410 lines
15 KiB
C
410 lines
15 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include "debugger.h"
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#include "memory.h"
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#include "z80_cpu.h"
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#include "gb.h"
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typedef struct {
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enum {
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LVALUE_MEMORY,
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LVALUE_REG16,
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LVALUE_REG_H,
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LVALUE_REG_L,
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} kind;
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union {
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unsigned short *register_address;
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unsigned short memory_address;
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};
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} lvalue_t;
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static unsigned short read_lvalue(GB_gameboy_t *gb, lvalue_t lvalue)
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{
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/* Not used until we add support for operators like += */
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switch (lvalue.kind) {
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case LVALUE_MEMORY:
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return read_memory(gb, lvalue.memory_address);
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case LVALUE_REG16:
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return *lvalue.register_address;
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case LVALUE_REG_L:
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return *lvalue.register_address & 0x00FF;
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case LVALUE_REG_H:
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return *lvalue.register_address >> 8;
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}
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}
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static void write_lvalue(GB_gameboy_t *gb, lvalue_t lvalue, unsigned short value)
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{
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switch (lvalue.kind) {
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case LVALUE_MEMORY:
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write_memory(gb, lvalue.memory_address, value);
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return;
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case LVALUE_REG16:
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*lvalue.register_address = value;
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return;
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case LVALUE_REG_L:
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*lvalue.register_address &= 0xFF00;
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*lvalue.register_address |= value & 0xFF;
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return;
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case LVALUE_REG_H:
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*lvalue.register_address &= 0x00FF;
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*lvalue.register_address |= value << 8;
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return;
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}
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}
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static unsigned short add(unsigned short a, unsigned short b) {return a + b;};
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static unsigned short sub(unsigned short a, unsigned short b) {return a - b;};
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static unsigned short mul(unsigned short a, unsigned short b) {return a * b;};
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static unsigned short _div(unsigned short a, unsigned short b) {
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if (b == 0) {
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return 0;
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}
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return a / b;
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};
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static unsigned short mod(unsigned short a, unsigned short b) {
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if (b == 0) {
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return 0;
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}
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return a % b;
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};
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static unsigned short and(unsigned short a, unsigned short b) {return a & b;};
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static unsigned short or(unsigned short a, unsigned short b) {return a | b;};
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static unsigned short xor(unsigned short a, unsigned short b) {return a ^ b;};
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static unsigned short shleft(unsigned short a, unsigned short b) {return a << b;};
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static unsigned short shright(unsigned short a, unsigned short b) {return a >> b;};
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static unsigned short assign(GB_gameboy_t *gb, lvalue_t a, unsigned short b)
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{
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write_lvalue(gb, a, b);
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return read_lvalue(gb, a);
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}
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static struct {
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const char *string;
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char priority;
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unsigned short (*operator)(unsigned short, unsigned short);
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unsigned short (*lvalue_operator)(GB_gameboy_t *, lvalue_t, unsigned short);
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} operators[] =
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{
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// Yes. This is not C-like. But it makes much more sense.
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// Deal with it.
