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