xmix_vm.c

汇编语言编程源代码

/* ---------------------- xmix_vm.c :
 * Implementation of the functions declared in xmix_vm.h
 * ------------------------------------------------------------------
 * Copyright (C) 2000 Free Software Foundation, Inc.
 *  
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *  
 * This program 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 General Public License for more details.
 *  
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *  
 */



#include "xmix_vm.h"

/* auxiliar functions */
G_INLINE_FUNC mix_address_t
get_M_(const mix_vm_t *vm, const mix_ins_t *ins);
G_INLINE_FUNC mix_word_t
get_V_(const mix_vm_t *vm, const mix_ins_t *ins);
G_INLINE_FUNC mix_device_t *
get_dev_ (mix_vm_t *vm, mix_fspec_t type);

G_INLINE_FUNC mix_address_t
get_M_(const mix_vm_t *vm, const mix_ins_t *ins)
{
  if ( ins->index == 0 )
    return ins->address;
  else
    return mix_short_add(ins->address, 
			 mix_word_to_short_fast(get_rI_(vm, ins->index)));
}

G_INLINE_FUNC mix_word_t
get_V_(const mix_vm_t *vm, const mix_ins_t *ins)
{
  return mix_word_get_field(ins->fspec, get_cell_(vm, get_M_(vm,ins)));
}

G_INLINE_FUNC mix_device_t *
get_dev_ (mix_vm_t *vm, mix_fspec_t type) 
{
  if (type >= BD_NO_) return NULL;
  if (vm->devices[type] == NULL)
    vm->devices[type] = vm->factory (type);
  return vm->devices[type];
}

/* Instruction handlers */

static gboolean 
nop_handler_(mix_vm_t *vm, const mix_ins_t *ins)
{
  g_assert(ins->opcode == mix_opNOP);
  inc_loc_(vm);
  return TRUE;
}

static gboolean 
add_handler_(mix_vm_t *vm, const mix_ins_t *ins)
{
  mix_word_t val = get_V_(vm, ins);
  g_assert(ins->opcode == mix_opADD || ins->opcode == mix_opSUB);
  if ( ins->opcode == mix_opSUB ) mix_word_reverse_sign(val);
  if ( mix_word_add_and_carry(get_rA_(vm), val, NULL, &get_rA_(vm)) )
    set_over_(vm,TRUE);
  inc_loc_(vm);
  return TRUE;
}


static gboolean 
mul_handler_(mix_vm_t *vm, const mix_ins_t *ins)
{
  g_assert(ins->opcode == mix_opMUL);
  mix_word_mul(get_rA_(vm), get_V_(vm,ins), &get_rA_(vm), &get_rX_(vm));
  inc_loc_(vm);
  return TRUE;
}

static gboolean 
div_handler_(mix_vm_t *vm, const mix_ins_t *ins)
{
  g_assert(ins->opcode == mix_opDIV);
  if ( mix_word_div(get_rA_(vm), get_rX_(vm), get_V_(vm,ins),
		    &get_rA_(vm), &get_rX_(vm)) )
    set_over_(vm,TRUE);
  inc_loc_(vm);
  return TRUE;
}

static gboolean 
spc_handler_(mix_vm_t *vm, const mix_ins_t *ins)
{
  g_assert(ins->opcode == mix_opSPC);
  
  switch (mix_ins_id_from_ins(*ins)) {
  case mix_HLT: halt_(vm, TRUE); break;
  case mix_CHAR:
    { 
      guint32 num = mix_word_magnitude(get_rA_(vm));
      mix_char_t z = mix_ascii_to_char('0');
      guint i;
      for (i = 5; 0 < i; --i, num /= 10)
	mix_word_set_byte(&get_rX_(vm), i, z + num % 10);
      for (i = 5; 0 < i; --i, num /= 10)
	mix_word_set_byte(&get_rA_(vm), i, z + num % 10);
      break;
    }
  case mix_NUM: 
    { 
      guint i;
      mix_word_t num = MIX_WORD_ZERO;
      mix_word_t ten = 10;
      for (i = 1; i <= 5; ++i) {
	mix_word_mul(ten, num, NULL, &num);
	mix_word_add_and_carry(num, mix_word_get_byte(get_rA_(vm),i)%10,
			       NULL, &num);
      }
      for (i = 1; i <= 5; ++i) {
	mix_word_mul(ten, num, NULL, &num);
	mix_word_add_and_carry(num, mix_word_get_byte(get_rX_(vm),i)%10,
			       NULL, &num);
      }
      set_rA_(vm,
	      mix_word_is_negative(get_rA_(vm)) ? mix_word_negative(num):num);
      break;
    }
  default: return FALSE;
  }
  inc_loc_(vm);
  return TRUE;
}

static gboolean 
sla_handler_(mix_vm_t *vm, const mix_ins_t *ins)
{
  mix_short_t n = get_M_(vm,ins);
  
  g_assert(ins->opcode == mix_opSLx);
  g_return_val_if_fail(mix_short_is_positive(n), FALSE);
  
