// SPDX-FileCopyrightText: 2015-2019 pancake <pancake@nopcode.org>
// SPDX-FileCopyrightText: 2015-2019 condret <condr3t@protonmail.com>
// SPDX-FileCopyrightText: 2015-2019 riq <ricardoquesada@gmail.com>
// SPDX-FileCopyrightText: 2015-2019 qnix <qnix@0x80.org>
// SPDX-FileCopyrightText: 2015-2019 astuder <github@adrianstuder.com>
// SPDX-License-Identifier: LGPL-3.0-only

#include <rz_lib.h>
#include <string.h>

#include "8051_disas.h"
#include "8051_ops.h"

static const char *_8051_regs[] = {
	"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", // 0x00
	0, 0, 0, 0, 0, 0, 0, 0, // 0x08
	0, 0, 0, 0, 0, 0, 0, 0, // 0x10
	0, 0, 0, 0, 0, 0, 0, 0, // 0x18
	0, 0, 0, 0, 0, 0, 0, 0, // 0x20
	0, 0, 0, 0, 0, 0, 0, 0, // 0x28
	0, 0, 0, 0, 0, 0, 0, 0, // 0x30
	0, 0, 0, 0, 0, 0, 0, 0, // 0x38
	0, 0, 0, 0, 0, 0, 0, 0, // 0x40
	0, 0, 0, 0, 0, 0, 0, 0, // 0x48
	0, 0, 0, 0, 0, 0, 0, 0, // 0x50
	0, 0, 0, 0, 0, 0, 0, 0, // 0x58
	0, 0, 0, 0, 0, 0, 0, 0, // 0x60
	0, 0, 0, 0, 0, 0, 0, 0, // 0x68
	0, 0, 0, 0, 0, 0, 0, 0, // 0x70
	0, 0, 0, 0, 0, 0, 0, 0, // 0x78
	"p0", "sp", "dpl", "dph", 0, 0, 0, "pcon", // 0x80
	"tcon", "tmod", "tl0", "tl1", "th0", "th1", 0, 0, // 0x88
	"p1", 0, 0, 0, 0, 0, 0, 0, // 0x90
	"scon", "sbuf", 0, 0, 0, 0, 0, 0, // 0x98
	"p2", 0, 0, 0, 0, 0, 0, 0, // 0xa0
	"ie", 0, 0, 0, 0, 0, 0, 0, // 0xa8
	"p3", 0, 0, 0, 0, 0, 0, 0, // 0xb0
	"ip", 0, 0, 0, 0, 0, 0, 0, // 0xb8
	0, 0, 0, 0, 0, 0, 0, 0, // 0xc0
	0, 0, 0, 0, 0, 0, 0, 0, // 0xc8
	"psw", 0, 0, 0, 0, 0, 0, 0, // 0xd0
	0, 0, 0, 0, 0, 0, 0, 0, // 0xd8
	"acc", 0, 0, 0, 0, 0, 0, 0, // 0xe0
	0, 0, 0, 0, 0, 0, 0, 0, // 0xe8
	"b", 0, 0, 0, 0, 0, 0, 0, // 0xf0
	0, 0, 0, 0, 0, 0, 0, 0 // 0xf8
};

static char *_replace_register(char *disasm, ut8 arg, ut8 val) {
	char key[10];
	char subst[10];
	if (arg == A_DIRECT) {
		if (_8051_regs[val]) {
			disasm = rz_str_replace(disasm,
				rz_strf(key, " 0x%02x", val),
				rz_strf(subst, " %s", _8051_regs[val]),
				0);
		}
	} else if (arg == A_BIT) {
		val = arg_bit(val);
		if (_8051_regs[val]) {
			disasm = rz_str_replace(disasm,
				rz_strf(key, "0x%02x.", val),
				rz_strf(subst, "%s.", _8051_regs[val]),
				0);
		}
	}
	return disasm;
}

char *rz_8051_disas(ut64 pc, const ut8 *buf, int len, int *olen) {
	int i = 0;
	while (_8051_ops[i].string && _8051_ops[i].op != (buf[0] & ~_8051_ops[i].mask)) {
		i++;
	}

