/*
 Copyright 2013 Michael Pavone
 This file is part of BlastEm. 
 BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
*/
#include "68kinst.h"
#include <stdio.h>
#include <stdlib.h>

uint8_t visited[(16*1024*1024)/16];
uint8_t label[(16*1024*1024)/8];

void visit(uint32_t address)
{
	address &= 0xFFFFFF;
	visited[address/16] |= 1 << ((address / 2) % 8);
}

void reference(uint32_t address)
{
	address &= 0xFFFFFF;
	//printf("referenced: %X\n", address);
	label[address/16] |= 1 << (address % 8);
}

uint8_t is_visited(uint32_t address)
{
	address &= 0xFFFFFF;
	return visited[address/16] & (1 << ((address / 2) % 8));
}

uint8_t is_label(uint32_t address)
{
	address &= 0xFFFFFF;
	return label[address/16] & (1 << (address % 8));
}

typedef struct deferred {
	uint32_t address;
	struct deferred *next;
} deferred;

deferred * defer(uint32_t address, deferred * next)
{
	if (is_visited(address)) {
		return next;
	}
	//printf("deferring %X\n", address);
	deferred * d = malloc(sizeof(deferred));
	d->address = address;
	d->next = next;
	return d;
}

void check_reference(m68kinst * inst, m68k_op_info * op)
{
	switch(op->addr_mode)
	{
	case MODE_PC_DISPLACE:
		reference(inst->address + 2 + op->params.regs.displacement);
		break;
	case MODE_ABSOLUTE:
	case MODE_ABSOLUTE_SHORT:
		reference(op->params.immed);
		break;
	}
}

uint8_t labels = 0;
uint8_t addr = 0;
uint8_t only = 0;

