text: /*
   *  M68K helper routines
   *
   *  Copyright (c) 2007 CodeSourcery
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, see <http://www.gnu.org/licenses/>.
   */
  #include "cpu.h"
  #include "helper.h"
  
  #if defined(CONFIG_USER_ONLY)
  
  void m68k_cpu_do_interrupt(CPUState *cs)
  {
      cs->exception_index = -1;
  }
  
  void do_interrupt_m68k_hardirq(CPUM68KState *env)
  {
  }
  
  #else
  
  extern int semihosting_enabled;
  
  #include "exec/softmmu_exec.h"
  
  #define MMUSUFFIX _mmu
  
  #define SHIFT 0
  #include "exec/softmmu_template.h"
  
  #define SHIFT 1
  #include "exec/softmmu_template.h"
  
  #define SHIFT 2
  #include "exec/softmmu_template.h"
  
  #define SHIFT 3
  #include "exec/softmmu_template.h"
  
  /* Try to fill the TLB and return an exception if error. If retaddr is
     NULL, it means that the function was called in C code (i.e. not
     from generated code or from helper.c) */
  void tlb_fill(CPUState *cs, target_ulong addr, int is_write, int mmu_idx,
                uintptr_t retaddr)
  {
      int ret;
  
      ret = m68k_cpu_handle_mmu_fault(cs, addr, is_write, mmu_idx);
      if (unlikely(ret)) {
          if (retaddr) {
              /* now we have a real cpu fault */
              cpu_restore_state(cs, retaddr);
          }
          cpu_loop_exit(cs);
      }
  }
  
  static void do_rte(CPUM68KState *env)
  {
      uint32_t sp;
      uint32_t fmt;
  
      sp = env->aregs[7];
      fmt = cpu_ldl_kernel(env, sp);
      env->pc = cpu_ldl_kernel(env, sp + 4);
      sp |= (fmt >> 28) & 3;
      env->sr = fmt & 0xffff;
      m68k_switch_sp(env);
      env->aregs[7] = sp + 8;
  }
  
  static void do_interrupt_all(CPUM68KState *env, int is_hw)
  {
      CPUState *cs = CPU(m68k_env_get_cpu(env));
      uint32_t sp;
      uint32_t fmt;
      uint32_t retaddr;
      uint32_t vector;
  
      fmt = 0;
      retaddr = env->pc;
  
      if (!is_hw) {
          switch (cs->exception_index) {
          case EXCP_RTE:
              /* Return from an exception.  */
              do_rte(env);
              return;
          case EXCP_HALT_INSN:
              if (semihosting_enabled
                      && (env->sr & SR_S) != 0
                      && (env->pc & 3) == 0
                      && cpu_lduw_code(env, env->pc - 4) == 0x4e71
                      && cpu_ldl_code(env, env->pc) == 0x4e7bf000) {
                  env->pc += 4;
                  do_m68k_semihosting(env, env->dregs[0]);
                  return;
              }
              cs->halted = 1;
              cs->exception_index = EXCP_HLT;
              cpu_loop_exit(cs);
              return;
          }
          if (cs->exception_index >= EXCP_TRAP0
              && cs->exception_index <= EXCP_TRAP15) {
              /* Move the PC after the trap instruction.  */
              retaddr += 2;
          }
      }
  
      vector = cs->exception_index << 2;
  
      sp = env->aregs[7];
  
      fmt |= 0x40000000;
      fmt |= (sp & 3) << 28;
      fmt |= vector << 16;
      fmt |= env->sr;
  
      env->sr |= SR_S;
      if (is_hw) {
          env->sr = (env->sr & ~SR_I) | (env->pending_level << SR_I_SHIFT);
          env->sr &= ~SR_M;
      }
      m68k_switch_sp(env);
  
      /* ??? This could cause MMU faults.  */
      sp &= ~3;
      sp -= 4;
      cpu_stl_kernel(env, sp, retaddr);
      sp -= 4;
      cpu_stl_kernel(env, sp, fmt);
      env->aregs[7] = sp;
      /* Jump to vector.  */
      env->pc = cpu_ldl_kernel(env, env->vbr + vector);
  }
  
  void m68k_cpu_do_interrupt(CPUState *cs)
  {
      M68kCPU *cpu = M68K_CPU(cs);
      CPUM68KState *env = &cpu->env;
  
      do_interrupt_all(env, 0);
  }
  
  void do_interrupt_m68k_hardirq(CPUM68KState *env)
  {
      do_interrupt_all(env, 1);
  }
  #endif
  
  static void raise_exception(CPUM68KState *env, int tt)
  {
      CPUState *cs = CPU(m68k_env_get_cpu(env));
  
      cs->exception_index = tt;
      cpu_loop_exit(cs);
  }
  
  void HELPER(raise_exception)(CPUM68KState *env, uint32_t tt)
  {
      raise_exception(env, tt);
  }
  
  void HELPER(divu)(CPUM68KState *env, uint32_t word)
  {
      uint32_t num;
      uint32_t den;
      uint32_t quot;
      uint32_t rem;
      uint32_t flags;
  
      num = env->div1;
      den = env->div2;
      /* ??? This needs to make sure the throwing location is accurate.  */
      if (den == 0) {
          raise_exception(env, EXCP_DIV0);
      }
      quot = num / den;
      rem = num % den;
      flags = 0;
      if (word && quot > 0xffff)
          flags |= CCF_V;
      if (quot == 0)
          flags |= CCF_Z;
      else if ((int32_t)quot < 0)
          flags |= CCF_N;
      env->div1 = quot;
      env->div2 = rem;
      env->cc_dest = flags;
  }
  
  void HELPER(divs)(CPUM68KState *env, uint32_t word)
  {
      int32_t num;
      int32_t den;
      int32_t quot;
      int32_t rem;
      int32_t flags;
  
      num = env->div1;
      den = env->div2;
      if (den == 0) {
          raise_exception(env, EXCP_DIV0);
      }
      quot = num / den;
      rem = num % den;
      flags = 0;
      if (word && quot != (int16_t)quot)
          flags |= CCF_V;
      if (quot == 0)
          flags |= CCF_Z;
      else if (quot < 0)
          flags |= CCF_N;
      env->div1 = quot;
      env->div2 = rem;
      env->cc_dest = flags;
  }
  