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cpu6502.c
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cpu6502.c
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/*
** 6502 assembler output routines for CVBasic
**
** by Oscar Toledo G.
**
** Creation date: Aug/04/2024.
*/
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include "cvbasic.h"
#include "node.h"
static char temp2[MAX_LINE_SIZE];
static char cpu6502_line[MAX_LINE_SIZE];
static char cpu6502_a[MAX_LINE_SIZE];
static char cpu6502_x[MAX_LINE_SIZE];
static char cpu6502_y[MAX_LINE_SIZE];
static int cpu6502_flag_z_valid;
static void cpu6502_emit_line(void);
static int cpu6502_8bit_simple(struct node *);
void cpu6502_emit_line(void)
{
fprintf(output, "%s", cpu6502_line);
}
void cpu6502_dump(void)
{
}
/*
** Emit a 6502 label
*/
void cpu6502_label(char *label)
{
sprintf(cpu6502_line, "%s:\n", label);
cpu6502_emit_line();
cpu6502_a[0] = '\0';
cpu6502_x[0] = '\0';
cpu6502_y[0] = '\0';
cpu6502_flag_z_valid = 0;
}
/*
** Reset accumulator register (technically a null label)
*/
void cpu6502_empty(void)
{
cpu6502_a[0] = '\0';
cpu6502_x[0] = '\0';
cpu6502_y[0] = '\0';
cpu6502_flag_z_valid = 0;
}
/*
** Emit a 6502 instruction with no operand
*/
void cpu6502_noop(char *mnemonic)
{
/*
** The following instructions aren't used in the compiler
** o BRK
** o RTI
** o PHP
** o PLP
** o CLV
** o CLD
** o SED
** o TXS
** o TSX
** o NOP
*/
sprintf(cpu6502_line, "\t%s\n", mnemonic);
cpu6502_emit_line();
if (strcmp(mnemonic, "PHA") == 0 || strcmp(mnemonic, "SEI") == 0 || strcmp(mnemonic, "CLI") == 0 || strcmp(mnemonic, "SEC") == 0 || strcmp(mnemonic, "CLC") == 0) {
/* Nothing to do */
} else if (strcmp(mnemonic, "PLA") == 0) {
cpu6502_a[0] = '\0';
cpu6502_flag_z_valid = 1;
} else if (strcmp(mnemonic, "TAX") == 0) {
strcpy(cpu6502_x, cpu6502_a);
cpu6502_flag_z_valid = 1;
} else if (strcmp(mnemonic, "TAY") == 0) {
strcpy(cpu6502_y, cpu6502_a);
cpu6502_flag_z_valid = 1;
} else if (strcmp(mnemonic, "TXA") == 0) {
strcpy(cpu6502_a, cpu6502_x);
cpu6502_flag_z_valid = 1;
} else if (strcmp(mnemonic, "TYA") == 0) {
strcpy(cpu6502_a, cpu6502_y);
cpu6502_flag_z_valid = 1;
} else if (strcmp(mnemonic, "INX") == 0 || strcmp(mnemonic, "DEX") == 0) {
cpu6502_x[0] = '\0';
cpu6502_flag_z_valid = 0;
} else if (strcmp(mnemonic, "INY") == 0 || strcmp(mnemonic, "DEY") == 0) {
cpu6502_y[0] = '\0';
cpu6502_flag_z_valid = 0;
} else if (strcmp(mnemonic, "RTS") == 0) {
cpu6502_a[0] = '\0';
cpu6502_x[0] = '\0';
cpu6502_y[0] = '\0';
cpu6502_flag_z_valid = 0;
} else {
fprintf(stderr, "cpu6502_noop: not found mnemonic %s\n", mnemonic);
}
}
/*
** Emit a 6502 instruction with a single operand
*/
void cpu6502_1op(char *mnemonic, char *operand)
