view debug.c @ 2024:ba5d206dcfea tip

Add ROM DB entry for bootleg game Rock World
author Michael Pavone <pavone@retrodev.com>
date Thu, 03 Dec 2020 00:30:16 -0800
parents 3a46ff899fa6
children a7b753e260a2
line wrap: on
line source
#include "debug.h"
#include "genesis.h"
#include "68kinst.h"
#include <stdlib.h>
#include <string.h>
#ifndef _WIN32
#include <sys/select.h>
#endif
#include "render.h"
#include "util.h"
#include "terminal.h"
#include "z80inst.h"

#ifdef NEW_CORE
#define Z80_OPTS opts
#else
#define Z80_OPTS options
#endif

static bp_def * breakpoints = NULL;
static bp_def * zbreakpoints = NULL;
static uint32_t bp_index = 0;
static uint32_t zbp_index = 0;

bp_def ** find_breakpoint(bp_def ** cur, uint32_t address)
{
	while (*cur) {
		if ((*cur)->address == address) {
			break;
		}
		cur = &((*cur)->next);
	}
	return cur;
}

bp_def ** find_breakpoint_idx(bp_def ** cur, uint32_t index)
{
	while (*cur) {
		if ((*cur)->index == index) {
			break;
		}
		cur = &((*cur)->next);
	}
	return cur;
}

disp_def * displays = NULL;
disp_def * zdisplays = NULL;
uint32_t disp_index = 0;
uint32_t zdisp_index = 0;

void add_display(disp_def ** head, uint32_t *index, char format_char, char * param)
{
	disp_def * ndisp = malloc(sizeof(*ndisp));
	ndisp->format_char = format_char;
	ndisp->param = strdup(param);
	ndisp->next = *head;
	ndisp->index = *index++;
	*head = ndisp;
}

void remove_display(disp_def ** head, uint32_t index)
{
	while (*head) {
		if ((*head)->index == index) {
			disp_def * del_disp = *head;
			*head = del_disp->next;
			free(del_disp->param);
			free(del_disp);
		} else {
			head = &(*head)->next;
		}
	}
}

char * find_param(char * buf)
{
	for (; *buf; buf++) {
		if (*buf == ' ') {
			if (*(buf+1)) {
				return buf+1;
			}
		}
	}
	return NULL;
}

void strip_nl(char * buf)
{
	for(; *buf; buf++) {
		if (*buf == '\n') {
			*buf = 0;
			return;
		}
	}
}

static uint8_t m68k_read_byte(uint32_t address, m68k_context *context)
{
	//TODO: share this implementation with GDB debugger
	return read_byte(address, (void **)context->mem_pointers, &context->options->gen, context);
}

uint16_t m68k_read_word(uint32_t address, m68k_context *context)
{
	return read_word(address, (void **)context->mem_pointers, &context->options->gen, context);
}

uint32_t m68k_read_long(uint32_t address, m68k_context *context)
{
	return m68k_read_word(address, context) << 16 | m68k_read_word(address + 2, context);
}

void debugger_print(m68k_context *context, char format_char, char *param, uint32_t address)
{
	uint32_t value;
	char format[8];
	strcpy(format, "%s: %d\n");
	switch (format_char)
	{
	case 'x':
	case 'X':
	case 'd':
	case 'c':
		format[5] = format_char;
		break;
	case '\0':
		break;
	default:
		fprintf(stderr, "Unrecognized format character: %c\n", format_char);
	}
	if (param[0] == 'd' && param[1] >= '0' && param[1] <= '7') {
		value = context->dregs[param[1]-'0'];
		if (param[2] == '.') {
			if (param[3] == 'w') {
				value &= 0xFFFF;
			} else if (param[3] == 'b') {
				value &= 0xFF;
			}
		}
	} else if (param[0] == 'a' && param[1] >= '0' && param[1] <= '7') {
		value = context->aregs[param[1]-'0'];
		if (param[2] == '.') {
			if (param[3] == 'w') {
				value &= 0xFFFF;
			} else if (param[3] == 'b') {
				value &= 0xFF;
			}
		}
	} else if (param[0] == 's' && param[1] == 'r') {
		value = (context->status << 8);
		for (int flag = 0; flag < 5; flag++) {
			value |= context->flags[flag] << (4-flag);
		}
	} else if(param[0] == 'c') {
		value = context->current_cycle;
	} else if(param[0] == 'f') {
		genesis_context *gen = context->system;
		value = gen->vdp->frame;
	} else if (param[0] == 'p' && param[1] == 'c') {
		value = address;
	} else if ((param[0] == '0' && param[1] == 'x') || param[0] == '$') {
		char *after;
		uint32_t p_addr = strtol(param+(param[0] == '0' ? 2 : 1), &after, 16);
		if (after[0] == '.' && after[1] == 'l') {
			value = m68k_read_long(p_addr, context);
		} else if (after[0] == '.' && after[1] == 'b') {
			value = m68k_read_byte(p_addr, context);
		} else {
			value = m68k_read_word(p_addr, context);
		}
	} else if(param[0] == '(' && (param[1] == 'a' || param[1] == 'd') && param[2] >= '0' && param[2] <= '7' && param[3] == ')') {
		uint8_t reg = param[2] - '0';
		uint32_t p_addr = param[1] == 'a' ? context->aregs[reg] : context->dregs[reg];
		if (param[4] == '.' && param[5] == 'l') {
			value = m68k_read_long(p_addr, context);
		} else if (param[4] == '.' && param[5] == 'b') {
			value = m68k_read_byte(p_addr, context);
		} else {
			value = m68k_read_word(p_addr, context);
		}
	} else {
		fprintf(stderr, "Unrecognized parameter to p: %s\n", param);
		return;
	}
	printf(format, param, value);
}