int main(int argc, char ** argv)
{
	long filesize;
	unsigned short *filebuf;
	char disbuf[1024];
	m68kinst instbuf;
	unsigned short * cur;
	FILE * f = fopen(argv[1], "rb");
	fseek(f, 0, SEEK_END);
	filesize = ftell(f);
	fseek(f, 0, SEEK_SET);
	filebuf = malloc(filesize);
	fread(filebuf, 2, filesize/2, f);
	fclose(f);
	deferred *def = NULL, *tmpd;
	for(uint8_t opt = 2; opt < argc; ++opt) {
		if (argv[opt][0] == '-') {
			FILE * address_log;
			switch (argv[opt][1])
			{
			case 'l':
				labels = 1;
				break;
			case 'a':
				addr = 1;
				break;
			case 'o':
				only = 1;
				break;
			case 'f':
				opt++;
				if (opt >= argc) {
					fputs("-f must be followed by a filename\n", stderr);
					exit(1);
				}
				address_log = fopen(argv[opt], "r");
				if (!address_log) {
					fprintf(stderr, "Failed to open %s for reading\n", argv[opt]);
					exit(1);
				}
				while (fgets(disbuf, sizeof(disbuf), address_log)) {
				 	if (disbuf[0]) {
						uint32_t address = strtol(disbuf, NULL, 16);
						if (address) {
							def = defer(address, def);
							reference(address);
						}
					}
				}
			}
		} else {
			uint32_t address = strtol(argv[opt], NULL, 16);
			def = defer(address, def);
			reference(address);
		}
	}
	for(cur = filebuf; cur - filebuf < (filesize/2); ++cur)
	{
		*cur = (*cur >> 8) | (*cur << 8);
	}
	uint32_t start = filebuf[2] << 16 | filebuf[3], tmp_addr;
	uint32_t int_2 = filebuf[0x68/2] << 16 | filebuf[0x6A/2];
	uint32_t int_4 = filebuf[0x70/2] << 16 | filebuf[0x72/2];
	uint32_t int_6 = filebuf[0x78/2] << 16 | filebuf[0x7A/2];
	uint16_t *encoded, *next;
	uint32_t size;
	if (!def || !only) {
		def = defer(start, def);
		def = defer(int_2, def);
		def = defer(int_4, def);
		def = defer(int_6, def);
	}
	uint32_t address;
	while(def) {
		do {
			encoded = NULL;
			address = def->address;
			if (!is_visited(address)) {
				encoded = filebuf + address/2;
			}
			tmpd = def;
			def = def->next;
			free(tmpd);
		} while(def && encoded == NULL);
		if (!encoded) {
			break;
		}
		for(;;) {
			if (address > filesize) {
				break;
			}
			visit(address);
			next = m68k_decode(encoded, &instbuf, address);
			address += (next-encoded)*2;
			encoded = next;
			//m68k_disasm(&instbuf, disbuf);
			//printf("%X: %s\n", instbuf.address, disbuf);
			check_reference(&instbuf, &(instbuf.src));
			check_reference(&instbuf, &(instbuf.dst));
			if (instbuf.op == M68K_ILLEGAL || instbuf.op == M68K_RTS || instbuf.op == M68K_RTE || instbuf.op == M68K_INVALID) {
				break;
			}
			if (instbuf.op == M68K_BCC || instbuf.op == M68K_DBCC || instbuf.op == M68K_BSR) {
				if (instbuf.op == M68K_BCC && instbuf.extra.cond == COND_TRUE) {
					address = instbuf.address + 2 + instbuf.src.params.immed;
					encoded = filebuf + address/2;
					reference(address);
					if (is_visited(address)) {
						break;
					}
				} else {
					tmp_addr = instbuf.address + 2 + instbuf.src.params.immed;
					reference(tmp_addr);
					def = defer(tmp_addr, def);
				}
			} else if(instbuf.op == M68K_JMP) {
				if (instbuf.src.addr_mode == MODE_ABSOLUTE || instbuf.src.addr_mode == MODE_ABSOLUTE_SHORT) {
					address = instbuf.src.params.immed;
					encoded = filebuf + address/2;
					if (is_visited(address)) {
						break;
					}
				} else if (instbuf.src.addr_mode = MODE_PC_DISPLACE) {
					address = instbuf.src.params.regs.displacement + instbuf.address + 2;
					encoded = filebuf + address/2;
					if (is_visited(address)) {
						break;
					}
				} else {
					break;
				}
			} else if(instbuf.op == M68K_JSR) {
				if (instbuf.src.addr_mode == MODE_ABSOLUTE || instbuf.src.addr_mode == MODE_ABSOLUTE_SHORT) {
					def = defer(instbuf.src.params.immed, def);
				} else if (instbuf.src.addr_mode == MODE_PC_DISPLACE) {
					def = defer(instbuf.src.params.regs.displacement + instbuf.address + 2, def);
				}
			}
		}
	}
	if (labels) {
		for (address = filesize; address < (16*1024*1024); address++) {
			if (is_label(address)) {
				printf("ADR_%X equ $%X\n", address, address);
			}
		}
		puts("");
	}
	for (address = 0; address < filesize; address+=2) {
		if (is_visited(address)) {
			encoded = filebuf + address/2;
			m68k_decode(encoded, &instbuf, address);
			if (labels) {
				m68k_disasm_labels(&instbuf, disbuf);
				if (address == start) {
					puts("start:");
				}
				if(address == int_2) {
					puts("int_2:");
				}
				if(address == int_4) {
					puts("int_4:");
				}
				if(address == int_6) {
					puts("int_6:");
				}
				if (is_label(instbuf.address)) {
					printf("ADR_%X:\n", instbuf.address);
				}
				if (addr) {
					printf("\t%s\t;%X\n", disbuf, instbuf.address);
				} else {
					printf("\t%s\n", disbuf);
				}
			} else {
				m68k_disasm(&instbuf, disbuf);
				printf("%X: %s\n", instbuf.address, disbuf);
			}
		}
	}
	return 0;
}