开始写riscv指令解析

2025-04-16 19:39:04 +08:00
parent 19ea8f8184
commit 719ece9555
2 changed files with 509 additions and 0 deletions
--- a/cpu/riscv.c
+++ b/cpu/riscv.c
@@ -0,0 +1,500 @@
+
+#include "riscv.h"
+
+
+
+
+
+/*
+
+每个指令长度为32bit，分为6个类型
+|--------------+------------+-----------+-------------+--------------+---------------|
+|  [31-25]     |  [24-20]   |  [19-15]  |  [14-12]    |  [11-7]      |     [6-0]     |
+|--------------+------------+-----------+-------------+--------------+---------------|
+|    funct7    |     rs2    |    rs1    |   funct3    |     rd       |     opcode    | R-type 计算指令
+|--------------+------------+-----------+-------------+--------------+---------------|
+|         imm[11:0]         |    rs1    |   funct3    |     rd       |     opcode    | I-type 加载指令
+|--------------+------------+-----------+-------------+--------------+---------------|
+|   imm[11:5]  |     rs2    |    rs1    |   funct3    | imm[4:0]     |     opcode    | S-type 存储指令
+|--------------+------------+-----------+-------------+--------------+---------------|
+|imm[12] [10:5]|     rs2    |    rs1    |   funct3    | imm[4:1][11] |     opcode    | B-type 分支指令
+|--------------+------------+-----------+-------------+--------------+---------------|
+|                      imm[31:12]                     |     rd       |     opcode    | U-type 立即数指令
+|-----------------------------------------------------+--------------+---------------|
+|            imm[20] [10:1] [11] [19:12]              |     rd       |     opcode    | J-type 跳转指令
+|-----------------------------------------------------+--------------+---------------|
+
+*/
+
+// 定义opcode
+#define opcode_lui   0x37  // U-type
+#define opcode_auipc 0x17  // U-type
+#define opcode_jal   0x6f  // J-type
+#define opcode_jalr  0x67  // I-type
+
+// B-type
+#define opcode_beq  0x63
+#define opcode_bne  0x63
+#define opcode_blt  0x63
+#define opcode_bge  0x63
+#define opcode_bltu 0x63
+#define opcode_bgeu 0x63
+
+// I-type
+#define opcode_lb   0x03
+#define opcode_lh   0x03
+#define opcode_lw   0x03
+#define opcode_lbu  0x03
+#define opcode_lhu  0x03
+
+// S-type
+#define opcode_sb   0x23
+#define opcode_sh   0x23
+#define opcode_sw   0x23
+
+// I-type
+#define opcode_addi 0x13
+#define opcode_slti 0x13
+#define opcode_sltiu 0x13
+#define opcode_xori 0x13
+#define opcode_ori  0x13
+#define opcode_andi 0x13
+#define opcode_slli 0x13
+#define opcode_srli 0x13
+#define opcode_srai 0x13
+
+// R-type
+#define opcode_add  0x33
+#define opcode_sub  0x33
+#define opcode_sll  0x33
+#define opcode_slt  0x33
+#define opcode_sltu 0x33
+#define opcode_xor  0x33
+#define opcode_srl  0x33
+#define opcode_sra  0x33
+#define opcode_or   0x33
+#define opcode_and  0x33
+
+#define opcode_fence 0x0f
+#define opcode_fence_i 0x0f
+
+// 系统调用
+#define opcode_ecall 0x73
+#define opcode_ebreak 0x73
+#define opcode_csrrw 0x73
+#define opcode_csrrs 0x73
+#define opcode_csrrc 0x73
+#define opcode_csrrwi 0x73
+#define opcode_csrrsi 0x73
+#define opcode_csrrci 0x73
+
+
+#define MEM_SIZE 1024*1024
+#define MEM_ADDR_BASE 0x100000000
+
+#define zero reg[0]
+#define ra   reg[1]
+#define sp   reg[2]
+#define gp   reg[3]
+#define tp   reg[4]
+#define t0   reg[5]
+#define t1   reg[6]
+#define t2   reg[7]
+#define s0   reg[8]
