mii_emu/src/mii_65c02_asm.c

504 lines
11 KiB
C
Raw Normal View History

/*
* mii_65c02_asm.c
*
* Copyright (C) 2023 Michel Pollet <buserror@gmail.com>
*
* SPDX-License-Identifier: MIT
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "mii_65c02.h"
#include "mii_65c02_ops.h"
#include "mii_65c02_asm.h"
static char *
_mii_extract_token(
char *position,
char *dst,
int dst_len)
{
if (!position)
return NULL;
while (*position == ' ' || *position == '\t')
position++;
char *kw = strsep(&position, " \t");
if (kw)
strncpy(dst, kw, dst_len);
return position;
}
static char *
_mii_extract_name(
char *src,
char *dst,
int dst_len)
{
char *end = src;
while (isalnum(*end) || *end == '_')
*dst++ = *end++;
*dst = 0;
return end;
}
static char *
_mii_extract_value_or_name(
mii_cpu_asm_line_t *l,
char *src)
{
static const char * const hex = "0123456789abcdef";
char *end = src;
l->op_value = 0;
if (*end == '<') {
l->op_low = 1;
end++;
} else if (*end == '>') {
l->op_high = 1;
end++;
}
if (*end == '$') {
end++;
while (isxdigit(*end))
l->op_value = (l->op_value << 4) +
(strchr(hex, tolower(*end++)) - hex);
} else if (isdigit(*end)) {
while (isdigit(*end))
l->op_value = (l->op_value << 4) +
(strchr(hex, tolower(*end++)) - hex);
} else {
end = _mii_extract_name(end, l->op_name, sizeof(l->op_name));
l->label_resolved = 0;
}
return end;
}
static int
_mii_resolve_symbol(
mii_cpu_asm_program_t *p,
mii_cpu_asm_line_t *l,
int optional)
{
if (!l->op_name[0] || l->label_resolved)
return 1;
mii_cpu_asm_line_t *l2 = p->sym;
while (l2) {
if (!strcasecmp(l->op_name, l2->label)) {
l->op_value = l2->op_value;
l->label_resolved = 1;
goto found;
}
l2 = l2->sym_next;
}
if (!optional)
printf("%s symbol %s not found\n", __func__, l->op_name);
return 0;
found:
if (l->op_low)
l->op_value &= 0xff;
else if (l->op_high)
l->op_value >>= 8;
return 1;
}
void
mii_cpu_asm_load(
mii_cpu_asm_program_t *p,
const char *prog)
{
const char *current = prog;
int line_count = 0;
do {
const char *lend = strchr(current, '\n');
int len = lend ? (int)(lend - current) : (int)strlen(current);
mii_cpu_asm_line_t *l = calloc(1, sizeof(mii_cpu_asm_line_t) + len + 1);
l->line_index = line_count++;
sprintf(l->line, "%.*s", len, current);
if (p->prog_tail) {
p->prog_tail->next = l;
p->prog_tail = l;
} else {
p->prog = p->prog_tail = l;
}
char *dup = strdup(l->line);
char * comment = strrchr(dup, ';');
if (comment)
*comment = 0;
if (!*dup) {
goto next_line;
}
char * position = dup;
if (position[0] != ' ' && position[0] != '\t') {
char *start = position;
char *kw = strsep(&position, " \t=");
if (kw) {
// strip spaces
char *ke = kw + strlen(kw);
while (ke > start && (ke[-1] <= ' ' || ke[-1] == ':'))
*--ke = 0;
strncpy(l->label, kw, sizeof(l->label)-1);
}
}
position = _mii_extract_token(position, l->mnemonic, sizeof(l->mnemonic));
if (!strcmp(l->mnemonic, ".db") || !strcmp(l->mnemonic, "byte")) {
/* remaining of the line is comma separated hex values OR symbols
* that can be resolved immediately */
char *kw = position;
while (*kw == ' ' || *kw == '\t') kw++;
char *cur = kw;
while ((cur = strsep(&kw, ",")) != NULL) {
while (*cur == ' ' || *cur == '\t') cur++;
char *ke = cur + strlen(cur);
while (ke > cur && (ke[-1] <= ' ' || ke[-1] == ':'))
*--ke = 0;
if (!*cur)
break;
_mii_extract_value_or_name(l, cur);
if (_mii_resolve_symbol(p, l, 0) == 0)
printf("ERROR -- sorry code symbols don't work, just EQUs\n");
else
