= 4;
 157     stl_kernel(sp, retaddr);
 158     sp -= 4;
 159     stl_kernel(sp, fmt);
 160     env->aregs[7] = sp;
 161     /* Jump to vector.  */
 162     env->pc = ldl_kernel(env->vbr + vector);
 163 }
 164
 165 void do_interrupt(CPUState *env1)
 166 {
 167     CPUState *saved_env;
 168
 169     saved_env = env;
 170     env = env1;
 171     do_interrupt_all(0);
 172     env = saved_env;
 173 }
 174
 175 void do_interrupt_m68k_hardirq(CPUState *env1)
 176 {
 177     CPUState *saved_env;
 178
 179     saved_env = env;
 180     env = env1;
 181     do_interrupt_all(1);
 182     env = saved_env;
 183 }
 184 #endif
 185
 186 static void raise_exception(int tt)
 187 {
 188     env->exception_index = tt;
 189     cpu_loop_exit(env);
 190 }
 191
 192 void HELPER(raise_exception)(uint32_t tt)
 193 {
 194     raise_exception(tt);
 195 }
 196
 197 void HELPER(divu)(CPUState *env, uint32_t word)
 198 {
 199     uint32_t num;
 200     uint32_t den;
 201     uint32_t quot;
 202     uint32_t rem;
 203     uint32_t flags;
 204
 205     num = env->div1;
 206     den = env->div2;
 207     /* ??? This needs to make sure the throwing location is accurate.  */
 208     if (den == 0)
 209         raise_exception(EXCP_DIV0);
 210     quot = num / den;
 211     rem = num % den;
 212     flags = 0;
 213     /* Avoid using a PARAM1 of zero.  This breaks dyngen because it uses
 214        the address of a symbol, and gcc knows symbols can't have address
 215        zero.  */
 216     if (word && quot > 0xffff)
 217         flags |= CCF_V;
 218     if (quot == 0)
 219         flags |= CCF_Z;
 220     else if ((int32_t)quot < 0)
 221         flags |= CCF_N;
 222     env->div1 = quot;
 223     env->div2 = rem;
 224     env->cc_dest = flags;
 225 }
 226
 227 void HELPER(divs)(CPUState *env, uint32_t word)
 228 {
 229     int32_t num;
 230     int32_t den;
 231     int32_t quot;
 232     int32_t rem;
 233     int32_t flags;
 234
 235     num = env->div1;
 236     den = env->div2;
 237     if (den == 0)
 238         raise_exception(EXCP_DIV0);
 239     quot = num / den;
 240     rem = num % den;
 241     flags = 0;
 242     if (word && quot != (int16_t)quot)
 243         flags |= CCF_V;
 244     if (quot == 0)
 245         flags |= CCF_Z;
 246     else if (quot < 0)
 247         flags |= CCF_N;
 248     env->div1 = quot;
 249     env->div2 = rem;
 250     env->cc_dest = flags;
 251 }