{
/*
** The following instructions aren't used in the compiler
** o BVC
** o BVS
** o BIT
*/
/*
** Optimize code finding constants in registers, and
** copy into registers using a single byte instruction.
*/
if (strcmp(mnemonic, "LDA") == 0) {
if (strcmp(operand, cpu6502_x) == 0) {
cpu6502_noop("TXA");
return;
}
if (strcmp(operand, cpu6502_y) == 0) {
cpu6502_noop("TYA");
return;
}
}
if (strcmp(mnemonic, "LDX") == 0) {
if (strcmp(operand, cpu6502_a) == 0) {
cpu6502_noop("TAX");
return;
}
}
if (strcmp(mnemonic, "LDY") == 0) {
if (strcmp(operand, cpu6502_a) == 0) {
cpu6502_noop("TAY");
return;
}
}
sprintf(cpu6502_line, "\t%s %s\n", mnemonic, operand);
cpu6502_emit_line();
if (strcmp(mnemonic, "LDA") == 0) {
if (strchr(operand, ',') != NULL)
cpu6502_a[0] = '\0';
else
strcpy(cpu6502_a, operand);
cpu6502_flag_z_valid = 1;
} else if (strcmp(mnemonic, "LDX") == 0) {
if (strchr(operand, ',') != NULL)
cpu6502_x[0] = '\0';
else
strcpy(cpu6502_x, operand);
cpu6502_flag_z_valid = 0;
} else if (strcmp(mnemonic, "LDY") == 0) {
if (strchr(operand, ',') != NULL)
cpu6502_y[0] = '\0';
else
strcpy(cpu6502_y, operand);
cpu6502_flag_z_valid = 0;
} else if (strcmp(mnemonic, "CMP") == 0 || strcmp(mnemonic, "CPX") == 0 || strcmp(mnemonic, "CPY") == 0) {
/* Only flags affected */
cpu6502_flag_z_valid = 0;
} else if (strcmp(mnemonic, "ADC") == 0 || strcmp(mnemonic, "SBC") == 0 || strcmp(mnemonic, "ORA") == 0 || strcmp(mnemonic, "EOR") == 0 || strcmp(mnemonic, "AND") == 0) {
cpu6502_a[0] = '\0';
cpu6502_flag_z_valid = 1;
} else if (strcmp(mnemonic, "ROR") == 0 || strcmp(mnemonic, "ROL") == 0 || strcmp(mnemonic, "ASL") == 0 || strcmp(mnemonic, "LSR") == 0) {
if (strcmp(operand, "A") == 0) {
cpu6502_a[0] = '\0';
cpu6502_flag_z_valid = 1;
} else {
if (cpu6502_a[0] != '#')
cpu6502_a[0] = '\0';
if (cpu6502_x[0] != '#')
cpu6502_x[0] = '\0';
if (cpu6502_y[0] != '#')
cpu6502_y[0] = '\0';
cpu6502_flag_z_valid = 0;
}
} else if (strcmp(mnemonic, "INC") == 0 || strcmp(mnemonic, "DEC") == 0) {
if (cpu6502_a[0] != '#')
cpu6502_a[0] = '\0';
if (cpu6502_x[0] != '#')
cpu6502_x[0] = '\0';
if (cpu6502_y[0] != '#')
cpu6502_y[0] = '\0';
cpu6502_flag_z_valid = 0;
} else if (strcmp(mnemonic, "JSR") == 0 || strcmp(mnemonic, "JMP") == 0) {
cpu6502_a[0] = '\0';
cpu6502_x[0] = '\0';
cpu6502_y[0] = '\0';
cpu6502_flag_z_valid = 0;
} else if (strcmp(mnemonic, "STA") == 0) {
if (strchr(operand, ',') != NULL)
cpu6502_a[0] = '\0';
else
strcpy(cpu6502_a, operand);
} else if (strcmp(mnemonic, "STX") == 0) {
if (strchr(operand, ',') != NULL)
cpu6502_x[0] = '\0';
else
strcpy(cpu6502_x, operand);
} else if (strcmp(mnemonic, "STY") == 0) {
if (strchr(operand, ',') != NULL)
cpu6502_y[0] = '\0';
else
strcpy(cpu6502_y, operand);
} else if (strcmp(mnemonic, "BEQ") == 0 || strcmp(mnemonic, "BEQ.L") == 0
|| strcmp(mnemonic, "BNE") == 0 || strcmp(mnemonic, "BNE.L") == 0
|| strcmp(mnemonic, "BCC") == 0 || strcmp(mnemonic, "BCC.L") == 0
|| strcmp(mnemonic, "BCS") == 0 || strcmp(mnemonic, "BCS.L") == 0
|| strcmp(mnemonic, "BMI") == 0 || strcmp(mnemonic, "BPL") == 0
|| strcmp(mnemonic, "DB") == 0 || strcmp(mnemonic, "DW") == 0) {
/* Do nothing */
} else {
fprintf(stderr, "cpu6502_1op: not found mnemonic %s\n", mnemonic);
}
}
/*
** Label register usage in tree
**
** This should match exactly register usage in cpu6502_node_generate.
*/
void cpu6502_node_label(struct node *node)
