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, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #include "exec.h"
  21 #include "helpers.h"
  22
  23 #if defined(CONFIG_USER_ONLY)
  24
  25 void do_interrupt(int is_hw)
  26 {
  27     env->exception_index = -1;
  28 }
  29
  30 #else
  31
  32 extern int semihosting_enabled;
  33
  34 #define MMUSUFFIX _mmu
  35
  36 #define SHIFT 0
  37 #include "softmmu_template.h"
  38
  39 #define SHIFT 1
  40 #include "softmmu_template.h"
  41
  42 #define SHIFT 2
  43 #include "softmmu_template.h"
  44
  45 #define SHIFT 3
  46 #include "softmmu_template.h"
  47
  48 /* Try to fill the TLB and return an exception if error. If retaddr is
  49    NULL, it means that the function was called in C code (i.e. not
  50    from generated code or from helper.c) */
  51 /* XXX: fix it to restore all registers */
  52 void tlb_fill (target_ulong addr, int is_write, int mmu_idx, void *retaddr)
  53 {
  54     TranslationBlock *tb;
  55     CPUState *saved_env;
  56     unsigned long pc;
  57     int ret;
  58
  59     /* XXX: hack to restore env in all cases, even if not called from
  60        generated code */
  61     saved_env = env;
  62     env = cpu_single_env;
  63     ret = cpu_m68k_handle_mmu_fault(env, addr, is_write, mmu_idx, 1);
  64     if (unlikely(ret)) {
  65         if (retaddr) {
  66             /* now we have a real cpu fault */
  67             pc = (unsigned long)retaddr;
  68             tb = tb_find_pc(pc);
  69             if (tb) {
  70                 /* the PC is inside the translated code. It means that we have
  71                    a virtual CPU fault */
  72                 cpu_restore_state(tb, env, pc, NULL);
  73             }
  74         }
  75         cpu_loop_exit();
  76     }
  77     env = saved_env;
  78 }
  79
  80 static void do_rte(void)
  81 {
  82     uint32_t sp;
  83     uint32_t fmt;
  84
  85     sp = env->aregs[7];
  86     fmt = ldl_kernel(sp);
  87     env->pc = ldl_kernel(sp + 4);
  88     sp |= (fmt >> 28) & 3;
  89     env->sr = fmt & 0xffff;
  90     m68k_switch_sp(env);
  91     env->aregs[7] = sp + 8;
  92 }
  93
  94 void do_interrupt(int is_hw)
  95 {
  96     uint32_t sp;
  97     uint32_t fmt;
  98     uint32_t retaddr;
  99     uint32_t vector;
 100
 101     fmt = 0;
 102     retaddr = env->pc;
 103
 104     if (!is_hw) {
 105         switch (env->exception_index) {
 106         case EXCP_RTE:
 107             /* Return from an exception.  */
 108             do_rte();
 109             return;
 110         case EXCP_HALT_INSN:
 111             if (semihosting_enabled
 112                     && (env->sr & SR_S) != 0
 113                     && (env->pc & 3) == 0
 114                     && lduw_code(env->pc - 4) == 0x4e71
 115                     && ldl_code(env->pc) == 0x4e7bf000) {
 116                 env->pc += 4;
 117                 do_m68k_semihosting(env, env->dregs[0]);
 118                 return;
 119             }
 120             env->halted = 1;
 121             env->exception_index = EXCP_HLT;
 122             cpu_loop_exit();
 123             return;
 124         }
 125         if (env->exception_index >= EXCP_TRAP0
 126             && env->exception_index <= EXCP_TRAP15) {
 127             /* Move the PC after the trap instruction.  */
 128             retaddr += 2;
 129         }
 130     }
 131
 132     vector = env->exception_index << 2;
 133
 134     sp = env->aregs[7];
 135
 136     fmt |= 0x40000000;
 137     fmt |= (sp & 3) << 28;
 138     fmt |= vector << 16;
 139     fmt |= env->sr;
 140
 141     env->sr |= SR_S;
 142     if (is_hw) {
 143         env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
 144         env->sr &= ~SR_M;
 145     }
 146     m68k_switch_sp(env);
 147
 148     /* ??? This could cause MMU faults.  */
 149     sp &= ~3;
 150     sp -= 4;
 151     stl_kernel(sp, retaddr);
 152     sp -= 4;
 153     stl_kernel(sp, fmt);
 154     env->aregs[7] = sp;
 155     /* Jump to vector.  */
 156     env->pc = ldl_kernel(env->vbr + vector);
 157 }
 158
 159 #endif
 160
 161 static void raise_exception(int tt)
 162 {
 163     env->exception_index = tt;
 164     cpu_loop_exit();
 165 }
 166
 167 void HELPER(raise_exception)(uint32_t tt)
 168 {
 169     raise_exception(tt);
 170 }
 171
 172 void HELPER(divu)(CPUState *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(EXCP_DIV0);
 185     quot = num / den;
 186     rem = num % den;
 187     flags = 0;
 188     /* Avoid using a PARAM1 of zero.  This breaks dyngen because it uses
 189        the address of a symbol, and gcc knows symbols can't have address
 190        zero.  */
 191     if (word && quot > 0xffff)
 192         flags |= CCF_V;
 193     if (quot == 0)
 194         flags |= CCF_Z;
 195     else if ((int32_t)quot < 0)
 196         flags |= CCF_N;
 197     env->div1 = quot;
 198     env->div2 = rem;
 199     env->cc_dest = flags;
 200 }
 201
 202 void HELPER(divs)(CPUState *env, uint32_t word)
 203 {
 204     int32_t num;
 205     int32_t den;
 206     int32_t quot;
 207     int32_t rem;
 208     int32_t flags;
 209
 210     num = env->div1;
 211     den = env->div2;
 212     if (den == 0)
 213         raise_exception(EXCP_DIV0);
 214     quot = num / den;
 215     rem = num % den;
 216     flags = 0;
 217     if (word && quot != (int16_t)quot)
 218         flags |= CCF_V;
 219     if (quot == 0)
 220         flags |= CCF_Z;
 221     else if (quot < 0)
 222         flags |= CCF_N;
 223     env->div1 = quot;
 224     env->div2 = rem;
 225     env->cc_dest = flags;
 226 }
 227