l->opcodes[l->opcode_count++] = l->op_value;
}
goto next_line;
}
position = _mii_extract_token(position, l->operand, sizeof(l->operand));
if (l->operand[0] == '.' || l->operand[0] == '=') {
// a directive that has been not aligned on the first line, re-adjust
snprintf(l->label, sizeof(l->label), "%s", l->mnemonic);
snprintf(l->mnemonic, sizeof(l->mnemonic), "%s", l->operand);
position = _mii_extract_token(position, l->operand, sizeof(l->operand));
}
if (l->mnemonic[0] == '=' ||
!strcasecmp(l->mnemonic, "equ") ||
!strcasecmp(l->mnemonic, ".equ")) {
l->symbol = 1;
if (p->sym_tail)
p->sym_tail->sym_next = l;
else
p->sym = l;
_mii_extract_value_or_name(l, l->operand);
if (_mii_resolve_symbol(p, l, 0) == 0)
printf("ERROR -- sorry code symbols don't work, just EQUs\n");
}
// printf(">L:%s M:%s O:%s\n", l->label, l->mnemonic, l->operand);
next_line:
free(dup);
current = lend ? lend+1 : NULL;
} while (current);
}
static int
mii_cpu_opcode_has_mode(
const char *mnemonic,
int mode)
{
for (int i = 0; i < 256; i++) {
if (!strncasecmp(mnemonic, mii_cpu_op[i].name, 4)) {
if (mode == mii_cpu_op[i].desc.mode) {
return i;
}
}
}
return -1;
}
static int
_mii_cpu_asm_parse_operand(
mii_cpu_asm_program_t *p,
mii_cpu_asm_line_t *l)
{
l->mode = IMPLIED;
if (!l->operand[0])
return 0;
char sep = 0; // (parenthesis)
char *src = l->operand;
switch (*src) {
case '#':
l->mode = IMM;
src = _mii_extract_value_or_name(l, src + 1);
break;
case '$':
l->mode = ABS;
src = _mii_extract_value_or_name(l, src);
break;
case '(':
l->mode = IND;
sep = ')';
src = _mii_extract_value_or_name(l, src + 1);
break;
default: {
l->mode = ABS;
src = _mii_extract_value_or_name(l, src);
_mii_resolve_symbol(p, l, 1);
} break;
}
while (*src == ' ' || *src == '\t') src++;
switch (*src) {
case ',':
src++;
while (*src == ' ' || *src == '\t') src++;
switch (tolower(*src)) {
case 'x':
l->mode = ABS_X;
if (sep) {
// special case for JMP ($xxxx,x)
if (!strcasecmp(l->mnemonic, "JMP"))
l->mode = IND_AX;
else
l->mode = IND_X;
break;
}
break;
case 'y':
l->mode = ABS_Y;
break;
default:
l->mode = ABS;
break;
}
break;
case ')':
src++;
switch (*src) {
case ',':
src++;
while (*src == ' ' || *src == '\t') src++;
switch (tolower(*src)) {
case 'x':
l->mode = IND_X;
break;
default:
l->mode = IND_Y;
break;
}
break;
default:
l->mode = IND;
break;
}
break;
}
switch (l->mode) {
case ABS: {
if (l->op_value < 0x100) {
int newo = mii_cpu_opcode_has_mode(l->mnemonic, ZP_REL);
if (newo != -1) {
l->mode = ZP_REL;
l->opcodes[0] = mii_cpu_op[newo].desc.op;
l->opcode_count = mii_cpu_op[newo].desc.pc;
}
}
} break;
case ABS_X: {
if (l->op_value < 0x100) {
int newo = mii_cpu_opcode_has_mode(l->mnemonic, ZP_X);
if (newo != -1) {
l->mode = ZP_X;
l->opcodes[0] = mii_cpu_op[newo].desc.op;
l->opcode_count = mii_cpu_op[newo].desc.pc;
}
}
} break;
case ABS_Y: {
if (l->op_value < 0x100) {
int newo = mii_cpu_opcode_has_mode(l->mnemonic, ZP_Y);
if (newo != -1) {
l->mode = ZP_Y;
l->opcodes[0] = mii_cpu_op[newo].desc.op;
l->opcode_count = mii_cpu_op[newo].desc.pc;
}
}
} break;
case IND: if (1) {
if (l->op_value < 0x100) {
// printf("Testing if IND opcode %s can be IND_Z operand %s (%04x)\n",
// l->mnemonic, l->operand, l->op_value);
int newo = mii_cpu_opcode_has_mode(l->mnemonic, IND_Z);
if (newo != -1) {
// printf("YES replace %02x with %02x\n",
// l->opcodes[0], newo);
l->mode = IND_Z;
l->opcodes[0] = mii_cpu_op[newo].desc.op;
l->opcode_count = mii_cpu_op[newo].desc.pc;
}
