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/**************************************************************************\
* Microchip PIC16C5x Emulator *
* *
* Copyright Tony La Porta *
* Originally written for the MAME project. *
* *
* *
* Addressing architecture is based on the Harvard addressing scheme. *
* *
* Many thanks to those involved in the i8039 Disassembler *
* as this was based on it. *
* *
* *
* *
* A Address to jump to. *
* B Bit address within an 8-bit file register. *
* D Destination select (0 = store result in W (accumulator)) *
* (1 = store result in file register) *
* F Register file address (00-1F). *
* K Literal field, constant data. *
* *
\**************************************************************************/
#include "emu.h"
#include <ctype.h>
static const UINT8 *rombase;
static const UINT8 *rambase;
static offs_t pcbase;
#define READOP16(A) (rombase[(A) - pcbase] | (rombase[(A) + 1 - pcbase] << 8))
#define READARG16(A) (rambase[(A) - pcbase] | (rambase[(A) + 1 - pcbase] << 8))
typedef unsigned char byte;
typedef unsigned short int word;
#define FMT(a,b) a, b
#define PTRS_PER_FORMAT 2
static const char *const regfile[32] = { "Reg$00 (IND)", "Reg$01 (TMR)", "Reg$02 (PCL)", "Reg$03 (ST)", "Reg$04 (FSR)", "Reg$05 (PTA)", "Reg$06 (PTB)", "Reg$07 (PTC)",
"Reg$08", "Reg$09", "Reg$0A", "Reg$0B", "Reg$0C", "Reg$0D", "Reg$0E", "Reg$0F",
"Reg$10", "Reg$11", "Reg$12", "Reg$13", "Reg$14", "Reg$15", "Reg$16", "Reg$17",
"Reg$18", "Reg$19", "Reg$1A", "Reg$1B", "Reg$1C", "Reg$1D", "Reg$1E", "Reg$1F" };
static const char *const dest[2] = { "W", "Reg" };
static const char *const PIC16C5xFormats[] = {
FMT("000000000000", "nop"),
FMT("000000000010", "option"),
FMT("000000000011", "sleep"),
FMT("000000000100", "clrwdt"),
FMT("000000000101", "tris Port A"),
FMT("000000000110", "tris Port B"),
FMT("000000000111", "tris Port C"),
FMT("0000001fffff", "movwf %F"),
FMT("000001000000", "clrw"),
FMT("0000011fffff", "clrf %F"),
FMT("000010dfffff", "subwf %F,%D"),
FMT("000011dfffff", "decf %F,%D"),
FMT("000100dfffff", "iorwf %F,%D"),
FMT("000101dfffff", "andwf %F,%D"),
FMT("000110dfffff", "xorwf %F,%D"),
FMT("000111dfffff", "addwf %F,%D"),
FMT("001000dfffff", "movf %F,%D"),
FMT("001001dfffff", "comf %F,%D"),
FMT("001010dfffff", "incf %F,%D"),
FMT("001011dfffff", "decfsz %F,%D"),
FMT("001100dfffff", "rrf %F,%D"),
FMT("001101dfffff", "rlf %F,%D"),
FMT("001110dfffff", "swapf %F,%D"),
FMT("001111dfffff", "incfsz %F,%D"),
FMT("0100bbbfffff", "bcf %F,%B"),
FMT("0101bbbfffff", "bsf %F,%B"),
FMT("0110bbbfffff", "btfsc %F,%B"),
FMT("0111bbbfffff", "btfss %F,%B"),
FMT("1000kkkkkkkk", "retlw %K"),
FMT("1001aaaaaaaa", "call %A"),
FMT("101aaaaaaaaa", "goto %A"),
FMT("1100kkkkkkkk", "movlw %K"),
FMT("1101kkkkkkkk", "iorlw %K"),
FMT("1110kkkkkkkk", "andlw %K"),
FMT("1111kkkkkkkk", "xorlw %K"),
NULL
};
#define MAX_OPS ((ARRAY_LENGTH(PIC16C5xFormats) - 1) / PTRS_PER_FORMAT)
struct PIC16C5xOpcode {
word mask; /* instruction mask */
word bits; /* constant bits */
word extcode; /* value that gets extension code */
const char *parse; /* how to parse bits */