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{"+", 0, add},
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{"-", 0, sub},
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{"|", 0, or},
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{"*", 1, mul},
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{"/", 1, _div},
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{"%", 1, mod},
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{"&", 1, and},
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{"^", 1, xor},
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{"<<", 2, shleft},
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{">>", 2, shright},
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{"=", 2, NULL, assign},
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};
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unsigned short debugger_evaluate(GB_gameboy_t *gb, const char *string, unsigned int length, bool *error);
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static lvalue_t debugger_evaluate_lvalue(GB_gameboy_t *gb, const char *string, unsigned int length, bool *error)
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{
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*error = false;
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// Strip whitespace
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while (length && (string[0] == ' ' || string[0] == '\n' || string[0] == '\r' || string[0] == '\t')) {
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string++;
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length--;
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}
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while (length && (string[length-1] == ' ' || string[length-1] == '\n' || string[length-1] == '\r' || string[length-1] == '\t')) {
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length--;
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}
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if (length == 0)
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{
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gb_log(gb, "Expected expression.\n");
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*error = true;
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return (lvalue_t){0,};
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}
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if (string[0] == '(' && string[length - 1] == ')') {
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// Attempt to strip parentheses
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signed int depth = 0;
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for (int i = 0; i < length; i++) {
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if (string[i] == '(') depth++;
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if (depth == 0) {
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// First and last are not matching
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depth = 1;
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break;
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}
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if (string[i] == ')') depth--;
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}
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if (depth == 0) return debugger_evaluate_lvalue(gb, string + 1, length - 2, error);
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}
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else if (string[0] == '[' && string[length - 1] == ']') {
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// Attempt to strip square parentheses (memory dereference)
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signed int depth = 0;
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for (int i = 0; i < length; i++) {
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if (string[i] == '[') depth++;
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if (depth == 0) {
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// First and last are not matching
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depth = 1;
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break;
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}
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if (string[i] == ']') depth--;
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}
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if (depth == 0) {
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return (lvalue_t){LVALUE_MEMORY, .memory_address = debugger_evaluate(gb, string + 1, length - 2, error)};
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}
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}
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// Registers
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if (string[0] == '$') {
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if (length == 2) {
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switch (string[1]) {
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case 'a': return (lvalue_t){LVALUE_REG_H, .register_address = &gb->registers[GB_REGISTER_AF]};
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case 'f': return (lvalue_t){LVALUE_REG_L, .register_address = &gb->registers[GB_REGISTER_AF]};
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case 'b': return (lvalue_t){LVALUE_REG_H, .register_address = &gb->registers[GB_REGISTER_BC]};
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case 'c': return (lvalue_t){LVALUE_REG_L, .register_address = &gb->registers[GB_REGISTER_BC]};
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case 'd': return (lvalue_t){LVALUE_REG_H, .register_address = &gb->registers[GB_REGISTER_DE]};
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case 'e': return (lvalue_t){LVALUE_REG_L, .register_address = &gb->registers[GB_REGISTER_DE]};
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case 'h': return (lvalue_t){LVALUE_REG_H, .register_address = &gb->registers[GB_REGISTER_HL]};
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case 'l': return (lvalue_t){LVALUE_REG_L, .register_address = &gb->registers[GB_REGISTER_HL]};
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}
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}
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else if (length == 3) {
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switch (string[1]) {
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case 'a': if (string[2] == 'f') return (lvalue_t){LVALUE_REG16, .register_address = &gb->registers[GB_REGISTER_AF]};
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case 'b': if (string[2] == 'c') return (lvalue_t){LVALUE_REG16, .register_address = &gb->registers[GB_REGISTER_BC]};
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case 'd': if (string[2] == 'e') return (lvalue_t){LVALUE_REG16, .register_address = &gb->registers[GB_REGISTER_DE]};
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case 'h': if (string[2] == 'l') return (lvalue_t){LVALUE_REG16, .register_address = &gb->registers[GB_REGISTER_HL]};
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case 's': if (string[2] == 'p') return (lvalue_t){LVALUE_REG16, .register_address = &gb->registers[GB_REGISTER_SP]};
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case 'p': if (string[2] == 'c') return (lvalue_t){LVALUE_REG16, .register_address = &gb->pc};
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}
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}
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gb_log(gb, "Unknown register: %.*s\n", length, string);
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*error = true;
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return (lvalue_t){0,};
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}
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gb_log(gb, "Expression is not an lvalue: %.*s\n", length, string);
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*error = true;
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return (lvalue_t){0,};
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}
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unsigned short debugger_evaluate(GB_gameboy_t *gb, const char *string, unsigned int length, bool *error)
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{
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*error = false;
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// Strip whitespace
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while (length && (string[0] == ' ' || string[0] == '\n' || string[0] == '\r' || string[0] == '\t')) {
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string++;
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length--;
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}
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while (length && (string[length-1] == ' ' || string[length-1] == '\n' || string[length-1] == '\r' || string[length-1] == '\t')) {
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length--;
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}
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if (length == 0)
