/*
 * Copyright © 2008 Keith Packard <keithp@keithp.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 */

#include "s51.h"

static enum command_result
parse_int(char *value, int *result)
{
	char *endptr;

	*result = strtol(value, &endptr, 0);
	if (endptr == value)
		return command_syntax;
	return command_success;
}

static enum command_result
parse_uint16(char *value, uint16_t *uint16)
{
	int	v;
	enum command_result result;

	result = parse_int(value, &v);
	if (result != command_success)
		return command_error;
	if (v < 0 || v > 0xffff)
		return command_error;
	*uint16 = v;
	return command_success;
}

enum command_result
command_quit (int argc, char **argv)
{
	exit(0);
	return command_error;
}

static void
dump_bytes(uint8_t *memory, int length, uint16_t start)
{
	int group, i;
	
	for (group = 0; group < length; group += 8) {
		s51_printf("0x%04x ", start + group);
		for (i = group; i < length && i < group + 8; i++)
			s51_printf("%02x ", memory[i]);
		for (; i < group + 8; i++)
			s51_printf("   ");
		for (i = group; i < length && i < group + 8; i++) {
			if (isascii(memory[i]) && isprint(memory[i]))
				s51_printf("%c", memory[i]);
			else
				s51_printf(".");
		}
		s51_printf("\n");
	}
}

enum command_result
command_di (int argc, char **argv)
{
	uint16_t start, end;
	uint8_t	memory[65536];
	uint8_t status;
	int length;
	
	if (argc != 3)
		return command_error;
	if (parse_uint16(argv[1], &start) != command_success)
		return command_error;
	if (parse_uint16(argv[2], &end) != command_success)
		return command_error;
	length = (int) end - (int) start + 1;
	status = ccdbg_read_memory(s51_dbg, start + 0xff00, memory, length);
	dump_bytes(memory, length, start);
	return command_success;
}

enum command_result
command_ds (int argc, char **argv)
{
	uint16_t start, end;
	uint8_t	memory[65536];
	uint8_t status;
	int length;
	
	if (argc != 3)
		return command_error;
	if (parse_uint16(argv[1], &start) != command_success)
		return command_error;
	if (parse_uint16(argv[2], &end) != command_success)
		return command_error;
	length = (int) end - (int) start + 1;
	status = ccdbg_read_memory(s51_dbg, start + 0xdf00, memory, length);
	dump_bytes(memory, length, start);
	return command_success;
}

enum command_result
command_dx (int argc, char **argv)
{
	uint16_t start, end;
	uint8_t	memory[65536];
	uint8_t status;
	int length;
	
	if (argc != 3)
		return command_error;
	if (parse_uint16(argv[1], &start) != command_success)
		return command_error;
	if (parse_uint16(argv[2], &end) != command_success)
		return command_error;
	length = (int) end - (int) start + 1;
	status = ccdbg_read_memory(s51_dbg, start, memory, length);
	dump_bytes(memory, length, start);
	return command_success;
}

enum command_result
command_set (int argc, char **argv)
{
	return command_error;
}

enum command_result
command_dump (int argc, char **argv)
{
	return command_error;
}

enum command_result
command_file (int argc, char **argv)
{
	if (argc != 2)
		return command_error;
	s51_printf("some words read from %s\n", argv[1]);
	return command_success;
}

enum command_result
command_pc (int argc, char **argv)
{
	uint16_t	pc;
	if (argv[1]) {
		enum command_result result;
		result = parse_uint16(argv[1], &pc);
		if (result != command_success)
			return result;
		ccdbg_set_pc(s51_dbg, pc);
	} else {
		pc = ccdbg_get_pc(s51_dbg);
		s51_printf("   0x%04x 00\n", pc);
	}
	return command_success;
}

struct cc_break {
	int		enabled;
	int		temporary;
	uint16_t	address;
};

