diff options
Diffstat (limited to 'emulator')
| -rw-r--r-- | emulator/elf.c | 133 | ||||
| -rw-r--r-- | emulator/elf.h | 6 | ||||
| -rw-r--r-- | emulator/hart.c | 446 | ||||
| -rw-r--r-- | emulator/hart.h | 16 | ||||
| -rw-r--r-- | emulator/hart_test.c | 251 | ||||
| -rw-r--r-- | emulator/main.c | 817 |
6 files changed, 860 insertions, 809 deletions
diff --git a/emulator/elf.c b/emulator/elf.c new file mode 100644 index 0000000..43409cc --- /dev/null +++ b/emulator/elf.c @@ -0,0 +1,133 @@ +#include <stdint.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+#include <assert.h>
+
+#define ET_NONE 0x00
+#define ET_REL 0x01
+#define ET_EXEC 0x02
+#define ET_DYN 0x03
+#define ET_CORE 0x04
+
+struct Elf32Header
+{
+ uint8_t ident[16];
+ uint16_t type;
+ uint16_t machine;
+ uint32_t version;
+ uint32_t entry;
+ uint32_t phoff;
+ uint32_t shoff;
+ uint32_t flags;
+ uint16_t ehsize;
+ uint16_t phentsize;
+ uint16_t phnum;
+ uint16_t shentsize;
+ uint16_t shnum;
+ uint16_t shstrndx;
+};
+
+#define PT_NULL 0x00000000
+#define PT_LOAD 0x00000001
+#define PT_DYNAMIC 0x00000002
+#define PT_INTERP 0x00000003
+#define PT_NOTE 0x00000004
+#define PT_SHLIB 0x00000005
+#define PT_PHDR 0x00000006
+#define PT_TLS 0x00000007
+
+#define PF_X 0x1
+#define PF_W 0x2
+#define PF_R 0x4
+
+struct Elf32ProgramHeader
+{
+ uint32_t type;
+ uint32_t offset;
+ uint32_t vaddr;
+ uint32_t paddr;
+ uint32_t filesz;
+ uint32_t memsz;
+ uint32_t flags;
+ uint32_t align;
+};
+
+bool load_elf(const char* file, char* mem, uint32_t mem_size, uint32_t* start_address)
+{
+ FILE* fp = fopen(file, "rb");
+ if (fp == NULL)
+ {
+ printf("Couldn't open input file\n");
+ return false;
+ }
+
+ struct Elf32Header header;
+ size_t read = fread(&header, sizeof(struct Elf32Header), 1, fp);
+ if (read != 1)
+ {
+ printf("ELF header too small\n");
+ return false;
+ }
+
+ static uint8_t kValidIdent[7] = {
+ 0x7f, 0x45, 0x4c, 0x46,
+ 1, 1, 1
+ };
+ if (memcmp(kValidIdent, header.ident, 7) != 0)
+ {
+ printf("Invalid ELF header\n");
+ return false;
+ }
+
+ if (header.type != ET_EXEC)
+ {
+ printf("Can only link EXEC ELF files\n");
+ return false;
+ }
+
+ memset(mem, 0, mem_size);
+
+ assert(header.phnum == 0 || header.phentsize == sizeof(struct Elf32ProgramHeader));
+ for (uint32_t i = 0; i < header.phnum; ++i)
+ {
+ struct Elf32ProgramHeader pheader;
+
+ fseek(fp, header.phoff + i * header.phentsize, SEEK_SET);
+ read = fread(&pheader, sizeof(struct Elf32ProgramHeader), 1, fp);
+ if (read != 1)
+ {
+ printf("Error reading program header at index %u\n", i);
+ return false;
+ }
+
+ if (pheader.type == PT_LOAD)
+ {
+ if (pheader.paddr + pheader.memsz > mem_size)
+ {
+ printf("Memory not large enough for ELF file\n");
+ return false;
+ }
+
+ fseek(fp, pheader.offset, SEEK_SET);
+ read = fread(mem + pheader.paddr, pheader.filesz, 1, fp);
+ if (read != 1)
+ {
+ printf("Error when copying ELF segment\n");
+ return false;
+ }
+ }
+ }
+
+ if (header.entry > mem_size)
+ {
+ printf("Entry address out of bounds\n");
+ return false;
+ }
+
+ *start_address = header.entry;
+ fclose(fp);
+
+ return true;
+}
diff --git a/emulator/elf.h b/emulator/elf.h new file mode 100644 index 0000000..2ba3739 --- /dev/null +++ b/emulator/elf.h @@ -0,0 +1,6 @@ +#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+
+bool load_elf(const char* file, char* mem, uint32_t mem_size, uint32_t* start_address);