const char *fmt; /* instruction format */
};
static PIC16C5xOpcode Op[MAX_OPS+1];
static int OpInizialized = 0;
static void InitDasm16C5x(void)
{
const char *p;
const char *const *ops;
word mask, bits;
int bit;
int i;
ops = PIC16C5xFormats; i = 0;
while (*ops)
{
p = *ops;
mask = 0; bits = 0; bit = 11;
while (*p && bit >= 0)
{
switch (*p++)
{
case '1': mask |= 1<<bit; bits |= 1<<bit; bit--; break;
case '0': mask |= 1<<bit; bit--; break;
case ' ': break;
case 'a':
case 'b':
case 'd':
case 'f':
case 'k':
bit --;
break;
default: fatalerror("Invalid instruction encoding '%s %s'\n",
ops[0],ops[1]);
}
}
if (bit != -1 )
{
fatalerror("not enough bits in encoding '%s %s' %d\n",
ops[0],ops[1],bit);
}
while (isspace((UINT8)*p)) p++;
if (*p) Op[i].extcode = *p;
Op[i].bits = bits;
Op[i].mask = mask;
Op[i].fmt = ops[1];
Op[i].parse = ops[0];
ops += PTRS_PER_FORMAT;
i++;
}
OpInizialized = 1;
}
CPU_DISASSEMBLE( pic16c5x )
{
int a, b, d, f, k; /* these can all be filled in by parsing an instruction */
int i;
int op;
int cnt = 1;
int code;
int bit;
//char *buffertmp;
const char *cp; /* character pointer in OpFormats */
UINT32 flags = 0;
rombase = oprom;
rambase = opram;
pcbase = 2*pc;
if (!OpInizialized) InitDasm16C5x();
op = -1; /* no matching opcode */
code = READOP16(2*pc);
for ( i = 0; i < MAX_OPS; i++)
{
if ((code & Op[i].mask) == Op[i].bits)
{
if (op != -1)
{
osd_printf_debug("Error: opcode %04Xh matches %d (%s) and %d (%s)\n",
code,i,Op[i].fmt,op,Op[op].fmt);
}
op = i;
}
}
if (op == -1)
{
sprintf(buffer,"???? dw %04Xh",code);
return cnt;
}
//buffertmp = buffer;
if (Op[op].extcode) /* Actually, theres no double length opcodes */
{
bit = 27;
code <<= 16;
code |= READARG16(2*(pc+cnt));
cnt++;
}
else
{
bit = 11;
}
/* shift out operands */
cp = Op[op].parse;
a = b = d = f = k = 0;
while (bit >= 0)
{
/* osd_printf_debug("{%c/%d}",*cp,bit); */
switch(*cp)
{
case 'a': a <<=1; a |= ((code & (1<<bit)) ? 1 : 0); bit--; break;
case 'b': b <<=1; b |= ((code & (1<<bit)) ? 1 : 0); bit--; break;
case 'd': d <<=1; d |= ((code & (1<<bit)) ? 1 : 0); bit--; break;
case 'f': f <<=1; f |= ((code & (1<<bit)) ? 1 : 0); bit--; break;
case 'k': k <<=1; k |= ((code & (1<<bit)) ? 1 : 0); bit--; break;
case ' ': break;
case '1': case '0': bit--; break;
case '\0': fatalerror("premature end of parse string, opcode %x, bit = %d\n",code,bit);
}
cp++;
}
/* now traverse format string */
cp = Op[op].fmt;
if (!strncmp(cp, "call", 4))
flags = DASMFLAG_STEP_OVER;
else if (!strncmp(cp, "ret", 3))
flags = DASMFLAG_STEP_OUT;
while (*cp)
{
if (*cp == '%')
{
char num[30], *q;
cp++;
switch (*cp++)
{
case 'A': sprintf(num,"$%03X",a); break;
case 'B': sprintf(num,"%d",b); break;
case 'D': sprintf(num,"%s",dest[d]); break;
case 'F': sprintf(num,"%s",regfile[f]); break;
case 'K': sprintf(num,"%02Xh",k); break;
default:
fatalerror("illegal escape character in format '%s'\n",Op[op].fmt);
}
q = num; while (*q) *buffer++ = *q++;
*buffer = '\0';
}
else
{
*buffer++ = *cp++;
*buffer = '\0';
}
}
return cnt | flags | DASMFLAG_SUPPORTED;
}
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