{
/* Nothing to do, yet */
}
/*
** Detect operations that only use A.
*/
static int cpu6502_8bit_simple(struct node *node)
{
switch (node->type) {
case N_LOAD8:
case N_NUM8:
case N_INP:
case N_JOY1:
case N_JOY2:
case N_KEY1:
case N_KEY2:
case N_MUSIC:
case N_NTSC:
case N_VDPSTATUS:
return 1;
case N_NEG8:
case N_NOT8:
return cpu6502_8bit_simple(node->left);
case N_LESSEQUAL8: /* 8-bit <= */
case N_GREATER8: /* 8-bit > */
if (node->left->type != N_NUM8 && node->left->type != N_LOAD8)
return 0;
return cpu6502_8bit_simple(node->right);
case N_OR8: /* 8-bit OR */
case N_XOR8: /* 8-bit XOR */
case N_AND8: /* 8-bit AND */
case N_EQUAL8: /* 8-bit = */
case N_NOTEQUAL8: /* 8-bit <> */
case N_LESS8: /* 8-bit < */
case N_GREATEREQUAL8: /* 8-bit >= */
case N_PLUS8: /* 8-bit + */
case N_MINUS8: /* 8-bit - */
case N_MUL8: /* 8-bit * */
case N_DIV8: /* 8-bit / */
if (node->right->type != N_NUM8 && node->right->type != N_LOAD8)
return 0;
return cpu6502_8bit_simple(node->left);
default:
return 0;
}
}
/*
** Generate code for tree
*/
void cpu6502_node_generate(struct node *node, int decision)
{
struct node *explore;
int stack;
int c;
char *p;
switch (node->type) {
case N_USR: /* Assembly language function with result */
if (node->left != NULL)
cpu6502_node_generate(node->left->left, 0);
cpu6502_1op("JSR", node->label->name);
break;
case N_ADDR: /* Get address of variable */
node_get_label(node, 2);
cpu6502_1op("LDA", temp);
strcat(temp, ">>8");
cpu6502_1op("LDY", temp);
break;
case N_NEG8: /* Negate 8-bit value */
cpu6502_node_generate(node->left, 0);
cpu6502_1op("EOR", "#255");
cpu6502_noop("CLC");
cpu6502_1op("ADC", "#1");
break;
case N_NOT8: /* Complement 8-bit value */
cpu6502_node_generate(node->left, 0);
cpu6502_1op("EOR", "#255");
break;
case N_NEG16: /* Negate 16-bit value */
cpu6502_node_generate(node->left, 0);
cpu6502_1op("EOR", "#255");
cpu6502_noop("CLC");
cpu6502_1op("ADC", "#1");
cpu6502_noop("TAX");
cpu6502_noop("TYA");
cpu6502_1op("EOR", "#255");
cpu6502_1op("ADC", "#0");
cpu6502_noop("TAY");
cpu6502_noop("TXA");
break;
case N_NOT16: /* Complement 16-bit value */
cpu6502_node_generate(node->left, 0);
cpu6502_1op("EOR", "#255");
cpu6502_noop("TAX");
cpu6502_noop("TYA");
cpu6502_1op("EOR", "#255");
cpu6502_noop("TAY");
cpu6502_noop("TXA");
break;
case N_ABS16: /* Get absolute 16-bit value */
cpu6502_node_generate(node->left, 0);
cpu6502_1op("JSR", "_abs16");
break;
case N_SGN16: /* Get sign of 16-bit value */
cpu6502_node_generate(node->left, 0);
cpu6502_1op("JSR", "_sgn16");
break;
case N_POS: /* Get screen cursor position */
cpu6502_1op("LDA", "cursor");
cpu6502_1op("LDY", "cursor+1");
break;
case N_EXTEND8S: /* Extend 8-bit signed value to 16-bit */
cpu6502_node_generate(node->left, 0);
sprintf(temp, INTERNAL_PREFIX "%d", next_local++);
cpu6502_noop("TAX");
cpu6502_1op("AND", "#128");
cpu6502_1op("BPL", temp);
cpu6502_1op("LDA", "#255");
cpu6502_label(temp);
cpu6502_noop("TAY");
cpu6502_noop("TXA");
break;
case N_EXTEND8: /* Extend 8-bit value to 16-bit */
cpu6502_node_generate(node->left, 0);
cpu6502_1op("LDY", "#0");
break;
case N_REDUCE16: /* Reduce 16-bit value to 8-bit */
cpu6502_node_generate(node->left, 0);
break;
case N_READ8: /* Read 8-bit value */
cpu6502_1op("JSR", "_read8");
break;
case N_READ16: /* Read 16-bit value */
cpu6502_1op("JSR", "_read16");
break;
