diff --git a/main.c b/main.c index fcd8f46..4c4b160 100644 --- a/main.c +++ b/main.c @@ -1,107 +1,81 @@ #include -#include -#include + +typedef uint8_t u8; +typedef uint16_t u16; +typedef uint32_t u32; + +typedef int8_t i8; +typedef int16_t i16; +typedef int32_t i32; typedef struct{ - uint32_t regs[32], pc; - uint8_t* mem; + u32 regs[32], pc; + u8* mem; }Cpu; -const uint32_t MEM_OFFSET = 0x80000000; +const u32 MEM_OFFSET = 0x80000000; -static inline uint8_t load8(const uint8_t* mem, const uint32_t addr){ +static inline u8 load8(const u8* mem, const u32 addr){ return mem[addr - MEM_OFFSET]; } -static inline uint16_t load16(const uint8_t* mem, const uint32_t addr){ - return *(uint16_t*)(mem + addr - MEM_OFFSET); +static inline u16 load16(const u8* mem, const u32 addr){ + return *(u16*)(mem + addr - MEM_OFFSET); } -static inline uint32_t load32(const uint8_t* mem, const uint32_t addr){ - return *(uint32_t*)(mem + addr - MEM_OFFSET); +static inline u32 load32(const u8* mem, const u32 addr){ + return *(u32*)(mem + addr - MEM_OFFSET); } -static inline void store8(uint8_t* mem, const uint32_t addr, const uint8_t val){ +static inline void store8(u8* mem, const u32 addr, const u8 val){ mem[addr - MEM_OFFSET] = val; } -static inline void store16(uint8_t* mem, const uint32_t addr, - const uint16_t val){ - - *(uint16_t*)(mem + addr - MEM_OFFSET) = val; +static inline void store16(u8* mem, const u32 addr, const u16 val){ + *(u16*)(mem + addr - MEM_OFFSET) = val; } -static inline void store32(uint8_t* mem, const uint32_t addr, - const uint32_t val){ - - *(uint32_t*)(mem + addr - MEM_OFFSET) = val; +static inline void store32(u8* mem, const u32 addr, const u32 val){ + *(u32*)(mem + addr - MEM_OFFSET) = val; } -void jump(uint32_t* pc, const uint32_t addr){ - if(addr % 4 != 0){ - fprintf(stderr, "EXCEPTION: instruction-address-misaligned\n"); - exit(1); - } - - *pc = addr; -} - -void B_type(uint32_t* pc, const uint8_t func3, const uint32_t regs[32], - const uint8_t rs1, const uint8_t rs2, const int16_t imm){ - - *pc -= 4; +void B_type(u32* pc, const u8 func3, const u32 regs[32], const u8 rs1, + const u8 rs2, const i16 imm){ switch(func3){ - case /*BEQ*/ 0x0: - if(regs[rs1] == regs[rs2]) jump(pc, *pc + (int32_t)imm); - break; - - case /*BNE*/ 0x1: - if(regs[rs1] != regs[rs2]) jump(pc, *pc + (int32_t)imm); - break; - + case /*BEQ*/ 0x0: if(regs[rs1] == regs[rs2]) *pc += (i32)imm - 4; break; + case /*BNE*/ 0x1: if(regs[rs1] != regs[rs2]) *pc += (i32)imm - 4; break; case /*BLT*/ 0x4: - if((int32_t)regs[rs1] < (int32_t)regs[rs2]){ - jump(pc, *pc + (int32_t)imm); - } + if((i32)regs[rs1] < (i32)regs[rs2]) *pc += (i32)imm - 4; break; - case /*BGE*/ 0x5: - if((int32_t)regs[rs1] >= (int32_t)regs[rs2]){ - jump(pc, *pc + (int32_t)imm); - } + case /*BGE*/ 0x5: + if((i32)regs[rs1] >= (i32)regs[rs2]) *pc += (i32)imm - 