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Languguage OS 2
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Languguage OS II Version 10-94 (Knowledge Media)(1994).ISO
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embedded
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ibm
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r3sim.arc
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INSTR2.C
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C/C++ Source or Header
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1989-07-08
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696 lines
/******
Program: 68705R3 simulator
File: INSTR2.C
Notes: This file contiains the code for individual 6805 instructions.
It uses routines in INSTR.C
******/
#include "sim.h"
#ifdef MSC
#include <graph.h>
#endif
#define RW_A -1
#define RW_X -2
#define RW_SP -3
/************************************************************************/
/* Routines to set condition code register bits for numeric op result */
int ccr_c( value)
int value;
{
if (value < 0)
{
value += 256;
pgm_model.ccr |= CC_C;
}
else if (value > 255)
{
value -= 256;
pgm_model.ccr |= CC_C;
}
else
pgm_model.ccr &= ~CC_C;
return( value);
}
int ccr_z( value)
int value;
{
if (value == 0)
pgm_model.ccr |= CC_Z;
else
pgm_model.ccr &= ~CC_Z;
return( value);
}
int ccr_n( value)
int value;
{
if (value & 0x80)
pgm_model.ccr |= CC_N;
else
pgm_model.ccr &= ~CC_N;
return( value);
}
/************************************************************************/
int std_ccr(value)
int value;
/* Set C, Z and N bits in ccr based on value */
/* This is appropriate for SUB, CMP, SBC, CPX etc numeric instructions */
{
value = ccr_c( value);
value = ccr_z( value);
value = ccr_n( value);
}
/************************************************************************/
sub( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
pgm_model.a -= data;
pgm_model.a = std_ccr( pgm_model.a);
append_rw( 0, RW_A, pgm_model.a);
}
cmp( mode)
int mode;
{
int addr, data, result;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
result = pgm_model.a - data;
result = std_ccr( result);
}
sbc( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
pgm_model.a -= data;
if (pgm_model.ccr & CC_C)
pgm_model.a--;
pgm_model.a = std_ccr( pgm_model.a);
append_rw( 0, RW_A, pgm_model.a);
}
cpx( mode)
int mode;
{
int addr, data, result;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
result = pgm_model.x - data;
result = std_ccr( result);
}
and( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
pgm_model.a &= data;
pgm_model.a = ccr_n( pgm_model.a);
pgm_model.a = ccr_z( pgm_model.a);
append_rw( 0, RW_A, pgm_model.a);
}
bit( mode)
int mode;
{
int addr, data, result;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
result = pgm_model.a & data;
result = ccr_n( result);
result = ccr_z( result);
}
lda( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
pgm_model.a = data;
pgm_model.a = ccr_n( pgm_model.a);
pgm_model.a = ccr_z( pgm_model.a);
append_rw( 0, RW_A, pgm_model.a);
}
sta( mode)
int mode;
/* Note: mode is never IMMEDIATE */
{
int addr, data, temp;
addr = get_ea( mode);
sim_write( addr, pgm_model.a);
append_rw( 0, addr, pgm_model.a); /* 1 = Read, 0 = Write */
temp = ccr_n( pgm_model.a);
temp = ccr_z( pgm_model.a);
}
eor( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
pgm_model.a ^= data;
pgm_model.a = ccr_n( pgm_model.a);
pgm_model.a = ccr_z( pgm_model.a);
append_rw( 0, RW_A, pgm_model.a);
}
adc( mode)
int mode;
{
int addr, data, result;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
result = pgm_model.a + data;
if (pgm_model.ccr & CC_C)
result++;
if ( ((pgm_model.a & 0x08) & (data & 0x08)) ||
((data & 0x08) & (~result & 0x08)) ||
((pgm_model.a & 0x08) & (~result & 0x08)) )
pgm_model.ccr |= CC_H;
else
pgm_model.ccr &= ~CC_H;
pgm_model.a = std_ccr( result);