case N_LOAD8: /* Load 8-bit value from address */
strcpy(temp, LABEL_PREFIX);
strcat(temp, node->label->name);
cpu6502_1op("LDA", temp);
break;
case N_LOAD16: /* Load 16-bit value from address */
strcpy(temp, LABEL_PREFIX);
strcat(temp, node->label->name);
cpu6502_1op("LDA", temp);
strcat(temp, "+1");
cpu6502_1op("LDY", temp);
break;
case N_NUM8: /* Load 8-bit constant */
sprintf(temp, "#%d", node->value);
cpu6502_1op("LDA", temp);
break;
case N_NUM16: /* Load 16-bit constant */
sprintf(temp, "#%d", node->value & 0xff);
cpu6502_1op("LDA", temp);
sprintf(temp, "#%d", node->value >> 8);
cpu6502_1op("LDY", temp);
break;
case N_PEEK8: /* Load 8-bit content */
if (node->left->type == N_ADDR) { /* Optimize address */
node_get_label(node->left, 0);
cpu6502_1op("LDA", temp);
break;
}
if ((node->left->type == N_PLUS16 || node->left->type == N_MINUS16)
&& node->left->left->type == N_ADDR
&& node->left->right->type == N_NUM16) { /* Optimize address plus constant */
node_get_label(node->left->left, 0);
p = temp;
while (*p)
p++;
if (node->left->type == N_PLUS16)
*p++ = '+';
else
*p++ = '-';
sprintf(p, "%d", node->left->right->value);
cpu6502_1op("LDA", temp);
break;
}
cpu6502_node_generate(node->left, 0);
cpu6502_1op("JSR", "_peek8");
break;
case N_PEEK16: /* Load 16-bit content */
if (node->left->type == N_ADDR) { /* Optimize address */
node_get_label(node->left, 0);
cpu6502_1op("LDA", temp);
strcat(temp, "+1");
cpu6502_1op("LDY", temp);
break;
}
if ((node->left->type == N_PLUS16 || node->left->type == N_MINUS16)
&& node->left->left->type == N_ADDR
&& node->left->right->type == N_NUM16) { /* Optimize address plus constant */
node_get_label(node->left->left, 0);
p = temp;
while (*p)
p++;
if (node->left->type == N_PLUS16)
*p++ = '+';
else
*p++ = '-';
sprintf(p, "%d", node->left->right->value);
cpu6502_1op("LDA", temp);
strcat(temp, "+1");
cpu6502_1op("LDY", temp);
break;
}
cpu6502_node_generate(node->left, 0);
cpu6502_1op("JSR", "_peek16");
break;
case N_VPEEK: /* Read VRAM */
cpu6502_node_generate(node->left, 0);
cpu6502_noop("SEI");
cpu6502_1op("JSR", "RDVRM");
cpu6502_noop("CLI");
break;
case N_INP: /* Read port */
cpu6502_1op("LDA", "#0"); /* Do nothing */
break;
case N_JOY1: /* Read joystick 1 */
cpu6502_1op("LDA", "joy1_data");
break;
case N_JOY2: /* Read joystick 2 */
cpu6502_1op("LDA", "joy2_data");
break;
case N_KEY1: /* Read keypad 1 */
cpu6502_1op("LDA", "key1_data");
break;
case N_KEY2: /* Read keypad 2 */
cpu6502_1op("LDA", "key2_data");
break;
case N_RANDOM: /* Read pseudorandom generator */
cpu6502_1op("JSR", "random");
break;
case N_FRAME: /* Read current frame number */
cpu6502_1op("LDA", "frame");
cpu6502_1op("LDY", "frame+1");
break;
case N_MUSIC: /* Read music playing status */
cpu6502_1op("LDA", "music_playing");
break;
case N_NTSC: /* Read NTSC flag */
cpu6502_1op("LDA", "ntsc");
break;
case N_VDPSTATUS: /* Read VDP status */
cpu6502_1op("LDA", "vdp_status");
break;
case N_OR8: /* 8-bit OR */
case N_XOR8: /* 8-bit XOR */
case N_AND8: /* 8-bit AND */
case N_EQUAL8: /* 8-bit = */
case N_NOTEQUAL8: /* 8-bit <> */
case N_LESS8: /* 8-bit < */
case N_LESSEQUAL8: /* 8-bit <= */
case N_GREATER8: /* 8-bit > */
case N_GREATEREQUAL8: /* 8-bit >= */
case N_PLUS8: /* 8-bit + */
case N_MINUS8: /* 8-bit - */
case N_MUL8: /* 8-bit * */
case N_DIV8: /* 8-bit / */