#ifndef NO_Z80

void zdebugger_print(z80_context * context, char format_char, char * param)
{
	uint32_t value;
	char format[8];
	strcpy(format, "%s: %d\n");
	genesis_context *system = context->system;
	switch (format_char)
	{
	case 'x':
	case 'X':
	case 'd':
	case 'c':
		format[5] = format_char;
		break;
	case '\0':
		break;
	default:
		fprintf(stderr, "Unrecognized format character: %c\n", format_char);
	}
	switch (param[0])
	{
#ifndef NEW_CORE
	case 'a':
		if (param[1] == 'f') {
			if(param[2] == '\'') {
				value = context->alt_regs[Z80_A] << 8;
				value |= context->alt_flags[ZF_S] << 7;
				value |= context->alt_flags[ZF_Z] << 6;
				value |= context->alt_flags[ZF_H] << 4;
				value |= context->alt_flags[ZF_PV] << 2;
				value |= context->alt_flags[ZF_N] << 1;
				value |= context->alt_flags[ZF_C];
			} else {
				value = context->regs[Z80_A] << 8;
				value |= context->flags[ZF_S] << 7;
				value |= context->flags[ZF_Z] << 6;
				value |= context->flags[ZF_H] << 4;
				value |= context->flags[ZF_PV] << 2;
				value |= context->flags[ZF_N] << 1;
				value |= context->flags[ZF_C];
			}
		} else if(param[1] == '\'') {
			value = context->alt_regs[Z80_A];
		} else {
			value = context->regs[Z80_A];
		}
		break;
	case 'b':
		if (param[1] == 'c') {
			if(param[2] == '\'') {
				value = context->alt_regs[Z80_B] << 8;
				value |= context->alt_regs[Z80_C];
			} else {
				value = context->regs[Z80_B] << 8;
				value |= context->regs[Z80_C];
			}
		} else if(param[1] == '\'') {
			value = context->alt_regs[Z80_B];
		} else if(param[1] == 'a') {
			value = context->bank_reg << 15;
		} else {
			value = context->regs[Z80_B];
		}
		break;
	case 'c':
		if(param[1] == '\'') {
			value = context->alt_regs[Z80_C];
		} else if(param[1] == 'y') {
			value = context->current_cycle;
		} else {
			value = context->regs[Z80_C];
		}
		break;
	case 'd':
		if (param[1] == 'e') {
			if(param[2] == '\'') {
				value = context->alt_regs[Z80_D] << 8;
				value |= context->alt_regs[Z80_E];
			} else {
				value = context->regs[Z80_D] << 8;
				value |= context->regs[Z80_E];
			}
		} else if(param[1] == '\'') {
			value = context->alt_regs[Z80_D];
		} else {
			value = context->regs[Z80_D];
		}
		break;
	case 'e':
		if(param[1] == '\'') {
			value = context->alt_regs[Z80_E];
		} else {
			value = context->regs[Z80_E];
		}
		break;
	case 'f':
		if(param[2] == '\'') {
			value = context->alt_flags[ZF_S] << 7;
			value |= context->alt_flags[ZF_Z] << 6;
			value |= context->alt_flags[ZF_H] << 4;
			value |= context->alt_flags[ZF_PV] << 2;
			value |= context->alt_flags[ZF_N] << 1;
			value |= context->alt_flags[ZF_C];
		} else {
			value = context->flags[ZF_S] << 7;
			value |= context->flags[ZF_Z] << 6;
			value |= context->flags[ZF_H] << 4;
			value |= context->flags[ZF_PV] << 2;
			value |= context->flags[ZF_N] << 1;
			value |= context->flags[ZF_C];
		}
		break;
	case 'h':
		if (param[1] == 'l') {
			if(param[2] == '\'') {
				value = context->alt_regs[Z80_H] << 8;
				value |= context->alt_regs[Z80_L];
			} else {
				value = context->regs[Z80_H] << 8;
				value |= context->regs[Z80_L];
			}
		} else if(param[1] == '\'') {
			value = context->alt_regs[Z80_H];
		} else {
			value = context->regs[Z80_H];
		}
		break;
	case 'l':
		if(param[1] == '\'') {
			value = context->alt_regs[Z80_L];
		} else {
			value = context->regs[Z80_L];
		}
		break;
	case 'i':
		if(param[1] == 'x') {
			if (param[2] == 'h') {
				value = context->regs[Z80_IXH];
			} else if(param[2] == 'l') {
				value = context->regs[Z80_IXL];
			} else {
				value = context->regs[Z80_IXH] << 8;
				value |= context->regs[Z80_IXL];
			}
		} else if(param[1] == 'y') {
			if (param[2] == 'h') {
				value = context->regs[Z80_IYH];
			} else if(param[2] == 'l') {
				value = context->regs[Z80_IYL];
			} else {
				value = context->regs[Z80_IYH] << 8;
				value |= context->regs[Z80_IYL];
			}
		} else if(param[1] == 'n') {
			value = context->int_cycle;
		} else if(param[1] == 'f' && param[2] == 'f' && param[3] == '1') {
			value = context->iff1;
		} else if(param[1] == 'f' && param[2] == 'f' && param[3] == '2') {
			value = context->iff2;
		} else {
			value = context->im;
		}
		break;
#endif
	case 's':
		if (param[1] == 'p') {
			value = context->sp;
		}
		break;
	case '0':
		if (param[1] == 'x') {
			uint16_t p_addr = strtol(param+2, NULL, 16);
			value = read_byte(p_addr, (void **)context->mem_pointers, &context->options->gen, context);
		}
		break;
	}
	printf(format, param, value);
}