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{
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gb_log(gb, "Expected expression.\n");
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*error = true;
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return -1;
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}
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if (string[0] == '(' && string[length - 1] == ')') {
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// Attempt to strip parentheses
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signed int depth = 0;
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for (int i = 0; i < length; i++) {
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if (string[i] == '(') depth++;
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if (depth == 0) {
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// First and last are not matching
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depth = 1;
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break;
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}
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if (string[i] == ')') depth--;
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}
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if (depth == 0) return debugger_evaluate(gb, string + 1, length - 2, error);
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}
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else if (string[0] == '[' && string[length - 1] == ']') {
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// Attempt to strip square parentheses (memory dereference)
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signed int depth = 0;
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for (int i = 0; i < length; i++) {
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if (string[i] == '[') depth++;
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if (depth == 0) {
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// First and last are not matching
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depth = 1;
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break;
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}
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if (string[i] == ']') depth--;
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}
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if (depth == 0) return read_memory(gb, debugger_evaluate(gb, string + 1, length - 2, error));
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}
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// Search for lowest priority operator
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signed int depth = 0;
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unsigned int operator_index = -1;
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unsigned int operator_pos = 0;
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for (int i = 0; i < length; i++) {
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if (string[i] == '(') depth++;
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else if (string[i] == ')') depth--;
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else if (string[i] == '[') depth++;
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else if (string[i] == ']') depth--;
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else if (depth == 0) {
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for (int j = 0; j < sizeof(operators) / sizeof(operators[0]); j++) {
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if (strlen(operators[j].string) > length - i) continue; // Operator too big.
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// Priority higher than what we already have.
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if (operator_index != -1 && operators[operator_index].priority > operators[j].priority) continue;
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if (memcmp(string + i, operators[j].string, strlen(operators[j].string)) == 0) {
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// Found an operator!
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operator_pos = i;
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operator_index = j;
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}
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}
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}
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}
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if (operator_index != -1) {
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unsigned int right_start = (unsigned int)(operator_pos + strlen(operators[operator_index].string));
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unsigned short right = debugger_evaluate(gb, string + right_start, length - right_start, error);
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if (*error) return -1;
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if (operators[operator_index].lvalue_operator) {
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lvalue_t left = debugger_evaluate_lvalue(gb, string, operator_pos, error);
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if (*error) return -1;
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return operators[operator_index].lvalue_operator(gb, left, right);
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}
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unsigned short left = debugger_evaluate(gb, string, operator_pos, error);
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if (*error) return -1;
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return operators[operator_index].operator(left, right);
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}
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// Not an expression - must be a register or a literal
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// Registers
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if (string[0] == '$') {
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if (length == 2) {
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switch (string[1]) {
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case 'a': return gb->registers[GB_REGISTER_AF] >> 8;
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case 'f': return gb->registers[GB_REGISTER_AF] & 0xFF;
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case 'b': return gb->registers[GB_REGISTER_BC] >> 8;
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case 'c': return gb->registers[GB_REGISTER_BC] & 0xFF;
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case 'd': return gb->registers[GB_REGISTER_DE] >> 8;
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case 'e': return gb->registers[GB_REGISTER_DE] & 0xFF;
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case 'h': return gb->registers[GB_REGISTER_HL] >> 8;
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case 'l': return gb->registers[GB_REGISTER_HL] & 0xFF;
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}
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}
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else if (length == 3) {
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switch (string[1]) {
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case 'a': if (string[2] == 'f') return gb->registers[GB_REGISTER_AF];
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case 'b': if (string[2] == 'c') return gb->registers[GB_REGISTER_BC];
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case 'd': if (string[2] == 'e') return gb->registers[GB_REGISTER_DE];
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case 'h': if (string[2] == 'l') return gb->registers[GB_REGISTER_HL];
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case 's': if (string[2] == 'p') return gb->registers[GB_REGISTER_SP];
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case 'p': if (string[2] == 'c') return gb->pc;
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}
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}
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gb_log(gb, "Unknown register: %.*s\n", length, string);
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*error = true;
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return -1;
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}
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char *end;
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unsigned short literal = (unsigned short) (strtol(string, &end, 16));
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if (end != string + length) {
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gb_log(gb, "Failed to parse: %.*s\n", length, string);
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*error = true;
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return -1;
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}
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return literal;
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}
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/* The debugger interface is quite primitive. One letter commands with a single parameter maximum.