+#define s1   reg[9]
+#define a0   reg[10]
+#define a1   reg[11]
+#define a2   reg[12]
+#define a3   reg[13]
+#define a4   reg[14]
+#define a5   reg[15]
+#define a6   reg[16]
+#define a7   reg[17]
+#define s2   reg[18]
+#define s3   reg[19]
+#define s4   reg[20]
+#define s5   reg[21]
+#define s6   reg[22]
+#define s7   reg[23]
+#define s8   reg[24]
+#define s9   reg[25]
+#define s10  reg[26]
+#define s11  reg[27]
+#define t3   reg[28]
+#define t4   reg[29]
+#define t5   reg[30]
+#define t6   reg[31]
+
+#define fp   reg[8]
+
+typedef struct {
+  uint32_t mem[MEM_SIZE];
+  uint32_t* rom;
+  uint32_t rom_size;
+  uint32_t rom_addr_base;
+  uint32_t pc;
+  uint32_t reg[32];
+  uint32_t csrs[4096];
+}riscv_t;
+
+#define mem_wr(addr) riscv->mem[(addr-MEM_ADDR_BASE) >> 2]
+#define mem_wrb(addr) ((uint8_t *)riscv->mem)[(addr-MEM_ADDR_BASE)]
+#define mem_wrh(addr) ((uint16_t *)riscv->mem)[(addr-MEM_ADDR_BASE) >> 1]
+void ins_add(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] + riscv->reg[rs2];
+}
+
+void ins_addi(riscv_t* riscv, int rs1, int imm, int rd) {
+  if (imm & (1 << 11)) {
+    imm |= 0xfffff800;
+  }
+  riscv->reg[rd] = riscv->reg[rs1] + imm;
+}
+
+void ins_addiw(riscv_t* riscv, int rs1, int imm, int rd) {
+  if (imm & (1 << 11)) {
+    imm |= 0xfffff800;
+  }
+  riscv->reg[rd] = riscv->reg[rs1] + imm;
+}
+
+void ins_addw(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] + riscv->reg[rs2];
+}
+
+void ins_and(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] & riscv->reg[rs2];
+}
+
+void ins_andi(riscv_t* riscv, int rs1, int imm, int rd) {
+  if (imm & (1 << 11)) {
+    imm |= 0xfffff800;
+  }
+  riscv->reg[rd] = riscv->reg[rs1] & imm;
+}
+
+// 设置pc指针高位地址
+void ins_auipc(riscv_t* riscv, int imm, int rd) {
+  riscv->reg[rd] = riscv->pc + imm;
+}
+
+void ins_beq(riscv_t* riscv, int rs2, int rs1, int imm) {
+  if (riscv->reg[rs1] == riscv->reg[rs2]) {
+    riscv->pc += imm;
+  }
+}
+
+void ins_bge(riscv_t* riscv, int rs2, int rs1, int imm) {
+  if ((int)riscv->reg[rs1] >= (int)riscv->reg[rs2]) {
+    riscv->pc += imm;
+  }
+}
+
+void ins_bgeu(riscv_t* riscv, int rs2, int rs1, int imm) {
+  if (riscv->reg[rs1] >= riscv->reg[rs2]) {
+    riscv->pc += imm;
+  }
+}
+
+void ins_blt(riscv_t* riscv, int rs2, int rs1, int imm) {
+  if ((int)riscv->reg[rs1] < (int)riscv->reg[rs2]) {
+    riscv->pc += imm;
+  }
+}
+
+void ins_bltu(riscv_t* riscv, int rs2, int rs1, int imm) {
+  if (riscv->reg[rs1] < riscv->reg[rs2]) {
+    riscv->pc += imm;
+  }
+}
+
+void ins_bne(riscv_t* riscv, int rs2, int rs1, int imm) {
+  if (riscv->reg[rs1] != riscv->reg[rs2]) {
+    riscv->pc += imm;
+  }
+}
+
+// 读后清除
+void ins_csrrc(riscv_t* riscv, int rs1, int rd, int csr) {
+  uint32_t t = riscv->csrs[csr];
+  riscv->csrs[csr] = riscv->csrs[csr] & ~riscv->reg[rs1];
+  riscv->reg[rd] = t;
+}
+
+void ins_csrrs(riscv_t* riscv, int rs1, int rd, int csr) {
+  uint32_t t = riscv->csrs[csr];
+  riscv->csrs[csr] = riscv->csrs[csr] | riscv->reg[rs1];
+  riscv->reg[rd] = t;
+}
+
+void ins_csrrw(riscv_t* riscv, int rs1, int rd, int csr) {
+  uint32_t t = riscv->csrs[csr];
+  riscv->csrs[csr] = riscv->reg[rs1];
+  riscv->reg[rd] = t;
+}
+
+void ins_csrrci(riscv_t* riscv, int imm, int rd, int csr) {
+  uint32_t t = riscv->csrs[csr];
+  riscv->csrs[csr] = riscv->csrs[csr] & ~imm;