diff --git a/emulator/hart.c b/emulator/hart.c new file mode 100644 index 0000000..cfca837 --- /dev/null +++ b/emulator/hart.c @@ -0,0 +1,446 @@ +#include "emulator/hart.h"
+
+#include <stdio.h>
+#include <inttypes.h>
+#include <assert.h>
+#include <stdbool.h>
+#include <string.h>
+
+static inline uint32_t sign_extend(uint32_t word, uint32_t size)
+{
+ const uint32_t mask = 1U << (size - 1);
+ return (word ^ mask) - mask;
+}
+
+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;
+}
+
+static void execute_op_imm(Hart* hart, uint32_t instruction)
+{
+ const Instruction inst = decode_i_type(instruction);
+ if (inst.rd == 0) return;
+
+ switch (inst.funct3)
+ {
+ case 0: // ADDI
+ hart->regs[inst.rd] = hart->regs[inst.rs1] + inst.imm;
+ break;
+ case 1: // SLLI
+ hart->regs[inst.rd] = hart->regs[inst.rs1] << (inst.imm & 0x1F);
+ break;
+ case 2: // SLTI
+ hart->regs[inst.rd] = (int32_t)hart->regs[inst.rs1] < (int32_t)inst.imm ? 1 : 0;
+ break;
+ case 3: // SLTIU
+ hart->regs[inst.rd] = hart->regs[inst.rs1] < inst.imm ? 1 : 0;
+ break;
+ case 4: // XORI
+ hart->regs[inst.rd] = hart->regs[inst.rs1] ^ inst.imm;
+ break;
+ case 5: // SRLI, SRAI
+ {
+ const uint32_t shamt = inst.imm & 0x1F;
+ uint32_t res = hart->regs[inst.rs1] >> shamt;
+ if ((inst.imm & 0x400) && shamt > 0) { res = sign_extend(res, 32 - shamt); }
+ hart->regs[inst.rd] = res;
+ break;
+ }
+ case 6: // ORI
+ hart->regs[inst.rd] = hart->regs[inst.rs1] | inst.imm;
+ break;
+ case 7: // ANDI
+ hart->regs[inst.rd] = hart->regs[inst.rs1] & inst.imm;
+ break;
+ default:
+ assert(!"Unhandled OP-IMM");
+ }
+}
+
+static void execute_op(Hart* hart, uint32_t instruction)
+{
+ const Instruction inst = decode_r_type(instruction);
+ if (inst.rd == 0) return;
+
+ switch (inst.funct3)
+ {
+ case 0: // ADD, SUB
+ if (instruction & 0x40000000)
+ {
+ hart->regs[inst.rd] = hart->regs[inst.rs1] - hart->regs[inst.rs2];
+ }
+ else
+ {
+ hart->regs[inst.rd] = hart->regs[inst.rs1] + hart->regs[inst.rs2];
+ }
+ break;
+ case 1: // SLL
+ hart->regs[inst.rd] = hart->regs[inst.rs1] << (hart->regs[inst.rs2] & 0x1F);
+ break;
+ case 2: // SLT
+ hart->regs[inst.rd] = (int32_t)hart->regs[inst.rs1] < (int32_t)hart->regs[inst.rs2] ? 1 : 0;
+ break;
+ case 3: // SLTU
+ hart->regs[inst.rd] = hart->regs[inst.rs1] < hart->regs[inst.rs2] ? 1 : 0;
+ break;
+ case 4: // XOR
+ hart->regs[inst.rd] = hart->regs[inst.rs1] ^ hart->regs[inst.rs2];
+ break;
+ case 5: // SRL, SRA
+ {
+ const uint32_t shamt = hart->regs[inst.rs2] & 0x1F;
+ uint32_t res = hart->regs[inst.rs1] >> shamt;
+ if ((instruction & 0x40000000) && shamt > 0) { res = sign_extend(res, 32 - shamt); }
+ hart->regs[inst.rd] = res;
+ break;
+ }
+ case 6: // OR
+ hart->regs[inst.rd] = hart->regs[inst.rs1] | hart->regs[inst.rs2];
+ break;
+ case 7: // AND
+ hart->regs[inst.rd] = hart->regs[inst.rs1] & hart->regs[inst.rs2];
+ break;
+ default:
+ assert(!"Unhandled OP-IMM");
+ }
+}
+
+static void execute_branch(Hart* hart, uint32_t instruction)
+{
+ const Instruction inst = decode_b_type(instruction);
+ const uint32_t r1 = hart->regs[inst.rs1];
+ const uint32_t r2 = hart->regs[inst.rs2];
+ bool take_branch = false;
+
+ switch (inst.funct3)
+ {
+ case 0: take_branch = (r1 == r2); break;
+ case 1: take_branch = (r1 != r2); break;
+ case 4: take_branch = (r1 < r2); break;
+ case 5: take_branch = (r1 >= r2); break;
+ case 6: take_branch = ((int32_t)r1 < (int32_t)r2); break;
+ case 7: take_branch = ((int32_t)r1 >= (int32_t)r2); break;
+ }
+
+ if (take_branch)
+ {