append_rw( 0, RW_A, pgm_model.a);
}
ora( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
pgm_model.a |= data;
pgm_model.a = ccr_n( pgm_model.a);
pgm_model.a = ccr_z( pgm_model.a);
append_rw( 0, RW_A, pgm_model.a);
}
add( mode)
int mode;
{
int addr, data, result;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
result = pgm_model.a + data;
if ( ((pgm_model.a & 0x08) & (data & 0x08)) ||
((data & 0x08) & (~result & 0x08)) ||
((pgm_model.a & 0x08) & (~result & 0x08)) )
pgm_model.ccr |= CC_H;
else
pgm_model.ccr &= ~CC_H;
pgm_model.a = std_ccr( result);
append_rw( 0, RW_A, pgm_model.a);
}
jmp( mode)
int mode;
{
if (!disassemble)
pgm_model.pc = get_ea( mode);
/* condition codes are not affected */
}
jsr( mode)
int mode;
{
int addr;
addr = get_ea( mode);
if (!disassemble)
{
push( pgm_model.pc & 0xFF); /* PCL */
push(((pgm_model.pc & 0xF00) >> 8) | 0xF000); /* PCH */
pgm_model.pc = addr;
}
}
bsr( mode)
int mode; /* Must be REL */
{
jsr( mode); /* identical to JSR except for address mode, */
/* which is handled by get_ea() */
}
ldx( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
pgm_model.x = data;
data = ccr_n( data);
data = ccr_z( data);
}
stx( mode)
{
int addr, data;
addr = get_ea( mode);
sim_write( addr, pgm_model.x);
append_rw( 0, addr, pgm_model.x); /* 1 = Read, 0 = Write */
data = pgm_model.x;
data = ccr_n( data);
data = ccr_z( data);
}
bset( bit)
int bit;
{
int addr, data;
addr = get_ea( DIRECT);
data = sim_bitread( addr, bit); /* Returns byte value just like simread */
/* Bit is used to check bit in ports */
/* See sim_mem.c */
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
data |= 1<<bit;
sim_write( addr, data);
append_rw( 0, addr, data); /* 1 = Read, 0 = Write */
}
bclr( bit)
int bit;
{
int addr, data;
addr = get_ea( DIRECT);
data = sim_bitread( addr, bit); /* See note above */
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
data &= ~(1<<bit);
sim_write( addr, data);
append_rw( 0, addr, data); /* 1 = Read, 0 = Write */
}
brset( bit)
int bit;
{
int addr, data;
addr = get_ea( DIRECT);
data = sim_bitread( addr, bit); /* Returns byte value just like simread */
/* Bit is used to check bit in ports */
/* See sim_mem.c */
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
addr = get_ea( BTB); /* Bit Test & Branch - branch rel */
if (data & (1 << bit))
{
if (!disassemble)
pgm_model.pc = addr;
pgm_model.ccr |= CC_C;
}
else
pgm_model.ccr &= ~CC_C;
}
brclr( bit)
int bit;
{
int addr, data;
addr = get_ea( DIRECT);
data = sim_bitread( addr, bit); /* See note above */
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
addr = get_ea( BTB); /* Bit Test & Branch - branch rel */
if (data & (1 << bit))
pgm_model.ccr |= CC_C;
else
{
if (!disassemble)
pgm_model.pc = addr;
pgm_model.ccr &= ~CC_C;
}
}
branch( brtype)
int brtype;
{
int addr, brflag;
addr = get_ea( REL);
switch (brtype)
{
case 0: /* BRA */
brflag = 1;
break;
case 1: /* BRN */
brflag = 0;
break;
case 2: /* BHI */
brflag= ((pgm_model.ccr & CC_C) == 0) && ((pgm_model.ccr & CC_Z) == 0);
break;
case 3: /* BLS */
brflag= ((pgm_model.ccr & CC_C) != 0) || ((pgm_model.ccr & CC_Z) != 0);
break;
case 4: /* BCC */
brflag = ((pgm_model.ccr & CC_C) == 0);
break;
case 5: /* BCS */
brflag = ((pgm_model.ccr & CC_C) != 0);
break;
case 6: /* BNE */
brflag = ((pgm_model.ccr & CC_Z) == 0);
break;
case 7: /* BEQ */
brflag = ((pgm_model.ccr & CC_Z) != 0);
break;
case 8: /* BHCC */
brflag = ((pgm_model.ccr & CC_H) == 0);
break;
case 9: /* BHCS */
brflag = ((pgm_model.ccr & CC_H) != 0);
break;
case 10: /* BPL */
brflag = ((pgm_model.ccr & CC_N) == 0);
break;
case 11: /* BMI */
brflag = ((pgm_model.ccr & CC_N) != 0);
break;
case 12: /* BMC */
brflag = ((pgm_model.ccr & CC_I) == 0);
break;
case 13: /* BMS */
brflag = ((pgm_model.ccr & CC_I) != 0);
break;
case 14: /* BIL */
brflag = external_intr;
break;
case 15: /* BIH */
brflag = !external_intr;
break;
default:
brflag = 0;