z80_context * zdebugger(z80_context * context, uint16_t address)
{
	static char last_cmd[1024];
	char input_buf[1024];
	static uint16_t branch_t;
	static uint16_t branch_f;
	z80inst inst;
	genesis_context *system = context->system;
	init_terminal();
	//Check if this is a user set breakpoint, or just a temporary one
	bp_def ** this_bp = find_breakpoint(&zbreakpoints, address);
	if (*this_bp) {
		printf("Z80 Breakpoint %d hit\n", (*this_bp)->index);
	} else {
		zremove_breakpoint(context, address);
	}
	uint8_t * pc = get_native_pointer(address, (void **)context->mem_pointers, &context->Z80_OPTS->gen);
	if (!pc) {
		fatal_error("Failed to get native pointer on entering Z80 debugger at address %X\n", address);
	}
	for (disp_def * cur = zdisplays; cur; cur = cur->next) {
		zdebugger_print(context, cur->format_char, cur->param);
	}
	uint8_t * after_pc = z80_decode(pc, &inst);
	z80_disasm(&inst, input_buf, address);
	printf("%X:\t%s\n", address, input_buf);
	uint16_t after = address + (after_pc-pc);
	int debugging = 1;
	while(debugging) {
		fputs(">", stdout);
		if (!fgets(input_buf, sizeof(input_buf), stdin)) {
			fputs("fgets failed", stderr);
			break;
		}
		strip_nl(input_buf);
		//hitting enter repeats last command
		if (input_buf[0]) {
			strcpy(last_cmd, input_buf);
		} else {
			strcpy(input_buf, last_cmd);
		}
		char * param;
		char format[8];
		uint32_t value;
		bp_def * new_bp;
		switch(input_buf[0])
		{
			case 'a':
				param = find_param(input_buf);
				if (!param) {
					fputs("a command requires a parameter\n", stderr);
					break;
				}
				value = strtol(param, NULL, 16);
				zinsert_breakpoint(context, value, (uint8_t *)zdebugger);
				debugging = 0;
				break;
			case 'b':
				param = find_param(input_buf);
				if (!param) {
					fputs("b command requires a parameter\n", stderr);
					break;
				}
				value = strtol(param, NULL, 16);
				zinsert_breakpoint(context, value, (uint8_t *)zdebugger);
				new_bp = malloc(sizeof(bp_def));
				new_bp->next = zbreakpoints;
				new_bp->address = value;
				new_bp->index = zbp_index++;
				new_bp->commands = NULL;
				zbreakpoints = new_bp;
				printf("Z80 Breakpoint %d set at %X\n", new_bp->index, value);
				break;
			case 'c':
				puts("Continuing");
				debugging = 0;
				break;
			case 'd':
				if (input_buf[1] == 'i') {
					char format_char = 0;
					for(int i = 2; input_buf[i] != 0 && input_buf[i] != ' '; i++) {
						if (input_buf[i] == '/') {
							format_char = input_buf[i+1];
							break;
						}
					}
					param = find_param(input_buf);
					if (!param) {
						fputs("display command requires a parameter\n", stderr);
						break;
					}
					zdebugger_print(context, format_char, param);
					add_display(&zdisplays, &zdisp_index, format_char, param);
				} else if (input_buf[1] == 'e' || input_buf[1] == ' ') {
					param = find_param(input_buf);
					if (!param) {
						fputs("delete command requires a parameter\n", stderr);
						break;
					}
					if (param[0] >= '0' && param[0] <= '9') {
						value = atoi(param);
						this_bp = find_breakpoint_idx(&zbreakpoints, value);
						if (!*this_bp) {