#define CC_NUM_BREAKPOINTS 4

static struct cc_break	breakpoints[CC_NUM_BREAKPOINTS];

static void
disable_breakpoint(int b)
{
	uint8_t status;
	
	status = ccdbg_set_hw_brkpnt(s51_dbg, b, 0, breakpoints[b].address);
	if (status != 0x00 && status != 0xff)
		s51_printf("disable_breakpoint status 0x%02x\n", status);
}

static void
enable_breakpoint(int b)
{
	uint8_t status;
	
	status = ccdbg_set_hw_brkpnt(s51_dbg, b, 1, breakpoints[b].address);
	if (status != 0xff)
		s51_printf("enable_breakpoint status 0x%02x\n", status);
}

enum command_result
set_breakpoint(uint16_t address, int temporary)
{
	int b;
	uint8_t status;
	for (b = 0; b < CC_NUM_BREAKPOINTS; b++) {
		if (breakpoints[b].enabled == 0)
			break;
		if (breakpoints[b].address == address)
			break;
	}
	if (b == CC_NUM_BREAKPOINTS) {
		s51_printf("Error: too many breakpoints requested\n");
		return command_success;
	}
	if (breakpoints[b].enabled == 0) {
		breakpoints[b].address = address;
		enable_breakpoint(b);
	}
	++breakpoints[b].enabled;
	s51_printf("Breakpoint %d at 0x%04x\n", b, address);
	breakpoints[b].temporary += temporary;
	return command_success;
}

enum command_result
clear_breakpoint(uint16_t address, int temporary)
{
	int b;
	uint8_t status;

	for (b = 0; b < CC_NUM_BREAKPOINTS; b++) {
		if (breakpoints[b].enabled != 0 &&
		    ((breakpoints[b].temporary != 0) == (temporary != 0)) &&
		    breakpoints[b].address == address)
			break;
	}
	if (b == CC_NUM_BREAKPOINTS) {
		s51_printf("Error: no matching breakpoint found\n");
		return command_success;
	}
	--breakpoints[b].enabled;
	breakpoints[b].temporary -= temporary;
	if (breakpoints[b].enabled == 0) {
		disable_breakpoint(b);
		breakpoints[b].address = -1;
	}
	return command_success;
}


int
find_breakpoint(uint16_t address)
{
	int b;

	for (b = 0; b < CC_NUM_BREAKPOINTS; b++)
		if (breakpoints[b].enabled && breakpoints[b].address == address)
			break;
	if (b == CC_NUM_BREAKPOINTS)
		return -1;
	if (breakpoints[b].temporary)
		clear_breakpoint(address, 1);
}

enum command_result
command_break (int argc, char **argv)
{
	int b;
	uint16_t address;
	enum command_result result;

	if (argc == 1) {
		for (b = 0; b < CC_NUM_BREAKPOINTS; b++)
			if (breakpoints[b].enabled)
				s51_printf("Breakpoint %d 0x%04x\n",
					b, breakpoints[b].address);
		return command_success;
	}
	if (argc != 2)
		return command_error;
	result = parse_uint16(argv[1], &address);
	if (result != command_success)
		return result;

	return set_breakpoint(address, 0);
}

enum command_result
command_clear (int argc, char **argv)
{
	int b;
	uint16_t address;
	enum command_result result;

	if (argc != 2)
		return command_error;
	result = parse_uint16(argv[1], &address);
	if (result != command_success)
		return result;
	return clear_breakpoint(address, 0);
}

void
cc_stopped(uint8_t status)
{
	uint16_t pc;
	int b;
	int code;
	char *reason;

	pc = ccdbg_get_pc(s51_dbg);
	if (status & CC_STATUS_CPU_HALTED) {
		if ((status & CC_STATUS_HALT_STATUS) != 0) {
			pc = pc - 1;
			code = 104;
			reason = "Breakpoint";
			ccdbg_set_pc(s51_dbg, pc);
		} else {
			code = 105;
			reason = "Interrupt";
		}
		s51_printf("Stop at 0x%04x: (%d) %s\n",
			pc, code, reason);
	}
}

uint8_t
cc_step(uint16_t pc)
{
	int b;
	uint8_t status;

