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(CPUM68KState *env, target_ulong addr, int is_write, int mmu_idx,
  57               uintptr_t retaddr)
  58 {
  59     M68kCPU *cpu = m68k_env_get_cpu(env);
  60     int ret;
  61
  62     ret = m68k_cpu_handle_mmu_fault(CPU(cpu), addr, is_write, mmu_idx);
  63     if (unlikely(ret)) {
  64         if (retaddr) {
  65             /* now we have a real cpu fault */
  66             cpu_restore_state(env, retaddr);
  67         }
  68         cpu_loop_exit(env);
  69     }
  70 }
  71
  72 static void do_rte(CPUM68KState *env)
  73 {
  74     uint32_t sp;
  75     uint32_t fmt;
  76
  77     sp = env->aregs[7];
  78     fmt = cpu_ldl_kernel(env, sp);
  79     env->pc = cpu_ldl_kernel(env, sp + 4);
  80     sp |= (fmt >> 28) & 3;
  81     env->sr = fmt & 0xffff;
  82     m68k_switch_sp(env);
  83     env->aregs[7] = sp + 8;
  84 }
  85
  86 static void do_interrupt_all(CPUM68KState *env, int is_hw)
  87 {
  88     CPUState *cs = CPU(m68k_env_get_cpu(env));
  89     uint32_t sp;
  90     uint32_t fmt;
  91     uint32_t retaddr;
  92     uint32_t vector;
  93
  94     fmt = 0;
  95     retaddr = env->pc;
  96
  97     if (!is_hw) {
  98         switch (cs->exception_index) {
  99         case EXCP_RTE:
 100             /* Return from an exception.  */
 101             do_rte(env);
 102             return;
 103         case EXCP_HALT_INSN:
 104             if (semihosting_enabled
 105                     && (env->sr & SR_S) != 0
 106                     && (env->pc & 3) == 0
 107                     && cpu_lduw_code(env, env->pc - 4) == 0x4e71
 108                     && cpu_ldl_code(env, env->pc) == 0x4e7bf000) {
 109                 env->pc += 4;
 110                 do_m68k_semihosting(env, env->dregs[0]);
 111                 return;
 112             }
 113             cs->halted = 1;
 114             cs->exception_index = EXCP_HLT;
 115             cpu_loop_exit(env);
 116             return;
 117         }
 118         if (cs->exception_index >= EXCP_TRAP0
 119             && cs->exception_index <= EXCP_TRAP15) {
 120             /* Move the PC after the trap instruction.  */
 121             retaddr += 2;
 122         }
 123     }
 124
 125     vector = cs->exception_index << 2;
 126
 127     sp = env->aregs[7];
 128
 129     fmt |= 0x40000000;
 130     fmt |= (sp & 3) << 28;
 131     fmt |= vector << 16;
 132     fmt |= env->sr;
 133
 134     env->sr |= SR_S;
 135     if (is_hw) {
 136         env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
 137         env->sr &= ~SR_M;
 138     }
 139     m68k_switch_sp(env);
 140
 141     /* ??? This could cause MMU faults.  */
 142     sp &= ~3;
 143     sp -= 4;
 144     cpu_stl_kernel(env, sp, retaddr);
 145     sp -= 4;
 146     cpu_stl_kernel(env, sp, fmt);
 147     env->aregs[7] = sp;
 148     /* Jump to vector.  */
 149     env->pc = cpu_ldl_kernel(env, env->vbr + vector);
 150 }
 151
 152 void m68k_cpu_do_interrupt(CPUState *cs)
 153 {
 154     M68kCPU *cpu = M68K_CPU(cs);
 155     CPUM68KState *env = &cpu->env;
 156
 157     do_interrupt_all(env, 0);
 158 }
 159
 160 void do_interrupt_m68k_hardirq(CPUM68KState *env)
 161 {
 162     do_interrupt_all(env, 1);
 163 }
 164 #endif
 165
 166 static void raise_exception(CPUM68KState *env, int tt)
 167 {
 168     CPUState *cs = CPU(m68k_env_get_cpu(env));
 169
 170     cs->exception_index = tt;
 171     cpu_loop_exit(env);
 172 }
 173
 174 void HELPER(raise_exception)(CPUM68KState *env, uint32_t tt)
 175 {
 176     raise_exception(env, tt);
 177 }
 178
 179 void HELPER(divu)(CPUM68KState *env, uint32_t word)
 180 {
 181     uint32_t num;
 182     uint32_t den;
 183     uint32_t quot;
 184     uint32_t rem;
 185     uint32_t flags;
 186
 187     num = env->div1;
 188     den = env->div2;
 189     /* ??? This needs to make sure the throwing location is accurate.  */
 190     if (den == 0) {
 191         raise_exception(env, EXCP_DIV0);
 192     }
 193     quot = num / den;
 194     rem = num % den;
 195     flags = 0;
 196     if (word && quot > 0xffff)
 197         flags |= CCF_V;
 198     if (quot == 0)
 199         flags |= CCF_Z;
 200     else if ((int32_t)quot < 0)
 201         flags |= CCF_N;
 202     env->div1 = quot;
 203     env->div2 = rem;
 204     env->cc_dest = flags;
 205 }
 206
 207 void HELPER(divs)(CPUM68KState *env, uint32_t word)
 208 {
 209     int32_t num;
 210     int32_t den;
 211     int32_t quot;
 212     int32_t rem;
 213     int32_t flags;
 214
 215     num = env->div1;
 216     den = env->div2;
 217     if (den == 0) {
 218         raise_exception(env, EXCP_DIV0);
 219     }
 220     quot = num / den;
 221     rem = num % den;
 222     flags = 0;
 223     if (word && quot != (int16_t)quot)
 224         flags |= CCF_V;
 225     if (quot == 0)
 226         flags |= CCF_Z;
 227     else if (quot < 0)
 228         flags |= CCF_N;
 229     env->div1 = quot;
 230     env->div2 = rem;
 231     env->cc_dest = flags;
 232 }