break;
}
if (brflag && !disassemble)
pgm_model.pc = addr;
}
neg( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
data = 0 - data;
data = std_ccr( data); /* will get value in 0-255 and set C, N, Z */
sim_write( addr, data);
append_rw( 0, addr, data); /* 1 = Read, 0 = Write */
}
com( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
data ^= 0xFF;
data = ccr_n( data);
data = ccr_z( data);
pgm_model.ccr |= CC_C; /* Carry always set */
sim_write( addr, data);
append_rw( 0, addr, data); /* 1 = Read, 0 = Write */
}
lsr( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
if (data & 0x01)
pgm_model.ccr |= CC_C;
else
pgm_model.ccr &= ~CC_C;
data >>= 1;
data = ccr_n( data); /* N will always be 0 */
data = ccr_z( data);
sim_write( addr, data);
append_rw( 0, addr, data); /* 1 = Read, 0 = Write */
}
ror( mode)
int mode;
{
int addr, data, newdata;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
newdata = data >>1;
if (pgm_model.ccr & CC_C)
newdata |= 0x80;
if (data & 0x01)
pgm_model.ccr |= CC_C;
else
pgm_model.ccr &= ~CC_C;
newdata = ccr_n( newdata);
newdata = ccr_z( newdata);
sim_write( addr, newdata);
append_rw( 0, addr, newdata); /* 1 = Read, 0 = Write */
}
asr( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
if (data & 0x01)
pgm_model.ccr |= CC_C;
else
pgm_model.ccr &= ~CC_C;
data >>= 1;
if (data & 0x40)
data |= 0x80; /* hold bit 7 constant */
data = ccr_n( data);
data = ccr_z( data);
sim_write( addr, data);
append_rw( 0, addr, data); /* 1 = Read, 0 = Write */
}
lsl( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
data <<= 1;
data = std_ccr( data); /* if b7 was on, C will be set and data */
/* corrected by subtracting 256 - perfect! */
sim_write( addr, data);
append_rw( 0, addr, data); /* 1 = Read, 0 = Write */
}
rol( mode)
int mode;
{
int addr, data, newdata;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
newdata = data <<1;
if (pgm_model.ccr & CC_C)
newdata |= 0x01;
if (data & 0x80)
pgm_model.ccr |= CC_C;
else
pgm_model.ccr &= ~CC_C;
newdata = ccr_n( newdata);
newdata = ccr_z( newdata);
sim_write( addr, newdata);
append_rw( 0, addr, newdata); /* 1 = Read, 0 = Write */
}
dec( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
data -= 1;
if (data < 0)
data = 255;
data = ccr_n( data);
data = ccr_z( data);
sim_write( addr, data);
append_rw( 0, addr, data); /* 1 = Read, 0 = Write */
}
inc( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
data += 1;
if (data >= 256)
data = 0;
data = ccr_n( data);
data = ccr_z( data);
sim_write( addr, data);
append_rw( 0, addr, data); /* 1 = Read, 0 = Write */
}
tst( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
/* No operation on data, or, if you prefer data = data - 0 */
data = ccr_n( data);
data = ccr_z( data);
}
clr( mode)
int mode;
{
int addr, data;
addr = get_ea( mode);
data = sim_read( addr);
append_rw( 1, addr, data); /* 1 = Read, 0 = Write */
data = 0;
data = ccr_n( data);
data = ccr_z( data);
sim_write( addr, data);
append_rw( 0, addr, data); /* 1 = Read, 0 = Write */
}
swi(mode)
int mode;
{
rinterrupt( 0xFFC); /* in instr.c */
}
rts(mode)
int mode;
{
if (!disassemble)
{
pgm_model.pc = (( pull() & 0x0F ) << 8);
pgm_model.pc += pull();
}
}
rti(mode)
int mode;
{
pgm_model.ccr = pull() & 0x1F;
pgm_model.a = pull();
pgm_model.x = pull();
rts( mode);
}
tax( mode)
int mode;
{
pgm_model.x = pgm_model.a;
append_rw( 0, RW_X, pgm_model.x); /* 1 = Read, 0 = Write */
}
txa( mode)
int mode;
{
pgm_model.a = pgm_model.x;
append_rw( 0, RW_A, pgm_model.a); /* 1 = Read, 0 = Write */
}
clc( mode)
int mode;
{
pgm_model.ccr &= ~CC_C;
}
sec( mode)
int mode;
{
pgm_model.ccr |= CC_C;
}
cli( mode)
int mode;
{
pgm_model.ccr &= ~CC_I;
}
sei( mode)
int mode;
{
pgm_model.ccr |= CC_I;
}
nop( mode)
int mode;
{
/* no operation */
return( mode);
}
rsp( mode)
int mode;
{
pgm_model.sp = 0x7F;
}
/**************** end of file instr2.c **********************************/