4; break; - case /*BLTU*/ 0x6: - if(regs[rs1] < regs[rs2]) jump(pc, *pc + (int32_t)imm); - break; - - case /*BGEU*/ 0x7: if(regs[rs1] >= regs[rs2]) - jump(pc, *pc + (int32_t)imm); - break; - - default: *pc += 4; break; + case /*BLTU*/ 0x6: if(regs[rs1] < regs[rs2]) *pc += (i32)imm - 4; break; + case /*BGEU*/ 0x7: if(regs[rs1] >= regs[rs2]) *pc += (i32)imm - 4; break; } } -void L_type(const uint8_t* mem, const uint8_t func3, uint32_t regs[32], - const uint8_t rd, const uint8_t rs1, const int16_t imm){ +void L_type(const u8* mem, const u8 func3, u32 regs[32], const u8 rd, + const u8 rs1, const i16 imm){ - const uint32_t addr = regs[rs1] + (int32_t)imm; + const u32 addr = regs[rs1] + (i32)imm; switch(func3){ - case /*LB*/ 0x0: regs[rd] = (int32_t)(int8_t)load8(mem, addr); break; - case /*LH*/ 0x1: regs[rd] = (int32_t)(int16_t)load16(mem, addr); break; + case /*LB*/ 0x0: regs[rd] = (i32)(i8)load8(mem, addr); break; + case /*LH*/ 0x1: regs[rd] = (i32)(i16)load16(mem, addr); break; case /*LW*/ 0x2: regs[rd] = load32(mem, addr); break; case /*LBU*/ 0x4: regs[rd] = load8(mem, addr); break; case /*LHU*/ 0x5: regs[rd] = load16(mem, addr); break; } } -void S_type(uint8_t* mem, const uint8_t func3, const uint32_t regs[32], - const uint8_t rs1, const uint8_t rs2, const int16_t imm){ +void S_type(u8* mem, const u8 func3, const u32 regs[32], const u8 rs1, + const u8 rs2, const i16 imm){ - const uint32_t addr = regs[rs1] + (int32_t)imm; + const u32 addr = regs[rs1] + (i32)imm; switch(func3){ case /*SB*/ 0x0: store8(mem, addr, regs[rs2]); break; @@ -110,26 +84,26 @@ void S_type(uint8_t* mem, const uint8_t func3, const uint32_t regs[32], } } -void I_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, const int16_t imm){ +void I_type(const u8 func3, const u8 func7, u32 regs[32], const u8 rd, + const u8 rs1, const u8 rs2, const i16 imm){ switch(func3){ - case /*ADDI*/ 0x0: regs[rd] = regs[rs1] + (int32_t)imm; break; - case /*SLTI*/ 0x2: regs[rd] = (int32_t)regs[rs1] < (int32_t)imm; break; - case /*SLTIU*/ 0x3: regs[rd] = regs[rs1] < (uint32_t)(int32_t)imm; break; - case /*XORI*/ 0x4: regs[rd] = regs[rs1] ^ (int32_t)imm; break; - case /*ORI*/ 0x6: regs[rd] = regs[rs1] | (int32_t)imm; break; - case /*ANDI*/ 0x7: regs[rd] = regs[rs1] & (int32_t)imm; break; + case /*ADDI*/ 0x0: regs[rd] = regs[rs1] + (i32)imm; break; + case /*SLTI*/ 0x2: regs[rd] = (i32)regs[rs1] < (i32)imm; break; + case /*SLTIU*/ 0x3: regs[rd] = regs[rs1] < (u32)(i32)imm; break; + case /*XORI*/ 0x4: regs[rd] = regs[rs1] ^ (i32)imm; break; + case /*ORI*/ 0x6: regs[rd] = regs[rs1] | (i32)imm; break; + case /*ANDI*/ 0x7: regs[rd] = regs[rs1] & (i32)imm; break; case /*SLLI*/ 0x1: regs[rd] = regs[rs1] << rs2; break; case /*SRLI/SRAI*/ 0x5: if(func7 == /*SRLI*/ 0x00) regs[rd] = regs[rs1] >> rs2; - else if(func7 == /*SRAI*/ 