							fprintf(stderr, "Breakpoint %d does not exist\n", value);
							break;
						}
						new_bp = *this_bp;
						zremove_breakpoint(context, new_bp->address);
						*this_bp = new_bp->next;
						free(new_bp);
					} else if (param[0] == 'd') {
						param = find_param(param);
						if (!param) {
							fputs("delete display command requires a parameter\n", stderr);
							break;
						}
						remove_display(&zdisplays, atoi(param));
					}
				}
				break;
			case 'n':
				//TODO: Handle conditional branch instructions
				if (inst.op == Z80_JP) {
					if (inst.addr_mode == Z80_IMMED) {
						after = inst.immed;
					} else if (inst.ea_reg == Z80_HL) {
#ifndef NEW_CORE
						after = context->regs[Z80_H] << 8 | context->regs[Z80_L];
					} else if (inst.ea_reg == Z80_IX) {
						after = context->regs[Z80_IXH] << 8 | context->regs[Z80_IXL];
					} else if (inst.ea_reg == Z80_IY) {
						after = context->regs[Z80_IYH] << 8 | context->regs[Z80_IYL];
#endif
					}
				} else if(inst.op == Z80_JR) {
					after += inst.immed;
				} else if(inst.op == Z80_RET) {
					uint8_t *sp = get_native_pointer(context->sp, (void **)context->mem_pointers, &context->Z80_OPTS->gen);
					if (sp) {
						after = *sp;
						sp = get_native_pointer((context->sp + 1) & 0xFFFF, (void **)context->mem_pointers, &context->Z80_OPTS->gen);
						if (sp) {
							after |= *sp << 8;
						}
					}
				}
				zinsert_breakpoint(context, after, (uint8_t *)zdebugger);
				debugging = 0;
				break;
			case 'p':
				param = find_param(input_buf);
				if (!param) {
					fputs("p command requires a parameter\n", stderr);
					break;
				}
				zdebugger_print(context, input_buf[1] == '/' ? input_buf[2] : 0, param);
				break;
			case 'q':
				puts("Quitting");
				exit(0);
				break;
			case 's': {
				param = find_param(input_buf);
				if (!param) {
					fputs("s command requires a file name\n", stderr);
					break;
				}
				memmap_chunk const *ram_chunk = NULL;
				for (int i = 0; i < context->Z80_OPTS->gen.memmap_chunks; i++)
				{
					memmap_chunk const *cur = context->Z80_OPTS->gen.memmap + i;
					if (cur->flags & MMAP_WRITE) {
						ram_chunk = cur;
						break;
					}
				}
				if (ram_chunk) {
					uint32_t size = ram_chunk->end - ram_chunk->start;
					if (size > ram_chunk->mask) {
						size = ram_chunk->mask+1;
					}
					uint8_t *buf = get_native_pointer(ram_chunk->start, (void **)context->mem_pointers, &context->Z80_OPTS->gen);
					FILE * f = fopen(param, "wb");
					if (f) {
						if(fwrite(buf, 1, size, f) != size) {
							fputs("Error writing file\n", stderr);
						}
						fclose(f);
						printf("Wrote %d bytes to %s\n", size, param);
					} else {
						fprintf(stderr, "Could not open %s for writing\n", param);
					}
				} else {
					fputs("Failed to find a RAM memory chunk\n", stderr);
				}
				break;
			}
			case '?':
				print_z80_help();
				break;
			default:
				if (
					!context->Z80_OPTS->gen.debug_cmd_handler
					|| !context->Z80_OPTS->gen.debug_cmd_handler(&system->header, input_buf)
				) {
					fprintf(stderr, "Unrecognized debugger command %s\nUse '?' for help.\n", input_buf);
				}
				break;
		}
	}
	return context;
}