	b = find_breakpoint(pc);
	if (b != -1)
		disable_breakpoint(b);
	status = ccdbg_step_instr(s51_dbg);
	if (b != -1)
		enable_breakpoint(b);
	return status;
}

enum command_result
command_run (int argc, char **argv)
{
	uint16_t start, end;
	enum command_result result;
	uint16_t pc;
	uint8_t status;
	int b;
	
	if (argv[1]) {
		result = parse_uint16(argv[1], &start);
		if (result != command_success)
			return result;
		if (argv[2]) {
			result = parse_uint16(argv[2], &end);
			if (result != command_success)
				return result;
		}
		ccdbg_set_pc(s51_dbg, start);
	}
	else
		start = ccdbg_get_pc(s51_dbg);
	s51_printf("Resume at 0x%04x\n", start);
	pc = start;
	b = find_breakpoint(pc);
	if (b != -1) {
		cc_step(pc);
		pc = ccdbg_get_pc(s51_dbg);
		if (find_breakpoint(pc) != -1) {
			status = ccdbg_read_status(s51_dbg);
			cc_stopped(status);
			return command_success;
		}
	}
	ccdbg_resume(s51_dbg);
	result = cc_wait();
	return result;
}

enum command_result
command_next (int argc, char **argv)
{
	return command_step(argc, argv);
}

enum command_result
command_step (int argc, char **argv)
{
	uint16_t pc;
	uint8_t	opcode;
	uint8_t a;

	a = cc_step(ccdbg_get_pc(s51_dbg));
	s51_printf(" ACC= 0x%02x\n", a);
	pc = ccdbg_get_pc(s51_dbg);
	ccdbg_read_memory(s51_dbg, pc, &opcode, 1);
	s51_printf(" ? 0x%04x %02x\n", pc, opcode);
	return command_success;
}

enum command_result
command_load (int argc, char **argv)
{
	return command_error;
}

enum command_result
command_halt (int argc, char **argv)
{
	uint16_t	pc;
	ccdbg_halt(s51_dbg);
	pc = ccdbg_get_pc(s51_dbg);
	s51_printf("Halted at 0x%04x\n", pc);
	return command_success;
}

enum command_result
command_reset (int argc, char **argv)
{
	ccdbg_debug_mode(s51_dbg);
	return command_success;
}

enum command_result
command_status(int argc, char **argv)
{
	uint8_t	status;

	status = ccdbg_read_status(s51_dbg);
	if ((status & CC_STATUS_CHIP_ERASE_DONE) == 0)
		s51_printf("\tChip erase in progress\n");
	if (status & CC_STATUS_PCON_IDLE)
		s51_printf("\tCPU is idle (clock gated)\n");
	if (status & CC_STATUS_CPU_HALTED)
		s51_printf("\tCPU halted\n");
	else
		s51_printf("\tCPU running\n");
	if ((status & CC_STATUS_POWER_MODE_0) == 0)
		s51_printf("\tPower Mode 1-3 selected\n");
	if (status & CC_STATUS_HALT_STATUS)
		s51_printf("\tHalted by software or hw breakpoint\n");
	else
		s51_printf("\tHalted by debug command\n");
	if (status & CC_STATUS_DEBUG_LOCKED)
		s51_printf("\tDebug interface is locked\n");
	if ((status & CC_STATUS_OSCILLATOR_STABLE) == 0)
		s51_printf("\tOscillators are not stable\n");
	if (status & CC_STATUS_STACK_OVERFLOW)
		s51_printf("\tStack overflow\n");
	return command_success;
}

enum command_result
cc_wait(void)
{
	for(;;) {
		uint8_t status;
		status = ccdbg_read_status(s51_dbg);
		if (status & CC_STATUS_CPU_HALTED) {
			cc_stopped(status);
			return command_success;
		}
		if (s51_interrupted || s51_check_input()) {
			
			ccdbg_halt(s51_dbg);
			status = ccdbg_read_status(s51_dbg);
			cc_stopped(status);
			return command_interrupt;
		}
	}
}