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#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <errno.h>
#include "util.h"
void print_help(const char *argv0)
{
fprintf(stderr, "Syntax: %s <in.bin>\0 <out.asm>\n", argv0);
}
int disasm_rtype(uint16_t i, uint16_t unused)
{
const char *oper = get_asm_from_oper(GET_OPER(i));
const char *dest = get_asm_from_reg(GET_REG_DEST(i));
const char *left = get_asm_from_reg(GET_REG_LEFT(i));
const char *right = get_asm_from_reg(GET_REG_RIGHT(i));
/* FIXME add special cases:
* - nop
* - neg
* - mv
*/
printf("%s %s, %s, %s\n", oper, dest, left, right);
return 0;
}
int disasm_nitype(uint16_t i, uint16_t unused)
{
const char *oper = get_asm_from_oper(GET_OPER(i));
const char *dest = get_asm_from_reg(GET_REG_DEST(i));
const char *left = get_asm_from_reg(GET_REG_LEFT(i));
uint16_t imm = GET_NI_IMM(i);
/** FIXME add special cases:
* - ldi
*/
/* FIXME review sign around immediate value */
printf("%si %s, %s, 0x%x\n", oper, dest, left, imm);
return 0;
}
int disasm_witype(uint16_t i, uint16_t unused)
{
const char *oper = get_asm_from_oper(GET_OPER(i));
const char *dest = get_asm_from_reg(GET_REG_DEST(i));
const char *left = get_asm_from_reg(GET_REG_LEFT(i));
uint16_t imm = GET_NI_IMM(i);
/* FIXME handle wide imm value */
printf("%si, %s, %s, 0x%x\n", "oper", dest, left, "?");
return 0;
}
int disasm_jreg(uint16_t i, uint16_t unused)
{
const char *inst = get_asm_from_j(GET_JB_COND(i));
const char *reg = get_asm_from_reg(GET_JUMP_REG(i));
printf("%s %s\n", inst, reg);
return 0;
}
int disasm_bimm(uint16_t i, uint16_t pc)
{
const char *inst = get_asm_from_b(GET_JB_COND(i));
struct {signed int s:10;} sign;
int offset = sign.s = GET_B_OFFSET(i);
printf("%s 0x%x\n", inst, pc + 2 * offset);
return 0;
}
int disasm_jimm(uint16_t i, uint16_t imm)
{
const char *inst = get_asm_from_j(GET_JB_COND(i));
printf("%s 0x%x\n", inst, imm);
return 0;
}
int disasm(FILE *f)
{
int ret = 0;
size_t offs = 0;
size_t extra_read = 0;
uint16_t inst = 0;
uint16_t extra_arg = 0;
uint8_t c[2] = { 0 };
int (*disasm_inst)(uint16_t, uint16_t);
while (!feof(f) && fread(c, sizeof(c), 1, f) == 1) {
extra_read = 0;
inst = c[0] << 8 | c[1];
switch (GET_INST_TYPE(inst)) {
case INST_TYPE_RTYPE:
disasm_inst = disasm_rtype;
break;
case INST_TYPE_NITYPE:
disasm_inst = disasm_nitype;
break;
case INST_TYPE_WITYPE:
if (fread(c, sizeof(c), 1, f) != 1) {
ret = -errno;
break;
}
extra_read = sizeof(c);
extra_arg = c[0] << 16 | c[1];
disasm_inst = disasm_witype;
break;
case INST_TYPE_JTYPE:
/* J Type can be split into three further subtypes:
* - branch (always immediate, 2 bytes)
* - jump reg (2 bytes)
* - jump immediate (4 bytes)
*/
if (inst & MASK_IS_BRANCH) {
disasm_inst = disasm_bimm;
extra_arg = offs;
} else {
if (inst & MASK_JR) {
disasm_inst = disasm_jreg;
} else {
if (fread(c, sizeof(c), 1, f) != 1) {
ret = -errno;
break;
}
extra_arg = c[0] << 16 | c[1];
extra_read = sizeof(c);
disasm_inst = disasm_jimm;
}
}
break;
default:
printf("Unhandled instruction at byte %zd\n", offs);
ret = -1;
break;
}
/* Fall out of loop if picking a handler errored */
if (ret) {
break;
}
printf("%04x:\t", offs);
ret = disasm_inst(inst, extra_arg);
if (ret < 0) {
fprintf(stderr, "Error handling instruction at byte %zd\n", offs);
break;
}
offs += sizeof(c) + extra_read;
}
if (!feof(f)) {
perror("fread");
ret = errno;
} else {
/* print out final, empty label */
printf("%04x:\n", offs);
}
return ret;
}
int main(int argc, char **argv)
{
int ret = 0;
FILE *fin = NULL;
if (argc < 2) {
print_help(argv[0]);
return 1;
}
if (!(fin = fopen(argv[1], "rb"))) {
perror("fopen");
return 1;
}
ret = disasm(fin);
fclose(fin);
return ret;
}
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