#endif

static uint32_t branch_t;
static uint32_t branch_f;

int run_debugger_command(m68k_context *context, uint32_t address, char *input_buf, m68kinst inst, uint32_t after)
{
	char * param;
	char format_char;
	genesis_context *system = context->system;
	uint32_t value;
	bp_def *new_bp, **this_bp;
	switch(input_buf[0])
	{
		case 'c':
			if (input_buf[1] == 0 || input_buf[1] == 'o' && input_buf[2] == 'n')
			{
				puts("Continuing");
				return 0;
			} else if (input_buf[1] == 'o' && input_buf[2] == 'm') {
				param = find_param(input_buf);
				if (!param) {
					fputs("com command requires a parameter\n", stderr);
					break;
				}
				bp_def **target = find_breakpoint_idx(&breakpoints, atoi(param));
				if (!target) {
					fprintf(stderr, "Breakpoint %s does not exist!\n", param);
					break;
				}
				printf("Enter commands for breakpoing %d, type end when done\n", atoi(param));
				char cmd_buf[1024];
				char *commands = NULL;
				for (;;)
				{
					fputs(">>", stdout);
					fflush(stdout);
					fgets(cmd_buf, sizeof(cmd_buf), stdin);
					if (strcmp(cmd_buf, "end\n")) {
						if (commands) {
							char *tmp = commands;
							commands = alloc_concat(commands, cmd_buf);
							free(tmp);
						} else {
							commands = strdup(cmd_buf);
						}
					} else {
						break;
					}
				}
				(*target)->commands = commands;
			} else {
			}
			break;
		case 'b':
			if (input_buf[1] == 't') {
				uint32_t stack = context->aregs[7];
				if (stack >= 0xE00000) {
					stack &= 0xFFFF;
					uint8_t non_adr_count = 0;
					do {
						uint32_t bt_address = system->work_ram[stack/2] << 16 | system->work_ram[stack/2+1];
						bt_address = get_instruction_start(context->options, bt_address - 2);
						if (bt_address) {
							stack += 4;
							non_adr_count = 0;
							uint16_t *bt_pc = NULL;
							if (bt_address < 0x400000) {
								bt_pc = system->cart + bt_address/2;
							} else if(bt_address > 0xE00000) {
								bt_pc = system->work_ram + (bt_address & 0xFFFF)/2;
							}
							m68k_decode(bt_pc, &inst, bt_address);
							m68k_disasm(&inst, input_buf);
							printf("%X: %s\n", bt_address, input_buf);
						} else {
							//non-return address value on stack can be word wide
							stack += 2;
							non_adr_count++;
						}
						stack &= 0xFFFF;
					} while (stack && non_adr_count < 6);
				}
			} else {
				param = find_param(input_buf);
				if (!param) {
					fputs("b command requires a parameter\n", stderr);
					break;
				}
				value = strtol(param, NULL, 16);
				insert_breakpoint(context, value, debugger);
				new_bp = malloc(sizeof(bp_def));
				new_bp->next = breakpoints;
				new_bp->address = value;
				new_bp->index = bp_index++;
				new_bp->commands = NULL;
				breakpoints = new_bp;
				printf("68K Breakpoint %d set at %X\n", new_bp->index, value);
			}
			break;
		case 'a':
			param = find_param(input_buf);
			if (!param) {
				fputs("a command requires a parameter\n", stderr);
				break;
			}
			value = strtol(param, NULL, 16);
			insert_breakpoint(context, value, debugger);
			return 0;
		case 'd':
			if (input_buf[1] == 'i') {
				format_char = 0;
				for(int i = 2; input_buf[i] != 0 && input_buf[i] != ' '; i++) {
					if (input_buf[i] == '/') {
						format_char = input_buf[i+1];
						break;
					}
				}
				param = find_param(input_buf);
				if (!param) {
					fputs("display command requires a parameter\n", stderr);
					break;
				}
				debugger_print(context, format_char, param, address);
				add_display(&displays, &disp_index, format_char, param);
			} else {
				param = find_param(input_buf);
				if (!param) {
					fputs("d command requires a parameter\n", stderr);
					break;
				}
				value = atoi(param);
				this_bp = find_breakpoint_idx(&breakpoints, value);
				if (!*this_bp) {
					fprintf(stderr, "Breakpoint %d does not exist\n", value);
					break;
				}
				new_bp = *this_bp;
				*this_bp = (*this_bp)->next;
				if (new_bp->commands) {
					free(new_bp->commands);
				}
				free(new_bp);
			}
			break;
		case 'p':
			format_char = 0;
			for(int i = 1; input_buf[i] != 0 && input_buf[i] != ' '; i++) {
				if (input_buf[i] == '/') {
					format_char = input_buf[i+1];
					break;
				}
			}
			param = find_param(input_buf);
			if (param) {
				debugger_print(context, format_char, param, address);
			} else {
				m68k_disasm(&inst, input_buf);
				printf("%X: %s\n", address, input_buf);
			}
			