0x20) regs[rd] = (int32_t)regs[rs1] >> rs2; + else if(func7 == /*SRAI*/ 0x20) regs[rd] = (i32)regs[rs1] >> rs2; break; } } -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){ +void R_type(const u8 func3, const u8 func7, u32 regs[32], const u8 rd, + const u8 rs1, const u8 rs2){ switch(func3){ case /*ADD/SUB*/ 0x0: @@ -138,14 +112,14 @@ void R_type(const uint8_t func3, const uint8_t func7, uint32_t regs[32], break; case /*SLL*/ 0x1: regs[rd] = regs[rs1] << (regs[rs2] & 0x1f); break; - case /*SLT*/ 0x2: regs[rd] = (int32_t)regs[rs1] < (int32_t)regs[rs2]; break; + case /*SLT*/ 0x2: regs[rd] = (i32)regs[rs1] < (i32)regs[rs2]; break; case /*SLTU*/ 0x3: regs[rd] = regs[rs1] < regs[rs2]; break; case /*XOR*/ 0x4: regs[rd] = regs[rs1] ^ regs[rs2]; break; case /*SRL/SRA*/ 0x5: if(func7 == /*SRL*/ 0x00) regs[rd] = regs[rs1] >> (regs[rs2] & 0x1f); else if(func7 == /*SRA*/ 0x20){ - regs[rd] = (int32_t)regs[rs1] >> (regs[rs2] & 0x1f); + regs[rd] = (i32)regs[rs1] >> (regs[rs2] & 0x1f); } break; @@ -156,23 +130,23 @@ void R_type(const uint8_t func3, const uint8_t func7, uint32_t regs[32], void step(Cpu* cpu){ //fetch - const uint32_t inst = load32(cpu->mem, cpu->pc); + const u32 inst = load32(cpu->mem, cpu->pc); cpu->pc += 4; //decode #define opcode (inst & 0x7f) - #define func3 (inst >> 12 & 0x7) - #define func7 (inst >> 25 & 0x7f) - #define rd (inst >> 7 & 0x1f) - #define rs1 (inst >> 15 & 0x1f) - #define rs2 (inst >> 20 & 0x1f) - #define imm_I ((int32_t)inst >> 20) - #define imm_S (imm_I & 0xffffffe0 | rd) + #define func3 (inst >> 12 & 0x7) + #define func7 (inst >> 25 & 0x7f) + #define rd (inst >> 7 & 0x1f) + #define rs1 (inst >> 15 & 0x1f) + #define rs2 (inst >> 20 & 0x1f) + #define imm_I ((i32)inst >> 20) + #define imm_S (imm_I & 0xffffffe0 | rd) - #define imm_B (((int32_t)(inst & 0x80000000) >> 19) | \ + #define imm_B (((i32)(inst & 0x80000000) >> 19) | \ ((inst & 0x80) << 4) | (inst >> 20 & 0x7e0) | (inst >> 7 & 0x1e)) - #define imm_J (((int32_t)(inst & 0x80000000) >> 11) | (inst & 0xff000) | \ + #define imm_J (((i32)(inst & 0x80000000) >> 11) | (inst & 0xff000) | \ (inst >> 9 & 0x800) | (inst >> 20 & 0x7fe)) //execute @@ -181,14 +155,11 @@ void step(Cpu* cpu){ switch(opcode){ case /*LUI*/ 0x37: cpu->regs[rd] = inst & 0xfffff000; break; case /*AUIPC*/ 0x17: cpu->regs[rd] = cpu->pc + (inst & 0xfffff000); break; - case /*JAL*/ 0x6f: - cpu->regs[rd] = cpu->pc; jump(&cpu->pc, cpu->pc + imm_J - 4); - break; - + case /*JAL*/ 0x6f: cpu->regs[rd] = cpu->pc; cpu->pc += imm_J - 4; break; case /*JALR*/ 0x67: - const uint32_t pc_copy = cpu->pc; - jump(&cpu->pc, (cpu->regs[rs1] + (int32_t)imm_I) & 0xfffffffe); - cpu->regs[rd] = pc_copy; + const u32 last_pc = cpu->pc; + cpu->pc = (cpu->regs[rs1] + (i32)imm_I) & 0xfffffffe; + cpu->regs[rd] = last_pc; break; case 0x63: B_type(&cpu->pc, func3, cpu->regs, rs1, rs2, imm_B); break;