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 "exec/helper-proto.h"
  21 #include "exec/cpu_ldst.h"
  22 #include "exec/semihost.h"
  23
  24 #if defined(CONFIG_USER_ONLY)
  25
  26 void m68k_cpu_do_interrupt(CPUState *cs)
  27 {
  28     cs->exception_index = -1;
  29 }
  30
  31 static inline void do_interrupt_m68k_hardirq(CPUM68KState *env)
  32 {
  33 }
  34
  35 #else
  36
  37 /* Try to fill the TLB and return an exception if error. If retaddr is
  38    NULL, it means that the function was called in C code (i.e. not
  39    from generated code or from helper.c) */
  40 void tlb_fill(CPUState *cs, target_ulong addr, int is_write, int mmu_idx,
  41               uintptr_t retaddr)
  42 {
  43     int ret;
  44
  45     ret = m68k_cpu_handle_mmu_fault(cs, addr, is_write, mmu_idx);
  46     if (unlikely(ret)) {
  47         if (retaddr) {
  48             /* now we have a real cpu fault */
  49             cpu_restore_state(cs, retaddr);
  50         }
  51         cpu_loop_exit(cs);
  52     }
  53 }
  54
  55 static void do_rte(CPUM68KState *env)
  56 {
  57     uint32_t sp;
  58     uint32_t fmt;
  59
  60     sp = env->aregs[7];
  61     fmt = cpu_ldl_kernel(env, sp);
  62     env->pc = cpu_ldl_kernel(env, sp + 4);
  63     sp |= (fmt >> 28) & 3;
  64     env->sr = fmt & 0xffff;
  65     env->aregs[7] = sp + 8;
  66     m68k_switch_sp(env);
  67 }
  68
  69 static void do_interrupt_all(CPUM68KState *env, int is_hw)
  70 {
  71     CPUState *cs = CPU(m68k_env_get_cpu(env));
  72     uint32_t sp;
  73     uint32_t fmt;
  74     uint32_t retaddr;
  75     uint32_t vector;
  76
  77     fmt = 0;
  78     retaddr = env->pc;
  79
  80     if (!is_hw) {
  81         switch (cs->exception_index) {
  82         case EXCP_RTE:
  83             /* Return from an exception.  */
  84             do_rte(env);
  85             return;
  86         case EXCP_HALT_INSN:
  87             if (semihosting_enabled()
  88                     && (env->sr & SR_S) != 0
  89                     && (env->pc & 3) == 0
  90                     && cpu_lduw_code(env, env->pc - 4) == 0x4e71
  91                     && cpu_ldl_code(env, env->pc) == 0x4e7bf000) {
  92                 env->pc += 4;
  93                 do_m68k_semihosting(env, env->dregs[0]);
  94                 return;
  95             }
  96             cs->halted = 1;
  97             cs->exception_index = EXCP_HLT;
  98             cpu_loop_exit(cs);
  99             return;
 100         }
 101         if (cs->exception_index >= EXCP_TRAP0
 102             && cs->exception_index <= EXCP_TRAP15) {
 103             /* Move the PC after the trap instruction.  */
 104             retaddr += 2;
 105         }
 106     }
 107
 108     vector = cs->exception_index << 2;
 109
 110     fmt |= 0x40000000;
 111     fmt |= vector << 16;
 112     fmt |= env->sr;
 113
 114     env->sr |= SR_S;
 115     if (is_hw) {
 116         env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
 117         env->sr &= ~SR_M;
 118     }
 119     m68k_switch_sp(env);
 120     sp = env->aregs[7];
 121     fmt |= (sp & 3) << 28;
 122
 123     /* ??? This could cause MMU faults.  */
 124     sp &= ~3;
 125     sp -= 4;
 126     cpu_stl_kernel(env, sp, retaddr);
 127     sp -= 4;
 128     cpu_stl_kernel(env, sp, fmt);
 129     env->aregs[7] = sp;
 130     /* Jump to vector.  */
 131     env->pc = cpu_ldl_kernel(env, env->vbr + vector);
 132 }
 133
 134 void m68k_cpu_do_interrupt(CPUState *cs)
 135 {
 136     M68kCPU *cpu = M68K_CPU(cs);
 137     CPUM68KState *env = &cpu->env;
 138
 139     do_interrupt_all(env, 0);
 140 }
 141
 142 static inline void do_interrupt_m68k_hardirq(CPUM68KState *env)
 143 {
 144     do_interrupt_all(env, 1);
 145 }
 146 #endif
 147
 148 bool m68k_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
 149 {
 150     M68kCPU *cpu = M68K_CPU(cs);
 151     CPUM68KState *env = &cpu->env;
 152
 153     if (interrupt_request & CPU_INTERRUPT_HARD
 154         && ((env->sr & SR_I) >> SR_I_SHIFT) < env->pending_level) {
 155         /* Real hardware gets the interrupt vector via an IACK cycle
 156            at this point.  Current emulated hardware doesn't rely on
 157            this, so we provide/save the vector when the interrupt is
 158            first signalled.  */
 159         cs->exception_index = env->pending_vector;
 160         do_interrupt_m68k_hardirq(env);
 161         return true;
 162     }
 163     return false;
 164 }
 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(cs);
 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 }