// SPDX-FileCopyrightText: 2019 v3l0c1r4pt0r <v3l0c1r4pt0r@gmail.com>
// SPDX-License-Identifier: LGPL-3.0-only

#include <rz_asm.h>
#include <rz_lib.h>
#include <or1k/or1k_disas.h>

static int insn_to_str(RzAsm *a, char **line, insn_t *descr, insn_extra_t *extra, ut32 insn) {
	struct operands o = { 0 };
	char *name;
	insn_type_t type = type_of_opcode(descr, extra);
	insn_type_descr_t *type_descr = &types[INSN_X];

	/* only use type descriptor if it has some useful data */
	if (has_type_descriptor(type) && is_type_descriptor_defined(type)) {
		type_descr = &types[type];
	}

	o.rd = get_operand_value(insn, type_descr, INSN_OPER_D);
	o.ra = get_operand_value(insn, type_descr, INSN_OPER_A);
	o.rb = get_operand_value(insn, type_descr, INSN_OPER_B);
	o.k1 = get_operand_value(insn, type_descr, INSN_OPER_K1);
	o.k2 = get_operand_value(insn, type_descr, INSN_OPER_K2);
	o.n = get_operand_value(insn, type_descr, INSN_OPER_N);
	o.k = get_operand_value(insn, type_descr, INSN_OPER_K);
	o.i = get_operand_value(insn, type_descr, INSN_OPER_I);
	o.l = get_operand_value(insn, type_descr, INSN_OPER_L);

	name = extra ? extra->name : descr->name;

	if (!name || !type_descr->format) {
		/* this should not happen, give up */
		return 4;
	}

	switch (type) {
	case INSN_X:
		*line = rz_str_newf(type_descr->format, name);
		break;
	case INSN_N:
		*line = rz_str_newf(type_descr->format, name,
			(sign_extend(o.n, get_operand_mask(type_descr, INSN_OPER_N)) << 2) +
				a->pc);
		break;
	case INSN_K:
		*line = rz_str_newf(type_descr->format, name, o.k);
		break;
	case INSN_DK:
		*line = rz_str_newf(type_descr->format, name, o.rd, o.k);
		break;
	case INSN_DN:
		*line = rz_str_newf(type_descr->format, name, o.rd, o.n << 13);
		break;
	case INSN_B:
		*line = rz_str_newf(type_descr->format, name, o.rb);
		break;
	case INSN_D:
		*line = rz_str_newf(type_descr->format, name, o.rd);
		break;
	case INSN_AI:
		*line = rz_str_newf(type_descr->format, name, o.ra, o.i);
		break;
	case INSN_DAI:
		*line = rz_str_newf(type_descr->format, name, o.rd, o.ra, o.i);
		break;
	case INSN_DAK:
		*line = rz_str_newf(type_descr->format, name, o.rd, o.ra, o.i);
		break;
	case INSN_DAL:
		*line = rz_str_newf(type_descr->format, name, o.rd, o.ra, o.l);
		break;
	case INSN_DA:
		*line = rz_str_newf(type_descr->format, name, o.rd, o.ra);
		break;
	case INSN_DAB:
		*line = rz_str_newf(type_descr->format, name, o.rd, o.ra, o.rb);
		break;
	case INSN_AB:
		*line = rz_str_newf(type_descr->format, name, o.ra, o.rb);
		break;
	case INSN_IABI:
		*line = rz_str_newf(type_descr->format, name,
			o.ra, o.rb, (o.k1 << 11) | o.k2);
		break;
	case INSN_KABK:
		*line = rz_str_newf(type_descr->format, name,
			o.ra, o.rb, (o.k1 << 11) | o.k2);
		break;
	default:
		break;
	}
	return 4;
}

static int or1k_disassemble(RzAsm *a, RzAsmOp *op, const ut8 *buf, int len) {
	ut32 insn, opcode;
	ut8 opcode_idx;
	char *line = NULL;
	insn_t *insn_descr;
	insn_extra_t *extra_descr;

	op->size = -1;

	if (len < 4) {
		rz_asm_op_set_asm(op, "invalid");
		return op->size;
	}

	/* read instruction and basic opcode value */
	insn = rz_read_be32(buf);
	op->size = 4;
	opcode = (insn & INSN_OPCODE_MASK);
	opcode_idx = opcode >> INSN_OPCODE_SHIFT;

	/* make sure instruction descriptor table is not overflowed */
	if (opcode_idx >= insns_count) {
		rz_asm_op_set_asm(op, "invalid");
		return op->size;
	}

	/* if instruction is marked as invalid finish processing now */
	insn_descr = &or1k_insns[opcode_idx];
	if (insn_descr->type == INSN_INVAL) {
		rz_asm_op_set_asm(op, "invalid");
		return op->size;
	}

	/* if name is null, but extra is present, it means 6 most significant bits
	 * are not enough to decode instruction */
	if (!insn_descr->name && insn_descr->extra) {
		if ((extra_descr = find_extra_descriptor(insn_descr->extra, insn)) != NULL) {
			insn_to_str(a, &line, insn_descr, extra_descr, insn);
		}
	} else {
		/* otherwise basic descriptor is enough */
		insn_to_str(a, &line, insn_descr, NULL, insn);
	}
	if (line) {
		rz_asm_op_set_asm(op, line);
		free(line);
	} else {
		rz_asm_op_set_asm(op, "invalid");
	}
	return op->size;
}

RzAsmPlugin rz_asm_plugin_or1k = {
	.name = "or1k",
	.desc = "OpenRISC 1000 disassembler",
	.license = "LGPL3",
	.arch = "or1k",
	.bits = 32,
	.endian = RZ_SYS_ENDIAN_BIG,
	.disassemble = &or1k_disassemble,
};

#ifndef RZ_PLUGIN_INCORE
RZ_API RzLibStruct rizin_plugin = {
	.type = RZ_LIB_TYPE_ASM, .data = &rz_asm_plugin_or1k, .version = RZ_VERSION
};
#endif