	if (_8051_ops[i].string) {
		// valid opcodes
		const char *name = _8051_ops[i].string;
		ut8 mask = _8051_ops[i].mask;
		ut8 arg1 = _8051_ops[i].arg1;
		ut8 arg2 = _8051_ops[i].arg2;
		ut8 arg3 = _8051_ops[i].arg3;
		ut8 oplen = _8051_ops[i].len;
		ut8 val1 = 0, val2 = 0;
		char *disasm = 0;

		switch (oplen) {
		case 1:
			if ((arg1 == A_RI) || (arg1 == A_RN)) {
				// op @Ri; op Rn
				disasm = rz_str_newf(name, buf[0] & mask);
			} else {
				disasm = rz_str_dup(name);
			}
			break;
		case 2:
			if (len > 1) {
				if (arg1 == A_OFFSET) {
					disasm = rz_str_newf(name, (unsigned int)arg_offset(pc, pc + 2, buf[1]));
				} else if (arg1 == A_ADDR11) {
					disasm = rz_str_newf(name, (unsigned int)arg_addr11(pc, pc + 2, buf));
				} else if ((arg1 == A_RI) || (arg1 == A_RN)) {
					// op @Ri, arg; op Rn, arg
					if (arg2 == A_OFFSET) {
						disasm = rz_str_newf(name, buf[0] & mask, (unsigned int)arg_offset(pc, pc + 2, buf[1]));
					} else {
						disasm = rz_str_newf(name, buf[0] & mask, buf[1]);
					}
					val2 = buf[1];
				} else if ((arg2 == A_RI) || (arg2 == A_RN)) {
					// op arg, @Ri; op arg, Rn
					disasm = rz_str_newf(name, buf[1], buf[0] & mask);
					val1 = buf[1];
				} else if (arg1 == A_BIT) {
					// bit addressing mode
					disasm = rz_str_newf(name, arg_bit(buf[1]), buf[1] & 0x07);
					val1 = buf[1];
				} else {
					// direct, immediate, bit
					disasm = rz_str_newf(name, buf[1]);
					val1 = buf[1];
				}
			} else {
				*olen = -1;
				return rz_str_dup("truncated");
			}
			break;
		case 3:
			if (len > 2) {
				if (arg1 == A_ADDR16) {
					disasm = rz_str_newf(name, (unsigned int)apply_bank(pc, 0x100 * buf[1] + buf[2]));
				} else if (arg1 == A_IMM16) {
					disasm = rz_str_newf(name, 0x100 * buf[1] + buf[2]);
				} else if (arg2 == A_OFFSET) {
					if (mask != A_NONE) {
						// @Ri, immediate, offset; Rn, immediate, offset
						disasm = rz_str_newf(name, buf[0] & mask, buf[1], (unsigned int)arg_offset(pc, pc + 3, buf[1]));
					} else if (arg1 == A_BIT) {
						// bit, offset
						disasm = rz_str_newf(name, arg_bit(buf[1]), buf[1] & 0x07, (unsigned int)arg_offset(pc, pc + 3, buf[2]));
						val1 = buf[1];
					} else {
						// direct, offset; a, immediate, offset
						disasm = rz_str_newf(name, buf[1], (unsigned int)arg_offset(pc, pc + 3, buf[2]));
						val1 = buf[1];
					}
				} else if (arg3 == A_OFFSET) {
					// @Ri/Rn, direct, offset
					disasm = rz_str_newf(name, buf[0] & mask, buf[1], (unsigned int)arg_offset(pc, pc + 3, buf[2]));
					val2 = buf[1];
				} else if (arg1 == A_DIRECT && arg2 == A_DIRECT) {
					// op direct, direct has src and dest swapped
					disasm = rz_str_newf(name, buf[2], buf[1]);
					val1 = buf[2];
					val2 = buf[1];
				} else {
					// direct, immediate
					disasm = rz_str_newf(name, buf[1], buf[2]);
					val1 = buf[1];
				}
			} else {
				*olen = -1;
				return rz_str_dup("truncated");
			}
			break;
		default:
			// if we get here something is wrong
			return 0;
		}

		// substitute direct addresses with register name
		*olen = oplen;
		if (disasm) {
			disasm = _replace_register(disasm, arg1, val1);
			disasm = _replace_register(disasm, arg2, val2);
			return disasm;
		}
		return NULL;
	}

	// invalid op-code
	return 0;
}
