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