+  riscv->reg[rd] = t;
+}
+
+void ins_csrrsi(riscv_t* riscv, int imm, int rd, int csr) {
+  uint32_t t = riscv->csrs[csr];
+  riscv->csrs[csr] = riscv->csrs[csr] | imm;
+  riscv->reg[rd] = t;
+}
+
+void ins_csrrwi(riscv_t* riscv, int imm, int rd, int csr) {
+  uint32_t t = riscv->csrs[csr];
+  riscv->csrs[csr] = imm;
+  riscv->reg[rd] = t;
+}
+
+void ins_ecall(riscv_t* riscv) {
+  printf("ecall\n");
+}
+
+void ins_ebreak(riscv_t* riscv) {
+  printf("ebreak\n");
+}
+
+void ins_jal(riscv_t* riscv, int imm, int rd) {
+  riscv->reg[rd] = riscv->pc + 4;
+  riscv->pc += imm;
+}
+
+void ins_jalr(riscv_t* riscv, int rs1, int imm, int rd) {
+  uint32_t t;
+  t = riscv->pc + 4;
+  riscv->pc = (riscv->reg[rs1] + imm) & (~1);
+  riscv->reg[rd] = t;
+}
+
+void ins_lb(riscv_t* riscv, int rs1, int imm, int rd) {
+  uint32_t addr = riscv->reg[rs1] + imm;
+  riscv->reg[rd] = (int)mem_wrb(addr);
+}
+
+void ins_lbu(riscv_t* riscv, int rs1, int imm, int rd) {
+  uint32_t addr = riscv->reg[rs1] + imm;
+  riscv->reg[rd] = mem_wrb(addr);
+}
+
+void ins_lh(riscv_t* riscv, int rs1, int imm, int rd) {
+  uint32_t addr = riscv->reg[rs1] + imm;
+  riscv->reg[rd] = (int)mem_wrh(addr);
+}
+
+void ins_lhu(riscv_t* riscv, int rs1, int imm, int rd) {
+  uint32_t addr = riscv->reg[rs1] + imm;
+  riscv->reg[rd] = mem_wrh(addr);
+}
+
+void ins_lw(riscv_t* riscv, int rs1, int imm, int rd) {
+  uint32_t addr = riscv->reg[rs1] + imm;
+  riscv->reg[rd] = mem_wr(addr);
+}
+
+void ins_lwu(riscv_t* riscv, int rs1, int imm, int rd) {
+  uint32_t addr = riscv->reg[rs1] + imm;
+  riscv->reg[rd] = mem_wr(addr);
+}
+
+void ins_lui(riscv_t* riscv, int imm, int rd) {
+  riscv->reg[rd] = imm;
+}
+
+void ins_mret(riscv_t* riscv) {
+  riscv->pc = riscv->csrs[0x305];
+  printf("mret\n");
+}
+
+void ins_or(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] | riscv->reg[rs2];
+}
+
+void ins_ori(riscv_t* riscv, int rs1, int imm, int rd) {
+  if (imm & (1 << 11)) {
+    imm |= 0xfffff800;
+  }
+  riscv->reg[rd] = riscv->reg[rs1] | imm;
+}
+
+void ins_sb(riscv_t* riscv, int rs2, int rs1, int imm) {
+  uint32_t addr = riscv->reg[rs1] + imm;
+  mem_wrb(addr) = riscv->reg[rs2];
+}
+
+void ins_sh(riscv_t* riscv, int rs2, int rs1, int imm) {
+  uint32_t addr = riscv->reg[rs1] + imm;
+  mem_wrh(addr) = riscv->reg[rs2];
+}
+
+void ins_sw(riscv_t* riscv, int rs2, int rs1, int imm) {
+  uint32_t addr = riscv->reg[rs1] + imm;
+  mem_wr(addr) = riscv->reg[rs2];
+}
+
+void ins_sll(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] << riscv->reg[rs2];
+}
+
+void ins_slli(riscv_t* riscv, int rs1, int imm, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] << imm;
+}
+
+void ins_slliw(riscv_t* riscv, int rs1, int imm, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] << imm;
+}
+
+void ins_sllw(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] << riscv->reg[rs2];
+}
+
+void ins_slt(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = (int)riscv->reg[rs1] < (int)riscv->reg[rs2];
+}
+
+void ins_slti(riscv_t* riscv, int rs1, int imm, int rd) {
+  if (imm & (1 << 11)) {
+    imm |= 0xfffff800;
+  }
+  riscv->reg[rd] = (int)riscv->reg[rs1] < imm;
+}
+
+void ins_sltiu(riscv_t* riscv, int rs1, int imm, int rd) {
+  if (imm & (1 << 11)) {
+    imm |= 0xfffff800;
+  }
