diff options
Diffstat (limited to 'input_bin.c')
| -rw-r--r-- | input_bin.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/input_bin.c b/input_bin.c new file mode 100644 index 0000000..54a99f3 --- /dev/null +++ b/input_bin.c @@ -0,0 +1,173 @@ +#include <stdio.h> +#include <stdint.h> +#include <stdlib.h> +#include <errno.h> + +#include "parse.h" + +static void disasm_rtype(uint16_t i, uint16_t unused, struct instruction *inst) +{ + inst->type = INST_TYPE_R; + inst->inst.r.oper = GET_OPER(i); + inst->inst.r.dest = GET_REG_DEST(i); + inst->inst.r.left = GET_REG_LEFT(i); + inst->inst.r.right = GET_REG_RIGHT(i); +} + +static void disasm_nitype(uint16_t i, uint16_t unused, struct instruction *inst) +{ + inst->type = INST_TYPE_NI; + inst->inst.i.oper = GET_OPER(i); + inst->inst.i.dest = GET_REG_DEST(i); + inst->inst.i.left = GET_REG_LEFT(i); + inst->inst.i.imm.value = GET_NI_IMM(i); + inst->inst.i.imm_is_ident = 0; +} + +static void disasm_witype(uint16_t i, uint16_t imm, struct instruction *inst) +{ + inst->type = INST_TYPE_WI; + inst->inst.i.oper = GET_OPER(i); + inst->inst.i.dest = GET_REG_DEST(i); + inst->inst.i.left = GET_REG_LEFT(i); + inst->inst.i.imm.value = imm; + inst->inst.i.imm_is_ident = 0; +} + +static void disasm_jreg(uint16_t i, uint16_t unused, struct instruction *inst) +{ + inst->type = INST_TYPE_JR; + inst->inst.jr.cond = GET_JB_COND(i); + inst->inst.jr.reg = GET_JUMP_REG(i); +} + +static void disasm_jimm(uint16_t i, uint16_t imm, struct instruction *inst) +{ + inst->type = INST_TYPE_JI; + inst->inst.ji.cond= GET_JB_COND(i); + inst->inst.ji.imm.value = imm; + inst->inst.ji.imm_is_ident = 0; +} + +static void disasm_bimm(uint16_t i, uint16_t pc, struct instruction *inst) +{ + struct { signed int s:10; } sign; + int offset = sign.s = GET_B_OFFSET(i); + inst->type = INST_TYPE_B; + inst->inst.b.cond = GET_JB_COND(i); + inst->inst.b.imm.value = pc + 2 * offset; + inst->inst.b.imm_is_ident = 0; +} + + +/** + * FIXME move and factor out with parse.c */ +static struct instruction *insts = NULL; +static size_t insts_count = 0; +static int add_instruction(struct instruction inst) +{ + struct instruction *old_insts = insts; + insts = realloc(insts, (insts_count + 1) * sizeof(struct instruction)); + if (!insts) { + free(old_insts); + perror("realloc"); + return 1; + } + + insts[insts_count] = inst; + + insts_count++; + return 0; +} + + + +/* FIXME needs whatsit arguments. f, tok, tok length */ +static int disasm_file(FILE *f) +{ + int ret = 0; + size_t offs = 0; + uint16_t inst = 0; + uint8_t c[2] = { 0 }; + size_t extra_read = 0; + uint16_t extra_arg = 0; + struct instruction i = { 0 }; + void (*disasm_inst)(uint16_t, uint16_t, struct instruction*); + + 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; + } + disasm_inst(inst, extra_arg, &i); + if (ret < 0) { + fprintf(stderr, "Error handling instruction at byte %zd\n", offs); + break; + } + if (add_instruction(i)) + return 1; + offs += sizeof(c) + extra_read; + } + if (!feof(f)) { + perror("fread"); + ret = -errno; + } + return ret; +} + +int disasm(FILE *f, struct instruction **i, size_t *i_count) +{ + int ret = 0; + + ret = disasm_file(f); + *i = insts; + *i_count = insts_count; + + return ret; +} |