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 "helper.h"
  21
  22 #if defined(CONFIG_USER_ONLY)
  23
  24 void m68k_cpu_do_interrupt(CPUState *cs)
  25 {
  26     cs->exception_index = -1;
  27 }
  28
  29 void do_interrupt_m68k_hardirq(CPUM68KState *env)
  30 {
  31 }
  32
  33 #else
  34
  35 extern int semihosting_enabled;
  36
  37 #include "exec/softmmu_exec.h"
  38
  39 #define MMUSUFFIX _mmu
  40
  41 #define SHIFT 0
  42 #include "exec/softmmu_template.h"
  43
  44 #define SHIFT 1
  45 #include "exec/softmmu_template.h"
  46
  47 #define SHIFT 2
  48 #include "exec/softmmu_template.h"
  49
  50 #define SHIFT 3
  51 #include "exec/softmmu_template.h"
  52
  53 /* Try to fill the TLB and return an exception if error. If retaddr is
  54    NULL, it means that the function was called in C code (i.e. not
  55    from generated code or from helper.c) */
  56 void tlb_fill(CPUState *cs, target_ulong addr, int is_write, int mmu_idx,
  57               uintptr_t retaddr)
  58 {
  59     int ret;
  60
  61     ret = m68k_cpu_handle_mmu_fault(cs, addr, is_write, mmu_idx);
  62     if (unlikely(ret)) {
  63         if (retaddr) {
  64             /* now we have a real cpu fault */
  65             cpu_restore_state(cs, retaddr);
  66         }
  67         cpu_loop_exit(cs);
  68     }
  69 }
  70
  71 static void do_rte(CPUM68KState *env)
  72 {
  73     uint32_t sp;
  74     uint32_t fmt;
  75
  76     sp = env->aregs[7];
  77     fmt = cpu_ldl_kernel(env, sp);
  78     env->pc = cpu_ldl_kernel(env, sp + 4);
  79     sp |= (fmt >> 28) & 3;
  80     env->sr = fmt & 0xffff;
  81     m68k_switch_sp(env);
  82     env->aregs[7] = sp + 8;
  83 }
  84
  85 static void do_interrupt_all(CPUM68KState *env, int is_hw)
  86 {
  87     CPUState *cs = CPU(m68k_env_get_cpu(env));
  88     uint32_t sp;
  89     uint32_t fmt;
  90     uint32_t retaddr;
  91     uint32_t vector;
  92
  93     fmt = 0;
  94     retaddr = env->pc;
  95
  96     if (!is_hw) {
  97         switch (cs->exception_index) {
  98         case EXCP_RTE:
  99             /* Return from an exception.  */
 100             do_rte(env);
 101             return;
 102         case EXCP_HALT_INSN:
 103             if (semihosting_enabled
 104                     && (env->sr & SR_S) != 0
 105                     && (env->pc & 3) == 0
 106                     && cpu_lduw_code(env, env->pc - 4) == 0x4e71
 107                     && cpu_ldl_code(env, env->pc) == 0x4e7bf000) {
 108                 env->pc += 4;
 109                 do_m68k_semihosting(env, env->dregs[0]);
 110                 return;
 111             }
 112             cs->halted = 1;
 113             cs->exception_index = EXCP_HLT;
 114             cpu_loop_exit(cs);
 115             return;
 116         }
 117         if (cs->exception_index >= EXCP_TRAP0
 118             && cs->exception_index <= EXCP_TRAP15) {
 119             /* Move the PC after the trap instruction.  */
 120             retaddr += 2;
 121         }
 122     }
 123
 124     vector = cs->exception_index << 2;
 125
 126     sp = env->aregs[7];
 127
 128     fmt |= 0x40000000;
 129     fmt |= (sp & 3) << 28;
 130     fmt |= vector << 16;
 131     fmt |= env->sr;
 132
 133     env->sr |= SR_S;
 134     if (is_hw) {
 135         env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
 136         env->sr &= ~SR_M;
 137     }
 138     m68k_switch_sp(env);
 139
 140     /* ??? This could cause MMU faults.  */
 141     sp &= ~3;
 142     sp -= 4;
 143     cpu_stl_kernel(env, sp, retaddr);
 144     sp -= 4;
 145     cpu_stl_kernel(env, sp, fmt);
 146     env->aregs[7] = sp;
 147     /* Jump to vector.  */
 148     env->pc = cpu_ldl_kernel(env, env->vbr + vector);
 149 }
 150
 151 void m68k_cpu_do_interrupt(CPUState *cs)
 152 {
 153     M68kCPU *cpu = M68K_CPU(cs);
 154     CPUM68KState *env = &cpu->env;
 155
 156     do_interrupt_all(env, 0);
 157 }
 158
 159 void do_interrupt_m68k_hardirq(CPUM68KState *env)
 160 {
 161     do_interrupt_all(env, 1);
 162 }
 163 #endif
 164
 165 static void raise_exception(CPUM68KState *env, int tt)
 166 {
 167     CPUState *cs = CPU(m68k_env_get_cpu(env));
 168
 169     cs->exception_index = tt;
 170     cpu_loop_exit(cs);
 171 }
 172
 173 void HELPER(raise_exception)(CPUM68KState *env, uint32_t tt)
 174 {
 175     raise_exception(env, tt);
 176 }
 177
 178 void HELPER(divu)(CPUM68KState *env, uint32_t word)
 179 {
 180     uint32_t num;
 181     uint32_t den;
 182     uint32_t quot;
 183     uint32_t rem;
 184     uint32_t flags;
 185
 186     num = env->div1;
 187     den = env->div2;
 188     /* ??? This needs to make sure the throwing location is accurate.  */
 189     if (den == 0) {
 190         raise_exception(env, EXCP_DIV0);
 191     }
 192     quot = num / den;
 193     rem = num % den;
 194     flags = 0;
 195     if (word && quot > 0xffff)
 196         flags |= CCF_V;
 197     if (quot == 0)
 198         flags |= CCF_Z;
 199     else if ((int32_t)quot < 0)
 200         flags |= CCF_N;
 201     env->div1 = quot;
 202     env->div2 = rem;
 203     env->cc_dest = flags;
 204 }
 205
 206 void HELPER(divs)(CPUM68KState *env, uint32_t word)
 207 {
 208     int32_t num;
 209     int32_t den;
 210     int32_t quot;
 211     int32_t rem;
 212     int32_t flags;
 213
 214     num = env->div1;
 215     den = env->div2;
 216     if (den == 0) {
 217         raise_exception(env, EXCP_DIV0);
 218     }
 219     quot = num / den;
 220     rem = num % den;
 221     flags = 0;
 222     if (word && quot != (int16_t)quot)
 223         flags |= CCF_V;
 224     if (quot == 0)
 225         flags |= CCF_Z;
 226     else if (quot < 0)
 227         flags |= CCF_N;
 228     env->div1 = quot;
 229     env->div2 = rem;
 230     env->cc_dest = flags;
 231 }