+  riscv->reg[rd] = riscv->reg[rs1] < (uint32_t)imm;
+}
+
+void ins_sltu(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] < riscv->reg[rs2];
+}
+
+void ins_sra(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = (int)riscv->reg[rs1] >> riscv->reg[rs2];
+}
+
+void ins_srai(riscv_t* riscv, int rs1, int imm, int rd) {
+  riscv->reg[rd] = (int)riscv->reg[rs1] >> imm;
+}
+
+void ins_sraiw(riscv_t* riscv, int rs1, int imm, int rd) {
+  riscv->reg[rd] = (int)riscv->reg[rs1] >> imm;
+}
+
+void ins_sraw(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = (int)riscv->reg[rs1] >> riscv->reg[rs2];
+}
+
+void ins_srl(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] >> riscv->reg[rs2];
+}
+
+void ins_srli(riscv_t* riscv, int rs1, int imm, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] >> imm;
+}
+
+void ins_srliw(riscv_t* riscv, int rs1, int imm, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] >> imm;
+}
+
+void ins_srlw(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] >> riscv->reg[rs2];
+}
+
+void ins_sub(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] - riscv->reg[rs2];
+}
+
+void ins_subw(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] - riscv->reg[rs2];
+}
+
+void ins_wfi(riscv_t* riscv) {
+  printf("wfi\n");
+}
+
+void ins_xor(riscv_t* riscv, int rs2, int rs1, int rd) {
+  riscv->reg[rd] = riscv->reg[rs1] ^ riscv->reg[rs2];
+}
+
+void ins_xori(riscv_t* riscv, int rs1, int imm, int rd) {
+  if (imm & (1 << 11)) {
+    imm |= 0xfffff800;
+  }
+  riscv->reg[rd] = riscv->reg[rs1] ^ imm;
+}
+
+
+#define imm_u_type(_ins,_imm) {\
+    _imm = (_ins >> 12) << 12;\
+  }
+
+#define imm_j_type(_ins,_imm) {\
+    _imm = ((_ins >> 21) & 0x3ff) << 1;\
+    _imm |= ((_ins >> 20) & 1) << 11;\
+    _imm |= ((_ins >> 12) & 0xff) << 12;\
+    _imm |= ((_ins >> 31) & 1) << 20;\
+  }
+
+#define imm_i_type(_ins,_imm) {\
+    _imm = (_ins >> 20) & 0xfff;\
+  }
+
+#define imm_b_type(_ins,_imm) {\
+    _imm = ((_ins >> 31) & 1) << 12;\
+    _imm |= ((_ins >> 7) & 0x1) << 11;\
+    _imm |= ((_ins >> 8) & 0xf) << 1;\
+    _imm |= ((_ins >> 25) & 0x1f) << 5;\
+  }
+
+#define imm_s_type(_ins,_imm) {\
+    _imm = ((_ins >> 7) & 0x1f);\
+    _imm |= (_ins >> 25) << 5;\
+  }
+
+
+// 解析指令
+int riscv_decode(riscv_t* riscv, uint32_t ins) {
+  int imm = 0;
+  int rs1 = (ins >> 15) & 0x1f;
+  int rs2 = (ins >> 20) & 0x1f;
+  int rd = (ins >> 7) & 0x1f;
+  int funct3 = (ins >> 12) & 0x7;
+  int funct7 = (ins >> 25) & 0x7f;
+  int opcode = ins & 0x7f;
+  switch (opcode) {
+    // U-type
+  case opcode_lui:
+    imm_u_type(ins, imm);
+    ins_lui(riscv, imm, rd);
+    break;
+  case opcode_auipc:
+    imm_u_type(ins, imm);
+    ins_auipc(riscv, imm, rd);
+    break;
+    // J-type
+  case opcode_jal:
+    imm_j_type(ins, imm);
+    ins_jal(riscv, imm, rd);
+    break;
+  case opcode_jalr:
+    // I-type
+    imm_i_type(ins, imm);
+    ins_jalr(riscv, rs1, imm, rd);
+    break;
+  case opcode_beq:
+
+  }
+}
+
+int riscv_init(riscv_t* riscv, uint32_t* rom, uint32_t rom_addr_base, uint32_t rom_size) {
+  riscv->rom = rom;
+  riscv->rom_size = rom_size;
+  riscv->rom_addr_base = rom_addr_base;
+  riscv->pc = 0;
+}
--- a/cpu/riscv.h
+++ b/cpu/riscv.h
@@ -0,0 +1,9 @@
+
+#ifndef riscv_h__
+#define riscv_h__
+
+#include "stdint.h"
+
+
+
+#endif