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- #include "insn.h"
-
- #include <stddef.h>
- #include <stdio.h>
-
- #include "cpu.h"
- #include "log.h"
-
- #define TABLE_SIZE 0x34
-
- #define BITS(x, start, len) (((x) >> (start)) & ((1 << (len)) - 1))
-
- #define OP(insn) BITS(insn, 26, 6)
- #define RS(insn) BITS(insn, 21, 5)
- #define RT(insn) BITS(insn, 16, 5)
- #define RD(insn) BITS(insn, 11, 5)
- #define COMMENT(insn) BITS(insn, 6, 20)
- #define IMM5(insn) BITS(insn, 6, 5)
- #define OP2(insn) BITS(insn, 0, 6)
- #define IMM(insn) BITS(insn, 0, 16)
-
- static cpu_insn_handler primary_insn_handler[TABLE_SIZE];
- static cpu_insn_handler secondary_insn_handler[TABLE_SIZE];
-
- void insn_execute(cpu_t *cpu, uint32_t insn) {
- const op_primary_t op = OP(insn);
-
- if (op == SPECIAL) {
- const op_secondary_t op2 = OP2(insn);
-
- if (op2 > TABLE_SIZE || secondary_insn_handler[op2] == NULL) {
- fatal("Unsupported instruction: insn=%08x, op=%02x, op2=%02x", insn,
- op, op2);
- }
-
- secondary_insn_handler[op2](cpu, insn);
- return;
- }
-
- if (op > TABLE_SIZE || primary_insn_handler[op] == NULL) {
- fatal("Unsupported instruction: insn=%08x, op=%02x", insn, op);
- }
-
- primary_insn_handler[op](cpu, insn);
- }
-
- void insn_lw(cpu_t *cpu, uint32_t insn) {
- const uint8_t rt = RT(insn);
- const uint8_t rs = RS(insn);
- const uint16_t imm = IMM(insn);
-
- debug("LW %s, [%s + %x]", REG_NAMES[rt], REG_NAMES[rs], imm);
- cpu->regs[rt] = cpu_read32(cpu, cpu->regs[rs] + imm);
- }
-
- void insn_srl(cpu_t *cpu, uint32_t insn) {
- const uint8_t rd = RD(insn);
- const uint8_t rt = RT(insn);
- const uint8_t imm5 = IMM5(insn);
-
- debug("SRL %s, %s, %u", REG_NAMES[rd], REG_NAMES[rt], imm5);
- cpu->regs[rd] = cpu->regs[rt] >> imm5;
- }
-
- void insn_addu(cpu_t *cpu, uint32_t insn) {
- const uint8_t rd = RD(insn);
- const uint8_t rs = RS(insn);
- const uint8_t rt = RT(insn);
-
- debug("ADDU %s, %s, %s", REG_NAMES[rd], REG_NAMES[rs], REG_NAMES[rt]);
- cpu->regs[rd] = cpu->regs[rs] + cpu->regs[rt];
- }
-
- void insn_addiu(cpu_t *cpu, uint32_t insn) {
- const uint8_t rt = RT(insn);
- const uint8_t rs = RS(insn);
- const int16_t imm = (int16_t)IMM(insn);
-
- debug("ADDIU %s, %s, %x", REG_NAMES[rt], REG_NAMES[rs], imm);
- cpu->regs[rt] = cpu->regs[rs] + imm;
- }
-
- static cpu_insn_handler primary_insn_handler[TABLE_SIZE] = {
- [LW] = insn_lw,
- [ADDIU] = insn_addiu,
- };
-
- static cpu_insn_handler secondary_insn_handler[TABLE_SIZE] = {
- [ADDU] = insn_addu,
- [SRL] = insn_srl,
- };
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