  switch ( mix_ins_id_from_ins(*ins) ) {
  case mix_SLA:
    mix_word_shift_left(get_rA_(vm), MIX_WORD_ZERO, n, &get_rA_(vm), NULL);
    break;
  case mix_SRA:
    mix_word_shift_right(get_rA_(vm), MIX_WORD_ZERO, n, &get_rA_(vm), NULL);
    break;
  case mix_SLAX:
    mix_word_shift_left(get_rA_(vm), get_rX_(vm), n, 
			&get_rA_(vm), &get_rX_(vm));
    break;
  case mix_SRAX:
    mix_word_shift_right(get_rA_(vm), get_rX_(vm), n, 
			&get_rA_(vm), &get_rX_(vm));
    break;
  case mix_SLC:
    mix_word_shift_left_circular(get_rA_(vm), get_rX_(vm), n, 
				 &get_rA_(vm), &get_rX_(vm));
    break;
  case mix_SRC:
    mix_word_shift_right_circular(get_rA_(vm), get_rX_(vm), n, 
				  &get_rA_(vm), &get_rX_(vm));
    break;
  default:
    return FALSE;
  }
  
  inc_loc_(vm);
  return TRUE;
}

static gboolean 
mov_handler_(mix_vm_t *vm, const mix_ins_t *ins)
{
  mix_short_t from = get_M_(vm,ins), 
    to = mix_word_to_short_fast(get_rI_(vm,1));
  guint k, delta = ins->fspec;
  
  g_assert(ins->opcode == mix_opMOVE);
  g_return_val_if_fail(mix_short_is_positive(from), FALSE);
  g_return_val_if_fail(mix_short_is_positive(to), FALSE);
  g_return_val_if_fail(MEMOK_(from + delta -1), FALSE);
  g_return_val_if_fail(MEMOK_(to + delta - 1), FALSE);
  
  for (k = 0; k < delta; ++k)
    set_cell_(vm, to+k, get_cell_(vm, from+k));
  set_rI_(vm, 1, to+delta);
  inc_loc_(vm);
  return TRUE;
}

static gboolean
lda_handler_(mix_vm_t *vm, const mix_ins_t *ins)
{
  gint r = 0;
  mix_word_t val;
  mix_ins_id_t id = mix_ins_id_from_ins(*ins);
    
  g_assert(id >= mix_LDA && id <= mix_LDXN);
  
  val = get_V_(vm, ins);
  if ( id > mix_LDX && mix_fspec_left(ins->fspec) == 0) 
    mix_word_reverse_sign(val);
  if ( (id > mix_LDA && id < mix_LDX) || (id > mix_LDAN && id < mix_LDXN) )
    /* Bytes 1-3 of I regs are always null */
    val = mix_word_set_field(mix_fspec_new(1,3),MIX_WORD_ZERO,val);
        
  switch (id) {
  case mix_LDA: case mix_LDAN: r = A_; break;
  case mix_LDX: case mix_LDXN: r = X_; break;
  case mix_LD1: case mix_LD1N: r = I1_; break;
  case mix_LD2: case mix_LD2N: r = I2_; break;
  case mix_LD3: case mix_LD3N: r = I3_; break;
  case mix_LD4: case mix_LD4N: r = I4_; break;
  case mix_LD5: case mix_LD5N: r = I5_; break;
  case mix_LD6: case mix_LD6N: r = I6_; break;
  default: g_assert_not_reached();
  }
  set_reg_(vm, r, val);
  inc_loc_(vm);
  return TRUE;
}


static gboolean
sta_handler_(mix_vm_t *vm, const mix_ins_t *ins)
{
  mix_address_t addr = get_M_(vm, ins);
  mix_ins_id_t id = mix_ins_id_from_ins(*ins);
  mix_word_t from;
  
  g_assert(id >= mix_STA && id <= mix_STZ);
  switch (id) {
  case mix_STA: from = get_rA_(vm); break;
  case mix_STX: from = get_rX_(vm); break;
  case mix_STJ: from = get_rJ_(vm); break;
  case mix_STZ: from = MIX_WORD_ZERO; break;
  default: from = get_rI_(vm, id - mix_ST1 + 1); break;
  }
  set_cell_(vm, addr,
	    mix_word_store_field(ins->fspec, from,  get_cell_(vm, addr)));
  inc_loc_(vm);
  return TRUE;
}

static gboolean 
jbs_handler_ (mix_vm_t *vm, const mix_ins_t *ins)
{
  g_assert (ins->opcode == mix_opJBUS);
  g_return_val_if_fail (ins->fspec < BD_NO_, TRUE);
  g_return_val_if_fail (get_dev_ (vm, ins->fspec) != NULL, TRUE);
  if ( mix_device_busy (get_dev_ (vm, ins->fspec)) ) {
      set_rJ_(vm, get_loc_ (vm));
      set_loc_ (vm, get_M_ (vm, ins));
  } else inc_loc_ (vm);
  return TRUE;
}

static gboolean 
ioc_handler_(mix_vm_t *vm, const mix_ins_t *ins)
{
  mix_address_t addr;
  mix_device_t *dev;
  gboolean result;
  
  g_assert(ins->opcode == mix_opIOC);
  addr = get_M_ (vm, ins);
  g_return_val_if_fail (ins->fspec < BD_NO_, TRUE);
  dev = get_dev_ (vm, ins->fspec);
  g_return_val_if_fail (dev != NULL, TRUE);
  result =
    mix_device_ioc (dev, addr);