			break;
		case 'n':
			if (inst.op == M68K_RTS) {
				after = m68k_read_long(context->aregs[7], context);
			} else if (inst.op == M68K_RTE || inst.op == M68K_RTR) {
				after = m68k_read_long(context->aregs[7] + 2, context);
			} else if(m68k_is_noncall_branch(&inst)) {
				if (inst.op == M68K_BCC && inst.extra.cond != COND_TRUE) {
					branch_f = after;
					branch_t = m68k_branch_target(&inst, context->dregs, context->aregs);
					insert_breakpoint(context, branch_t, debugger);
				} else if(inst.op == M68K_DBCC) {
					if ( inst.extra.cond == COND_FALSE) {
						if (context->dregs[inst.dst.params.regs.pri] & 0xFFFF) {
							after = m68k_branch_target(&inst, context->dregs, context->aregs);
						}
					} else {
						branch_t = after;
						branch_f = m68k_branch_target(&inst, context->dregs, context->aregs);
						insert_breakpoint(context, branch_f, debugger);
					}
				} else {
					after = m68k_branch_target(&inst, context->dregs, context->aregs);
				}
			}
			insert_breakpoint(context, after, debugger);
			return 0;
		case 'o':
			if (inst.op == M68K_RTS) {
				after = m68k_read_long(context->aregs[7], context);
			} else if (inst.op == M68K_RTE || inst.op == M68K_RTR) {
				after = m68k_read_long(context->aregs[7] + 2, context);
			} else if(m68k_is_noncall_branch(&inst)) {
				if (inst.op == M68K_BCC && inst.extra.cond != COND_TRUE) {
					branch_t = m68k_branch_target(&inst, context->dregs, context->aregs)  & 0xFFFFFF;
					if (branch_t < after) {
							branch_t = 0;
					} else {
						branch_f = after;
						insert_breakpoint(context, branch_t, debugger);
					}
				} else if(inst.op == M68K_DBCC) {
					uint32_t target = m68k_branch_target(&inst, context->dregs, context->aregs)  & 0xFFFFFF;
					if (target > after) {
						if (inst.extra.cond == COND_FALSE) {
							after = target;
						} else {
							branch_f = target;
							branch_t = after;
							insert_breakpoint(context, branch_f, debugger);
						}
					}
				} else {
					after = m68k_branch_target(&inst, context->dregs, context->aregs) & 0xFFFFFF;
				}
			}
			insert_breakpoint(context, after, debugger);
			return 0;
		case 's':
			if (input_buf[1] == 'e') {
				param = find_param(input_buf);
				if (!param) {
					fputs("Missing destination parameter for set\n", stderr);
					return 1;
				}
				char *val = find_param(param);
				if (!val) {
					fputs("Missing value parameter for set\n", stderr);
					return 1;
				}
				long int_val;
				int reg_num;
				switch (val[0])
				{
				case 'd':
				case 'a':
					reg_num = val[1] - '0';
					if (reg_num < 0 || reg_num > 8) {
						fprintf(stderr, "Invalid register %s\n", val);
						return 1;
					}
					int_val = (val[0] == 'd' ? context->dregs : context->aregs)[reg_num];
					break;
				case '$':
					int_val = strtol(val+1, NULL, 16);
					break;
				case '0':
					if (val[1] == 'x') {
						int_val = strtol(val+2, NULL, 16);
						break;
					}
				default:
					int_val = strtol(val, NULL, 10);
				}
				switch(param[0])
				{
				case 'd':
				case 'a':
					reg_num = param[1] - '0';
					if (reg_num < 0 || reg_num > 8) {
						fprintf(stderr, "Invalid register %s\n", param);
						return 1;
					}
					(param[0] == 'd' ? context->dregs : context->aregs)[reg_num] = int_val;
					break;
				default:
					fprintf(stderr, "Invalid destinatino %s\n", param);
				}
				break;
			} else if (input_buf[1] == 'r') {
				system->header.soft_reset(&system->header);
				return 0;
			} else {
				if (inst.op == M68K_RTS) {
					after = m68k_read_long(context->aregs[7], context);
				} else if (inst.op == M68K_RTE || inst.op == M68K_RTR) {
					after = m68k_read_long(context->aregs[7] + 2, context);
				} else if(m68k_is_branch(&inst)) {
					if (inst.op == M68K_BCC && inst.extra.cond != COND_TRUE) {
						branch_f = after;
						branch_t = m68k_branch_target(&inst, context->dregs, context->aregs) & 0xFFFFFF;
						insert_breakpoint(context, branch_t, debugger);
					} else if(inst.op == M68K_DBCC) {
						if (inst.extra.cond == COND_FALSE) {
							if (context->dregs[inst.dst.params.regs.pri] & 0xFFFF) {
								after = m68k_branch_target(&inst, context->dregs, context->aregs);
							}
						} else {
							branch_t = after;
							branch_f = m68k_branch_target(&inst, context->dregs, context->aregs);
							insert_breakpoint(context, branch_f, debugger);
						}
					} else {
						after = m68k_branch_target(&inst, context->dregs, context->aregs) & 0xFFFFFF;
					}
				}
				insert_breakpoint(context, after, debugger);
				return 0;
			}
		case 'v': {
			genesis_context * gen = context->system;
			//VDP debug commands
			switch(input_buf[1])
			{
			case 's':
				vdp_print_sprite_table(gen->vdp);
				break;
			case 'r':
				vdp_print_reg_explain(gen->vdp);
				break;
			}
			break;
		}
		case 'y': {
			genesis_context * gen = context->system;
			//YM-2612 debug commands
			switch(input_buf[1])
			{
			case 'c':
				if (input_buf[2] == ' ') {
					int channel = atoi(input_buf+3)-1;
					ym_print_channel_info(gen->ym, channel);
				} else {
					for (int i = 0; i < 6; i++) {
						ym_print_channel_info(gen->ym, i);
					}
				}
				break;
			case 't':
				ym_print_timer_info(gen->ym);
				break;
			}
			break;
		}
#ifndef NO_Z80
		case 'z': {
			genesis_context * gen = context->system;
			//Z80 debug commands
			switch(input_buf[1])
			{
			case 'b':
				param = find_param(input_buf);
				if (!param) {
					fputs("zb command requires a parameter\n", stderr);
					break;
				}
				value = strtol(param, NULL, 16);
				zinsert_breakpoint(gen->z80, value, (uint8_t *)zdebugger);
				new_bp = malloc(sizeof(bp_def));
				new_bp->next = zbreakpoints;
				new_bp->address = value;
				new_bp->index = zbp_index++;
				zbreakpoints = new_bp;
				printf("Z80 Breakpoint %d set at %X\n", new_bp->index, value);
				break;
			case 'p':
				param = find_param(input_buf);
				if (!param) {
					fputs("zp command requires a parameter\n", stderr);
					break;
				}
				zdebugger_print(gen->z80, input_buf[2] == '/' ? input_buf[3] : 0, param);
			}
			break;
		}
#endif
		case '?':
			print_m68k_help();
			break;
		case 'q':
			puts("Quitting");
			exit(0);
			break;
		default:
			fprintf(stderr, "Unrecognized debugger command %s\nUse '?' for help.\n", input_buf);
			break;
	}
	return 1;
}