if (node->type == N_MUL8 && node->right->type == N_NUM8 && is_power_of_two(node->right->value)) {
cpu6502_node_generate(node->left, 0);
c = node->right->value;
while (c > 1) {
cpu6502_1op("ASL", "A");
c /= 2;
}
break;
}
if (node->type == N_DIV8 && node->right->type == N_NUM8 && is_power_of_two(node->right->value)) {
cpu6502_node_generate(node->left, 0);
c = node->right->value;
while (c > 1) {
cpu6502_1op("LSR", "A");
c /= 2;
}
break;
}
if (node->type == N_LESSEQUAL8 || node->type == N_GREATER8) {
if (node->left->type == N_NUM8) {
cpu6502_node_generate(node->right, 0);
sprintf(temp, "#%d", node->left->value & 0xff);
} else if (node->left->type == N_LOAD8) {
cpu6502_node_generate(node->right, 0);
node_get_label(node->left, 0);
} else {
cpu6502_node_generate(node->right, 0);
cpu6502_noop("PHA");
cpu6502_node_generate(node->left, 0);
cpu6502_1op("STA", "temp");
cpu6502_noop("PLA");
strcpy(temp, "temp");
}
} else if (node->right->type == N_LOAD8) {
cpu6502_node_generate(node->left, 0);
node_get_label(node->right, 0);
} else if (node->right->type == N_NUM8) {
c = node->right->value & 0xff;
cpu6502_node_generate(node->left, 0);
sprintf(temp, "#%d", c);
} else {
cpu6502_node_generate(node->left, 0);
cpu6502_noop("PHA");
cpu6502_node_generate(node->right, 0);
cpu6502_1op("STA", "temp");
cpu6502_noop("PLA");
strcpy(temp, "temp");
}
if (node->type == N_OR8) {
cpu6502_1op("ORA", temp);
if (decision) {
optimized = 1;
sprintf(temp, INTERNAL_PREFIX "%d", decision);
cpu6502_1op("BEQ.L", temp);
}
} else if (node->type == N_XOR8) {
cpu6502_1op("EOR", temp);
if (decision) {
optimized = 1;
sprintf(temp, INTERNAL_PREFIX "%d", decision);
cpu6502_1op("BEQ.L", temp);
}
} else if (node->type == N_AND8) {
cpu6502_1op("AND", temp);
if (decision) {
optimized = 1;
sprintf(temp, INTERNAL_PREFIX "%d", decision);
cpu6502_1op("BEQ.L", temp);
}
} else if (node->type == N_EQUAL8) {
if (strcmp(temp, "#0") != 0 || !cpu6502_flag_z_valid)
cpu6502_1op("CMP", temp);
if (decision) {
optimized = 1;
sprintf(temp, INTERNAL_PREFIX "%d", decision);
cpu6502_1op("BNE.L", temp);
} else {
sprintf(temp, INTERNAL_PREFIX "%d", next_local++);
cpu6502_1op("BEQ", temp);
cpu6502_1op("LDA", "#0");
cpu6502_1op("DB", "$2c"); /* BIT instruction to jump two bytes */
cpu6502_label(temp);
cpu6502_1op("LDA", "#255");
cpu6502_empty();
}
} else if (node->type == N_NOTEQUAL8) {
if (strcmp(temp, "#0") != 0 || !cpu6502_flag_z_valid)
cpu6502_1op("CMP", temp);
if (decision) {
optimized = 1;
sprintf(temp, INTERNAL_PREFIX "%d", decision);
cpu6502_1op("BEQ.L", temp);
} else {
sprintf(temp, INTERNAL_PREFIX "%d", next_local++);
cpu6502_1op("BNE", temp);
cpu6502_1op("LDA", "#0");
cpu6502_1op("DB", "$2c"); /* BIT instruction to jump two bytes */
cpu6502_label(temp);
cpu6502_1op("LDA", "#255");
cpu6502_empty();
}
} else if (node->type == N_LESS8 || node->type == N_GREATER8) {
cpu6502_1op("CMP", temp);
if (decision) {
optimized = 1;
sprintf(temp, INTERNAL_PREFIX "%d", decision);
cpu6502_1op("BCS.L", temp);
} else {
cpu6502_1op("LDA", "#255");
cpu6502_1op("ADC", "#0");
}
} else if (node->type == N_LESSEQUAL8 || node->type == N_GREATEREQUAL8) {
cpu6502_1op("CMP", temp);
if (decision) {
optimized = 1;
sprintf(temp, INTERNAL_PREFIX "%d", decision);
cpu6502_1op("BCC.L", temp);
} else {
cpu6502_1op("LDA", "#255");
cpu6502_1op("ADC", "#0");
cpu6502_1op("EOR", "#255");
}
} else if (node->type == N_PLUS8) {
cpu6502_noop("CLC");
