diff options
| author | Steven Le Rouzic <steven.lerouzic@gmail.com> | 2024-05-13 00:04:44 +0200 |
|---|---|---|
| committer | Steven Le Rouzic <steven.lerouzic@gmail.com> | 2024-05-13 00:04:44 +0200 |
| commit | f95a85de0082010e4af83e26e99299d601bb48d6 (patch) | |
| tree | 0b70ff8fa990ceeb18c2522ea80f2599d50ebae4 /emulator/instruction.h | |
| parent | f9541157b62ec44deff0b906757c223ca0220102 (diff) | |
Some work on CSR
Diffstat (limited to 'emulator/instruction.h')
| -rw-r--r-- | emulator/instruction.h | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/emulator/instruction.h b/emulator/instruction.h new file mode 100644 index 0000000..97c9fe9 --- /dev/null +++ b/emulator/instruction.h @@ -0,0 +1,80 @@ +#pragma once
+
+#include <stdint.h>
+
+#include "emulator/bits.h"
+
+struct Instruction
+{
+ uint8_t opcode;
+ uint8_t rs1;
+ uint8_t rs2;
+ uint8_t rd;
+ uint8_t funct3;
+ uint8_t funct7;
+ uint32_t imm;
+};
+typedef struct Instruction Instruction;
+
+static Instruction decode_r_type(uint32_t word)
+{
+ Instruction instruction = {0};
+ instruction.opcode = word & 0x7F;
+ instruction.rd = (word >> 7) & 0x1F;
+ instruction.funct3 = (word >> 12) & 0x07;
+ instruction.rs1 = (word >> 15) & 0x1F;
+ instruction.rs2 = (word >> 20) & 0x1F;
+ instruction.funct7 = word >> 25;
+ return instruction;
+};
+
+static Instruction decode_i_type(uint32_t word)
+{
+ Instruction instruction = {0};
+ instruction.opcode = word & 0x7F;
+ instruction.rd = (word >> 7) & 0x1F;
+ instruction.funct3 = (word >> 12) & 0x07;
+ instruction.rs1 = (word >> 15) & 0x1F;
+ instruction.imm = sign_extend(word >> 20, 12);
+ return instruction;
+};
+
+static Instruction decode_s_type(uint32_t word)
+{
+ Instruction instruction = {0};
+ instruction.opcode = word & 0x7F;
+ instruction.funct3 = (word >> 12) & 0x07;
+ instruction.rs1 = (word >> 15) & 0x1F;
+ instruction.rs2 = (word >> 20) & 0x1F;
+ instruction.imm = sign_extend(((word >> 7) & 0x1F) | (word >> 25), 12);
+ return instruction;
+};
+
+static Instruction decode_b_type(uint32_t word)
+{
+ Instruction instruction = decode_s_type(word);
+ instruction.imm = ((instruction.imm << 11) & 0x800) | (instruction.imm & 0xfffff7ff);
+ return instruction;
+};
+
+static Instruction decode_u_type(uint32_t word)
+{
+ Instruction instruction = {0};
+ instruction.opcode = word & 0x7F;
+ instruction.rd = (word >> 7) & 0x1F;
+ instruction.imm = word & 0xFFFFF000;
+ return instruction;
+};
+
+static Instruction decode_j_type(uint32_t word)
+{
+ Instruction instruction = {0};
+ instruction.opcode = word & 0x7F;
+ instruction.rd = (word >> 7) & 0x1F;
+ instruction.imm = sign_extend(
+ ((word & 0x80000000) >> 11) |
+ ((word & 0x000FF000) >> 0) |
+ ((word & 0x00100000) >> 9) |
+ ((word & 0x7FE00000) >> 20), 21);
+ return instruction;
+}
|