}
} break;
}
return 0;
}
int
mii_cpu_asm_assemble(
mii_cpu_asm_program_t *p )
{
mii_cpu_asm_line_t *l = p->prog;
int error = 0;
// fix symbols
l = p->sym;
while (l) {
_mii_extract_value_or_name(l, l->operand);
// printf("SYM %s = %04x\n", l->label, l->op_value);
l = l->sym_next;
}
l = p->prog;
while (l) {
if (!l->mnemonic[0] || l->symbol) {
l = l->next;
continue;
}
l->mode = IMPLIED;
_mii_cpu_asm_parse_operand(p, l);
if (!strcasecmp(l->mnemonic, ".org")) {
if (p->verbose)
printf("%s origin set to $%04x\n", __func__, l->op_value);
if (l->mode == ABS) {
if (!p->org)
p->org = l->op_value;
l->addr_set = 1;
l->addr = l->op_value;
}
l = l->next;
continue;
} else if (!strcasecmp(l->mnemonic, ".verbose")) {
p->verbose = 1;
l = l->next;
continue;
} else if (l->mnemonic[0] == '.') {
l = l->next;
continue;
}
int found = -1;
for (int i = 0; i < 256; i++) {
if (!strncasecmp(l->mnemonic, mii_cpu_op[i].name, 4)) {
if (mii_cpu_op[i].desc.branch) {
l->mode = mii_cpu_op[i].desc.mode;
found = i;
break;
} else if (l->mode == mii_cpu_op[i].desc.mode) {
found = i;
break;
}
}
}
if (found == -1) {
printf("ERROR: %d: %s %s %s\n",
l->line_index, l->label, l->mnemonic, l->operand);
printf(" Missing opcode for %s %d\n", l->mnemonic, l->mode);
error = 1;
break;
}
// printf("FOUND %02x for '%s' '%s' '%s' name:'%s'\n",
// found, l->label, l->mnemonic, l->operand, l->op_name);
l->opcodes[0] = mii_cpu_op[found].desc.op;
l->opcode_count = mii_cpu_op[found].desc.pc;
l = l->next;
}
if (error)
return error;
uint16_t pc = p->org;
/*
* We (should) know all instruction size by now, so lets sets
* the addresses for all the lines
*/
l = p->prog;
while (l) {
if (l->addr_set)
pc = l->addr;
else
l->addr = pc;
if (l->mnemonic[0] != '.') {
// this sets the ones we know about, and clears the ones we dont
for (int i = 1; i < l->opcode_count; i++)
l->opcodes[i] = l->op_value >> (8 * (i - 1));
}
pc += l->opcode_count;
l = l->next;
}
/*
* Now resolve all the operand labels
*/
l = p->prog;
while (l) {
if (l->op_name[0] && !l->label_resolved) {
mii_cpu_asm_line_t *l2 = p->prog;
while (l2) {
int32_t value = 0;
if (!strcasecmp(l->op_name, l2->label)) {
value = l2->op_value;
if (!l2->symbol)
value = l2->addr;
else
value = l2->op_value;
l->op_value = value;
l->label_resolved = 1;
if (mii_cpu_op[l->opcodes[0]].desc.branch)
l->op_value = l2->addr - l->addr - 2;
else if (l->op_low)
l->op_value &= 0xff;
else if (l->op_high)
l->op_value >>= 8;
for (int i = 1; i < l->opcode_count; i++)
l->opcodes[i] = l->op_value >> (8 * (i - 1));
break;
}
l2 = l2->next;
}
if (!l->label_resolved) {
printf("ERROR: Missing label %d: %s %s %s\n",
l->line_index, l->label, l->mnemonic, l->operand);
error = 1;
break;
}
}
l = l->next;
}
if (error)
return error;
p->output_len = p->prog_tail->addr + p->prog_tail->opcode_count - p->org;
if (p->verbose)
printf("%s program at $%04x size %d bytes\n", __func__,
p->org, p->output_len);
p->output = calloc(1, p->output_len);
l = p->prog;
while (l) {
for (int i = 0; i < l->opcode_count; i++)
p->output[l->addr - p->org + i] = l->opcodes[i];
l = l->next;
}
return error;
}
int
mii_cpu_asm(
mii_cpu_asm_program_t *p,
const char *prog)
{
mii_cpu_asm_load(p, prog);
return mii_cpu_asm_assemble(p);
}
void
mii_cpu_asm_free(
mii_cpu_asm_program_t *p)
{
mii_cpu_asm_line_t *l = p->prog;
while (l) {
mii_cpu_asm_line_t *next = l->next;
free(l);
l = next;
}
if (p->output)
free(p->output);
memset(p, 0, sizeof(*p));
}