cpu6502_1op("ADC", temp);
} else if (node->type == N_MINUS8) {
cpu6502_noop("SEC");
cpu6502_1op("SBC", temp);
}
break;
case N_ASSIGN8: /* 8-bit assignment */
if ((node->left->type == N_PLUS8 || node->left->type == N_MINUS8 || node->left->type == N_OR8 || node->left->type == N_AND8 || node->left->type == N_XOR8)
&& (node->left->right->type == N_NUM8 || node->left->right->type == N_LOAD8)
&& node_same_address(node->left->left, node->right)) {
if (node->right->type == N_ADDR) {
node_get_label(node->right, 0);
strcpy(temp2, temp);
c = 0;
} else if (((node->right->type == N_PLUS16 || node->right->type == N_MINUS16) && node->right->left->type == N_ADDR && node->right->right->type == N_NUM16)) {
node_get_label(node->right->left, 0);
p = temp;
while (*p)
p++;
if (node->right->type == N_PLUS16)
*p++ = '+';
else
*p++ = '-';
sprintf(p, "%d", node->right->right->value);
strcpy(temp2, temp);
c = 0;
} else {
if (node->right->type == N_PLUS16 && node->right->left->type == N_ADDR && node->right->right->type == N_EXTEND8 && node->right->right->left->type == N_LOAD8) {
node_get_label(node->right->right->left, 0);
strcpy(temp2, temp);
node_get_label(node->right->left, 2);
cpu6502_1op("LDA", temp);
cpu6502_noop("CLC");
cpu6502_1op("ADC", temp2);
cpu6502_1op("STA", "temp");
strcat(temp, ">>8");
cpu6502_1op("LDA", temp);
cpu6502_1op("ADC", "#0");
cpu6502_1op("STA", "temp+1");
} else {
cpu6502_node_generate(node->right, 0);
cpu6502_1op("STA", "temp");
cpu6502_1op("STY", "temp+1");
}
c = 1;
cpu6502_1op("LDY", "#0");
strcpy(temp2, "(temp),Y");
}
if (c == 0 && (node->left->type == N_PLUS8 || node->left->type == N_MINUS8) && node->left->right->type == N_NUM8 && node->left->right->value < 4) {
c = node->left->right->value;
do {
if (node->left->type == N_PLUS8)
cpu6502_1op("INC", temp2);
else
cpu6502_1op("DEC", temp2);
} while (--c) ;
} else {
cpu6502_1op("LDA", temp2);
if (node->left->right->type == N_NUM8)
sprintf(temp, "#%d", node->left->right->value);
else if (node->left->right->type == N_LOAD8)
node_get_label(node->left->right, 0);
if (node->left->type == N_PLUS8) {
cpu6502_noop("CLC");
cpu6502_1op("ADC", temp);
} else if (node->left->type == N_MINUS8) {
cpu6502_noop("SEC");
cpu6502_1op("SBC", temp);
} else if (node->left->type == N_OR8) {
cpu6502_1op("ORA", temp);
} else if (node->left->type == N_AND8) {
cpu6502_1op("AND", temp);
} else if (node->left->type == N_XOR8) {
cpu6502_1op("EOR", temp);
}
cpu6502_1op("STA", temp2);
}
break;
}
if (node->right->type == N_ADDR
|| ((node->right->type == N_PLUS16 || node->right->type == N_MINUS16) && node->right->left->type == N_ADDR && node->right->right->type == N_NUM16)) {
cpu6502_node_generate(node->left, 0);
if (node->right->type == N_ADDR) {
node_get_label(node->right, 0);
} else {
node_get_label(node->right->left, 0);
p = temp;
while (*p)
p++;
if (node->right->type == N_PLUS16)
*p++ = '+';
else
*p++ = '-';
sprintf(p, "%d", node->right->right->value);
}
cpu6502_1op("STA", temp);
break;
}
if (cpu6502_8bit_simple(node->left)) {
cpu6502_node_generate(node->right, 0);
cpu6502_1op("STA", "temp");
cpu6502_1op("STY", "temp+1");
cpu6502_node_generate(node->left, 0);
cpu6502_1op("LDY", "#0");
cpu6502_1op("STA", "(temp),Y");
} else {
cpu6502_node_generate(node->left, 0);
cpu6502_noop("PHA");
cpu6502_node_generate(node->right, 0);
cpu6502_1op("STA", "temp");
