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refactor for speed

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This commit is contained in:
inixyz
2023-10-08 14:27:13 +03:00
parent 5d288ba726
commit b9ab9c301d
1 changed files with 49 additions and 16 deletions
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65
main.c
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@@ -5,19 +5,48 @@ typedef struct{
uint8_t* mem;
}Cpu;
const uint32_t MEMORY_OFFSET = 0x80000000;
const uint32_t MEM_OFFSET = 0x80000000;
static inline uint8_t load8(const uint8_t* memory, const uint32_t addr){
return memory[addr - MEM_OFFSET];
}
static inline uint16_t load16(const uint8_t* memory, const uint32_t addr){
return *(uint16_t*)(memory + addr - MEM_OFFSET);
}
static inline uint32_t load32(const uint8_t* memory, const uint32_t addr){
return *(uint32_t*)(memory + addr - MEMORY_OFFSET);
return *(uint32_t*)(memory + addr - MEM_OFFSET);
}
static inline uint32_t select_bits(const uint32_t val, const uint8_t end,
const uint8_t start){
const uint8_t len = end - start + 1;
return val >> start & (1 << len - 1);
static inline uint8_t decode_opcode(const uint32_t inst){
return inst & 0x7f;
}
static inline uint8_t decode_func3(const uint32_t inst){
return inst >> 12 & 0x7;
}
static inline uint8_t decode_func7(const uint32_t inst){
return inst >> 25 & 0x7f;
}
static inline uint8_t decode_rd(const uint32_t inst){
return inst >> 7 & 0x1f;
}
static inline uint8_t decode_rs1(const uint32_t inst){
return inst >> 15 & 0x1f;
}
static inline uint8_t decode_rs2(const uint32_t inst){
return inst >> 20 & 0x1f;
}
// static inline int16_t decode_imm_I(const uint32_t inst){
// }
void R_type(const uint8_t func3, const uint8_t func7, uint32_t regs[32],
const uint8_t rd, const uint8_t rs1, const uint8_t rs2){
@@ -42,25 +71,29 @@ void R_type(const uint8_t func3, const uint8_t func7, uint32_t regs[32],
}
}
// void L_type(){
// switch(func3){
// case /*LB*/ 0x0: regs[rd] = (int32_t)(int8_t)load8(mem, regs[rs1] + ) break;
// }
// }
void step(Cpu* cpu){
//instruction fetch
const uint32_t inst = load32(cpu->mem, cpu->pc);
cpu->pc += 4;
//instruction decoding
#define opcode select_bits(inst, 6, 0)
#define func3 select_bits(inst, 14, 12)
#define func7 select_bits(inst, 31, 25)
#define rd select_bits(inst, 11, 7)
#define rs1 select_bits(inst, 19, 15)
#define rs2 select_bits(inst, 24, 20)
#define opcode decode_opcode(inst)
#define func3 decode_func3(inst)
#define func7 decode_func7(inst)
#define rd decode_rd(inst)
#define rs1 decode_rs1(inst)
#define rs2 decode_rs2(inst)
//execute
switch(opcode){
case /*R-type*/ 0x33: R_type(func3, func7, cpu->regs, rd, rs1, rs2); break;
//case /*I-type*/ 0x03: I_type(); break;
//case /*S-type*/ 0x23: S_type(); break;
//case /*B-type*/ 0x63: B_type(); break;
}
}