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62 lines
1.4 KiB
62 lines
1.4 KiB
#include "insn.h"
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#include "cpu.h"
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#include "util.h"
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#include <stddef.h>
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#include <stdio.h>
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#define TABLE_SIZE 0x34
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void insn_lw(cpu_t *cpu, uint32_t insn);
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static cpu_insn_handler primary_insn_handler[TABLE_SIZE] = {
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[LW] = insn_lw,
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};
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static cpu_insn_handler secondary_insn_handler[TABLE_SIZE] = {NULL};
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#define BITS(x, start, len) (((x) >> (start)) & ((1 << (len)) - 1))
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#define OP(insn) BITS(insn, 26, 6)
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#define RS(insn) BITS(insn, 21, 5)
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#define RT(insn) BITS(insn, 16, 5)
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#define RD(insn) BITS(insn, 11, 5)
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#define COMMENT(insn) BITS(insn, 6, 20)
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#define IMM5(insn) BITS(insn, 6, 5)
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#define OP2(insn) BITS(insn, 0, 6)
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#define IMM(insn) BITS(insn, 0, 16)
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void insn_execute(cpu_t *cpu, uint32_t insn)
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{
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const op_primary_t op = OP(insn);
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if (op == SPECIAL)
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{
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const op_secondary_t op2 = OP2(insn);
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if (op2 > TABLE_SIZE || secondary_insn_handler[op2] == NULL)
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{
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fatal("unsupported instruction: insn=%08x, op=%02x, op2=%02x", insn,
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op, op2);
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}
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secondary_insn_handler[op2](cpu, insn);
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}
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if (op > TABLE_SIZE || primary_insn_handler[op] == NULL)
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{
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fatal("unsupported instruction: insn=%08x, op=%02x", insn, op);
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}
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primary_insn_handler[op](cpu, insn);
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}
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void insn_lw(cpu_t *cpu, uint32_t insn)
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{
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const uint8_t rs = RS(insn);
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const uint8_t rt = RT(insn);
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const uint16_t imm = IMM(insn);
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printf("LW R%u, [R%u + %x]\n", rt, rs, imm);
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cpu->regs[rt] = cpu_read32(cpu, cpu->regs[rs] + imm);
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}
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