cpu6502_1op("STY", "temp+1");
cpu6502_noop("PLA");
cpu6502_1op("LDY", "#0");
cpu6502_1op("STA", "(temp),Y");
}
break;
case N_ASSIGN16: /* 16-bit assignment */
if (node->right->type == N_ADDR) {
c = 1;
} else if (((node->right->type == N_PLUS16 || node->right->type == N_MINUS16) && node->right->left->type == N_ADDR && node->right->right->type == N_NUM16)) {
c = 1;
} else {
c = 0;
}
if (node->left->type == N_PLUS16
&& node->left->right->type == N_NUM16
&& ((c && node->left->right->value == 1) || !c)
&& node_same_address(node->left->left, node->right)) {
if (node->right->type == N_ADDR) {
node_get_label(node->right, 0);
c = 0;
} else if (((node->right->type == N_PLUS16 || node->right->type == N_MINUS16) && node->right->left->type == N_ADDR && node->right->right->type == N_NUM16)) {
node_get_label(node->right->left, 0);
p = temp;
while (*p)
p++;
if (node->right->type == N_PLUS16)
*p++ = '+';
else
*p++ = '-';
sprintf(p, "%d", node->right->right->value);
c = 0;
} else {
cpu6502_node_generate(node->right, 0);
cpu6502_1op("STA", "temp");
cpu6502_1op("STY", "temp+1");
cpu6502_1op("LDY", "#0");
sprintf(temp, "#%d", node->left->right->value & 0xff);
sprintf(temp2, "#%d", node->left->right->value >> 8);
c = 1;
}
if (c == 1) {
cpu6502_noop("CLC");
cpu6502_1op("LDA", "(temp),Y");
cpu6502_1op("ADC", temp);
cpu6502_1op("STA", "(temp),Y");
cpu6502_noop("INY");
cpu6502_1op("LDA", "(temp),Y");
cpu6502_1op("ADC", temp2);
cpu6502_1op("STA", "(temp),Y");
} else {
cpu6502_1op("INC", temp);
sprintf(temp2, INTERNAL_PREFIX "%d", next_local++);
cpu6502_1op("BNE", temp2);
if (c == 1)
cpu6502_noop("INY");
else
strcat(temp, "+1");
cpu6502_1op("INC", temp);
cpu6502_label(temp2);
}
break;
}
if (node->right->type == N_ADDR
|| ((node->right->type == N_PLUS16 || node->right->type == N_MINUS16) && node->right->left->type == N_ADDR && node->right->right->type == N_NUM16)) {
cpu6502_node_generate(node->left, 0);
if (node->right->type == N_ADDR) {
node_get_label(node->right, 0);
} else {
node_get_label(node->right->left, 0);
p = temp;
while (*p)
p++;
if (node->right->type == N_PLUS16)
*p++ = '+';
else
*p++ = '-';
sprintf(p, "%d", node->right->right->value);
}
cpu6502_1op("STA", temp);
strcat(temp, "+1");
cpu6502_1op("STY", temp);
break;
}
if (node->left->type == N_NUM16 || node->left->type == N_LOAD16) {
cpu6502_node_generate(node->right, 0);
cpu6502_1op("STA", "temp");
cpu6502_1op("STY", "temp+1");
cpu6502_node_generate(node->left, 0);
cpu6502_noop("TAX");
cpu6502_noop("TYA");
cpu6502_1op("LDY", "#1");
cpu6502_1op("STA", "(temp),Y");
cpu6502_noop("TXA");
cpu6502_noop("DEY");
cpu6502_1op("STA", "(temp),Y");
} else {
cpu6502_node_generate(node->left, 0);
cpu6502_noop("PHA");
cpu6502_noop("TYA");
cpu6502_noop("PHA");
cpu6502_node_generate(node->right, 0);
cpu6502_1op("STA", "temp");
cpu6502_1op("STY", "temp+1");
cpu6502_noop("PLA");
cpu6502_1op("LDY", "#1");
cpu6502_1op("STA", "(temp),Y");
cpu6502_noop("PLA");
cpu6502_noop("DEY");
cpu6502_1op("STA", "(temp),Y");
}
break;
default: /* Every other node, all remaining are 16-bit operations */
/* Optimization of address plus/minus constant */
if (node->type == N_PLUS16 || node->type == N_MINUS16) {
if (node->left->type == N_ADDR) {
if (node->right->type == N_NUM16) {
node_get_label(node->left, 2);
if (node->type == N_PLUS16)
strcat(temp, "+");
else
strcat(temp, "-");
p = temp;
while (*p)