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Only one breakpoint is allowed at a time. More features will be added later. */
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void debugger_run(GB_gameboy_t *gb)
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{
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char *input = NULL;
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if (gb->debug_next_command && gb->debug_call_depth == 0) {
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gb->debug_stopped = true;
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}
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if (gb->debug_fin_command && gb->debug_call_depth == -1) {
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gb->debug_stopped = true;
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}
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if (gb->debug_stopped) {
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cpu_disassemble(gb, gb->pc, 5);
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}
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next_command:
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if (input) {
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free(input);
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}
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if (gb->pc == gb->breakpoint && !gb->debug_stopped) {
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gb->debug_stopped = true;
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gb_log(gb, "Breakpoint: PC = %04x\n", gb->pc);
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cpu_disassemble(gb, gb->pc, 5);
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}
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if (gb->debug_stopped) {
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gb->debug_next_command = false;
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gb->debug_fin_command = false;
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input = gb->input_callback(gb);
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switch (*input) {
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case 'c':
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gb->debug_stopped = false;
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break;
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case 'n':
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gb->debug_stopped = false;
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gb->debug_next_command = true;
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gb->debug_call_depth = 0;
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break;
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case 'f':
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gb->debug_stopped = false;
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gb->debug_fin_command = true;
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gb->debug_call_depth = 0;
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break;
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case 's':
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break;
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case 'r':
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gb_log(gb, "AF = %04x\n", gb->registers[GB_REGISTER_AF]);
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gb_log(gb, "BC = %04x\n", gb->registers[GB_REGISTER_BC]);
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gb_log(gb, "DE = %04x\n", gb->registers[GB_REGISTER_DE]);
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gb_log(gb, "HL = %04x\n", gb->registers[GB_REGISTER_HL]);
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gb_log(gb, "SP = %04x\n", gb->registers[GB_REGISTER_SP]);
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gb_log(gb, "PC = %04x\n", gb->pc);
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gb_log(gb, "TIMA = %d/%lu\n", gb->io_registers[GB_IO_TIMA], gb->tima_cycles);
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gb_log(gb, "Display Controller: LY = %d/%lu\n", gb->io_registers[GB_IO_LY], gb->display_cycles % 456);
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goto next_command;
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case 'x':
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{
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bool error;
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unsigned short addr = debugger_evaluate(gb, input + 1, (unsigned int)strlen(input + 1), &error);
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if (!error) {
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gb_log(gb, "%4x: ", addr);
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for (int i = 0; i < 16; i++) {
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gb_log(gb, "%02x ", read_memory(gb, addr + i));
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}
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gb_log(gb, "\n");
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}
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goto next_command;
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}
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case 'b':
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{
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bool error;
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unsigned short result = debugger_evaluate(gb, input + 1, (unsigned int)strlen(input + 1), &error);
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if (!error) {
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gb_log(gb, "Breakpoint moved to %04x\n", gb->breakpoint = result);
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}
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goto next_command;
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}
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case 'p':
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{
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bool error;
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unsigned short result = debugger_evaluate(gb, input + 1, (unsigned int)strlen(input + 1), &error);
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if (!error) {
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gb_log(gb, "=%04x\n", result);
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}
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goto next_command;
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}
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default:
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goto next_command;
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}
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free(input);
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}
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} |