void print_m68k_help()
{
	printf("M68k Debugger Commands\n");
	printf("    b ADDRESS            - Set a breakpoint at ADDRESS\n");
	printf("    d BREAKPOINT         - Delete a 68K breakpoint\n");
	printf("    co BREAKPOINT        - Run a list of debugger commands each time\n");
	printf("                           BREAKPOINT is hit\n");
	printf("    a ADDRESS            - Advance to address\n");
	printf("    n                    - Advance to next instruction\n");
	printf("    o                    - Advance to next instruction ignoring branches to\n");
	printf("                           lower addresses (good for breaking out of loops)\n");
	printf("    s                    - Advance to next instruction (follows bsr/jsr)\n");
	printf("    se REG|ADDRESS VALUE - Set value\n");
	printf("    sr                   - Soft reset\n");
	printf("    c                    - Continue\n");
	printf("    bt                   - Print a backtrace\n");
	printf("    p[/(x|X|d|c)] VALUE  - Print a register or memory location\n");
	printf("    di[/(x|X|d|c)] VALUE - Print a register or memory location each time\n");
	printf("                           a breakpoint is hit\n");
	printf("    vs                   - Print VDP sprite list\n");
	printf("    vr                   - Print VDP register info\n");
	printf("    yc [CHANNEL NUM]     - Print YM-2612 channel info\n");
	printf("    yt                   - Print YM-2612 timer info\n");
	printf("    zb ADDRESS           - Set a Z80 breakpoint\n");
	printf("    zp[/(x|X|d|c)] VALUE - Display a Z80 value\n");
	printf("    ?                    - Display help\n");
	printf("    q                    - Quit BlastEm\n");
}

