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This commit is contained in:
inixyz
2023-10-08 21:14:09 +03:00
parent 505e51a75e
commit 3d9d3efa1c
1 changed files with 51 additions and 8 deletions
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59
main.c
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@@ -1,4 +1,6 @@
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
typedef struct{
uint32_t regs[32], pc;
@@ -35,24 +37,49 @@ static inline void store32(uint8_t* mem, const uint32_t addr,
*(uint32_t*)(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;
switch(func3){
case /*BEQ*/ 0x0: if(regs[rs1] == regs[rs2]) *pc += (int32_t)imm; break;
case /*BNE*/ 0x1: if(regs[rs1] != regs[rs2]) *pc += (int32_t)imm; break;
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 /*BLT*/ 0x4:
if((int32_t)regs[rs1] < (int32_t)regs[rs2]) *pc += (int32_t)imm;
if((int32_t)regs[rs1] < (int32_t)regs[rs2]){
jump(pc, *pc + (int32_t)imm);
}
break;
case /*BGE*/ 0x5:
if((int32_t)regs[rs1] >= (int32_t)regs[rs2]) *pc += (int32_t)imm;
if((int32_t)regs[rs1] >= (int32_t)regs[rs2]){
jump(pc, *pc + (int32_t)imm);
}
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;
case /*BLTU*/ 0x6: if(regs[rs1] < regs[rs2]) *pc += (int32_t)imm; break;
case /*BGEU*/ 0x7: if(regs[rs1] >= regs[rs2]) *pc += (int32_t)imm; break;
default: *pc += 4; break;
}
}
@@ -141,13 +168,29 @@ void step(Cpu* cpu){
#define rs2 (inst >> 20 & 0x1f)
#define imm_I ((int32_t)inst >> 20)
#define imm_S (imm_I & 0xffffffe0 | rd)
#define imm_B ((int32_t)inst >> 31 << 12 | (inst & 0x80 << 4) | \
(inst >> 20 & 0x7e0) | (inst >> 7 & 0x1e))
#define imm_B (((int32_t)(inst & 0x80000000) >> 19) | \
((inst & 0x80) << 4) | (inst >> 20 & 0x7e0) | (inst >> 7 & 0x1e))
#define imm_J (((int32_t)(inst & 0x80000000) >> 11) | (inst & 0xff000) | \
(inst >> 9 & 0x800) | (inst >> 20 & 0x7fe))
//execute
cpu->regs[0] = 0;
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 /*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;
break;
case 0x63: B_type(&cpu->pc, func3, cpu->regs, rs1, rs2, imm_B); break;
case 0x03: L_type(cpu->mem, func3, cpu->regs, rd, rs1, imm_I); break;
case 0x23: S_type(cpu->mem, func3, cpu->regs, rs1, rs2, imm_S); break;