p++;
sprintf(p, "%d", node->right->value);
cpu6502_1op("LDA", temp);
node_get_label(node->left, 3);
if (node->type == N_PLUS16)
strcat(temp, "+");
else
strcat(temp, "-");
p = temp;
while (*p)
p++;
sprintf(p, "%d)>>8", node->right->value);
cpu6502_1op("LDY", temp);
break;
} else if (node->right->type == N_EXTEND8 && node->right->left->type == N_LOAD8) {
node_get_label(node->left, 2);
cpu6502_1op("LDA", temp);
cpu6502_noop("CLC");
node_get_label(node->right->left, 0);
cpu6502_1op("ADC", temp);
cpu6502_noop("TAX");
node_get_label(node->left, 2);
strcat(temp, ">>8");
cpu6502_1op("LDA", temp);
cpu6502_1op("ADC", "#0");
cpu6502_noop("TAY");
cpu6502_noop("TXA");
break;
}
}
}
if (node->type == N_PLUS16) {
if (node->left->type == N_ADDR) {
cpu6502_node_generate(node->right, 0);
node_get_label(node->left, 2);
cpu6502_noop("CLC");
cpu6502_1op("ADC", temp);
cpu6502_noop("TAX");
cpu6502_noop("TYA");
strcat(temp, ">>8");
cpu6502_1op("ADC", temp);
cpu6502_noop("TAY");
cpu6502_noop("TXA");
break;
}
if (node->left->type == N_NUM16 || node->right->type == N_NUM16) {
if (node->left->type == N_NUM16)
explore = node->left;
else
explore = node->right;
if (node->left != explore)
cpu6502_node_generate(node->left, 0);
else
cpu6502_node_generate(node->right, 0);
c = explore->value;
if ((c & 0xff) == 0 && (c & 0xff00) < 0x0800) {
c = c / 256;
while (c--)
cpu6502_noop("INY");
break;
}
sprintf(temp, "#%d", c & 0xff);
cpu6502_noop("CLC");
if ((c & 0xff) != 0)
cpu6502_1op("ADC", temp);
cpu6502_noop("TAX");
cpu6502_noop("TYA");
sprintf(temp, "#%d", c >> 8);
cpu6502_1op("ADC", temp);
cpu6502_noop("TAY");
cpu6502_noop("TXA");
break;
}
}
if (node->type == N_MINUS16) {
if (node->right->type == N_NUM16)
explore = node->right;
else
explore = NULL;
if (explore != NULL) {
int c = explore->value;
cpu6502_node_generate(node->left, 0);
if ((c & 0xff) == 0 && (c & 0xff00) < 0x0800) {
c = c / 256;
while (c--)
cpu6502_noop("DEY");
break;
}
sprintf(temp, "#%d", c & 0xff);
cpu6502_noop("SEC");
if ((c & 0xff) != 0)
cpu6502_1op("SBC", temp);
cpu6502_noop("TAX");
cpu6502_noop("TYA");
sprintf(temp, "#%d", c >> 8);
cpu6502_1op("SBC", temp);
cpu6502_noop("TAY");
cpu6502_noop("TXA");
break;
}
}
if (node->type == N_OR16 || node->type == N_AND16 || node->type == N_XOR16) {
if (node->right->type == N_NUM16)
explore = node->right;
else
explore = NULL;
if (explore != NULL) {
int value = explore->value;
int byte;
char *mnemonic;
if (node->type == N_OR16) {
mnemonic = "ORA";
} else if (node->type == N_AND16) {
mnemonic = "AND";
} else /*if (node->type == N_XOR16)*/ {
mnemonic = "EOR";
}
if (node->left != explore)
cpu6502_node_generate(node->left, 0);
else
cpu6502_node_generate(node->right, 0);
byte = value & 0xff;
if ((node->type == N_OR16 || node->type == N_XOR16) && byte == 0x00) {
/* Nothing to do :) */
} else if (node->type == N_AND16 && byte == 0xff) {
/* Nothing to do :) */
} else if (node->type == N_AND16 && byte == 0x00) {
cpu6502_1op("LDA", "#0");
} else if (node->type == N_OR16 && byte == 0xff) {
cpu6502_1op("LDA", "#255");
} else {
sprintf(temp, "#%d", byte);
cpu6502_1op(mnemonic, temp);
}
byte = (value >> 8) & 0xff;
if ((node->type == N_OR16 || node->type == N_XOR16) && byte == 0x00) {
/* Nothing to do :) */
} else if (node->type == N_AND16 && byte == 0xff) {
/* Nothing to do :) */
} else if (node->type == N_AND16 && byte == 0x00) {