void print_z80_help()
{
	printf("Z80 Debugger Commands\n");
	printf("    b  ADDRESS           - Set a breakpoint at ADDRESS\n");
	printf("    de BREAKPOINT        - Delete a Z80 breakpoint\n");
	printf("    a  ADDRESS           - Advance to address\n");
	printf("    n                    - Advance to next instruction\n");
	printf("    c                    - Continue\n");
	printf("    p[/(x|X|d|c)] VALUE  - Print a register or memory location\n");
	printf("    di[/(x|X|d|c)] VALUE - Print a register or memory location each time\n");
	printf("                           a breakpoint is hit\n");
	printf("    q                    - Quit BlastEm\n");
}

void debugger(m68k_context * context, uint32_t address)
{
	static char last_cmd[1024];
	char input_buf[1024];
	m68kinst inst;

	init_terminal();

	sync_components(context, 0);
	genesis_context *gen = context->system;
	vdp_force_update_framebuffer(gen->vdp);
	//probably not necessary, but let's play it safe
	address &= 0xFFFFFF;
	if (address == branch_t) {
		bp_def ** f_bp = find_breakpoint(&breakpoints, branch_f);
		if (!*f_bp) {
			remove_breakpoint(context, branch_f);
		}
		branch_t = branch_f = 0;
	} else if(address == branch_f) {
		bp_def ** t_bp = find_breakpoint(&breakpoints, branch_t);
		if (!*t_bp) {
			remove_breakpoint(context, branch_t);
		}
		branch_t = branch_f = 0;
	}

	uint16_t * pc = get_native_pointer(address, (void **)context->mem_pointers, &context->options->gen);
	if (!pc) {
		fatal_error("Entered 68K debugger at address %X\n", address);
	}
	uint16_t * after_pc = m68k_decode(pc, &inst, address);
	uint32_t after = address + (after_pc-pc)*2;
	int debugging = 1;
	//Check if this is a user set breakpoint, or just a temporary one
	bp_def ** this_bp = find_breakpoint(&breakpoints, address);
	if (*this_bp) {

		if ((*this_bp)->commands)
		{
			char *commands = strdup((*this_bp)->commands);
			char *copy = commands;

			while (debugging && *commands)
			{
				char *cmd = commands;
				strip_nl(cmd);
				commands += strlen(cmd) + 1;
				debugging = run_debugger_command(context, address, cmd, inst, after);
			}
			free(copy);
		}
		if (debugging) {
			printf("68K Breakpoint %d hit\n", (*this_bp)->index);
		} else {
			return;
		}
	} else {
		remove_breakpoint(context, address);
	}
	for (disp_def * cur = displays; cur; cur = cur->next) {
		debugger_print(context, cur->format_char, cur->param, address);
	}
	m68k_disasm(&inst, input_buf);
	printf("%X: %s\n", address, input_buf);
#ifdef _WIN32
#define prompt 1
#else
	int prompt = 1;
	fd_set read_fds;
	FD_ZERO(&read_fds);
	struct timeval timeout;
#endif
	while (debugging) {
		if (prompt) {
			fputs(">", stdout);
			fflush(stdout);
		}
		process_events();
#ifndef _WIN32
		timeout.tv_sec = 0;
		timeout.tv_usec = 16667;
		FD_SET(fileno(stdin), &read_fds);
		if(select(fileno(stdin) + 1, &read_fds, NULL, NULL, &timeout) < 1) {
			prompt = 0;
			continue;
		} else {
			prompt = 1;
		}
#endif
		if (!fgets(input_buf, sizeof(input_buf), stdin)) {
			fputs("fgets failed", stderr);
			break;
		}
		strip_nl(input_buf);
		//hitting enter repeats last command
		if (input_buf[0]) {
			strcpy(last_cmd, input_buf);
		} else {
			strcpy(input_buf, last_cmd);
		}
		debugging = run_debugger_command(context, address, input_buf, inst, after);
	}
	return;
}