+ hart->pc += inst.imm;
+ }
+ else
+ {
+ hart->pc += 4;
+ }
+}
+
+static inline uint32_t load_size(Hart* hart, uint32_t address, uint32_t size)
+{
+ if ((address & 0x80000000) == 0)
+ {
+ assert(address + size < hart->mem_size);
+ uint32_t value = 0;
+ memcpy(&value, hart->mem + address, size);
+ return value;
+ }
+
+ return 0;
+}
+
+static uint32_t load_byte(Hart* hart, uint32_t address)
+{
+ return load_size(hart, address, 1);
+}
+
+static uint32_t load_half(Hart* hart, uint32_t address)
+{
+ return load_size(hart, address, 2);
+}
+
+static uint32_t load_word(Hart* hart, uint32_t address)
+{
+ return load_size(hart, address, 4);
+}
+
+static inline void store_size(Hart* hart, uint32_t address, uint32_t value, uint32_t size)
+{
+ if ((address & 0x80000000) == 0)
+ {
+ assert(address + size < hart->mem_size);
+ memcpy(hart->mem + address, &value, size);
+ }
+ else if (address == 0x80000000)
+ {
+ fwrite(&value, 1, size, stdout);
+ }
+}
+
+static void store_byte(Hart* hart, uint32_t address, uint8_t value)
+{
+ store_size(hart, address, value, 1);
+}
+
+static void store_half(Hart* hart, uint32_t address, uint16_t value)
+{
+ store_size(hart, address, value, 2);
+}
+
+static void store_word(Hart* hart, uint32_t address, uint32_t value)
+{
+ store_size(hart, address, value, 4);
+}
+
+static void execute_op_load(Hart* hart, uint32_t instruction)
+{
+ const Instruction inst = decode_i_type(instruction);
+ const uint32_t address = hart->regs[inst.rs1] + inst.imm;
+
+ uint32_t value = 0;
+
+ switch (inst.funct3 & 0x03)
+ {
+ case 0:
+ value = load_byte(hart, address);
+ if ((inst.funct3 & 0x40) == 0)
+ {
+ value = sign_extend(value, 8);
+ }
+ break;
+ case 1:
+ value = load_half(hart, address);
+ if ((inst.funct3 & 0x40) == 0)
+ {
+ value = sign_extend(value, 16);
+ }
+ break;
+ case 2:
+ value = load_byte(hart, address);
+ break;
+ default:
+ assert(!"Unhandled load size");
+ break;
+ }
+
+ if (inst.rd != 0)
+ {
+ hart->regs[inst.rd] = value;
+ }
+}
+
+static void execute_op_store(Hart* hart, uint32_t instruction)
+{
+ const Instruction inst = decode_s_type(instruction);
+ const uint32_t address = hart->regs[inst.rs1] + inst.imm;
+ const uint32_t value = hart->regs[inst.rs2];
+
+ switch (inst.funct3 & 0x03)
+ {
+ case 0: store_byte(hart, address, value & 0xFF); break;
+ case 1: store_half(hart, address, value & 0xFFFF); break;
+ case 2: store_word(hart, address, value); break;
+ default:
+ assert(!"Unhandled store size");
+ break;
+ }
+}
+
+static void execute_misc_mem(Hart* hart, uint32_t instruction)
+{
+ const Instruction inst = decode_i_type(instruction);
+
+ if (inst.funct3 == 0)
+ {
+ // FENCE
+ }
+ else
+ {
+ assert(!"Unhandled MISC-MEM instruction");
+ }
+}
+
+static void execute_system(Hart* hart, uint32_t instruction)
+{
+ const Instruction inst = decode_i_type(instruction);
+
+ if (inst.funct3 == 0 && inst.rs1 == 0 && inst.rd == 0)
+ {
+ if (inst.imm == 0)
+ {
+ // ECALL
+ }
+ else if (inst.imm == 1)
+ {
+ // EBREAK
+ }
+ else
+ {
+ assert(!"Unhandled SYSTEM/PRIV instruction");
+ }
+ }
+ else
+ {
+ assert(!"Unhandled SYSTEM instruction");
+ }
+}
+
+void execute(Hart* hart, uint32_t instruction)
+{
+ switch (instruction & 0x7f)
+ {
+ case 0x03:
+ execute_op_load(hart, instruction);
+ hart->pc += 4;
+ break;
+ case 0x0F:
+ execute_misc_mem(hart, instruction);
+ hart->pc += 4;
+ break;
+ case 0x13:
+ execute_op_imm(hart, instruction);
+ hart->pc += 4;
+ break;
+ case 0x17: // AUIPC
+ {
+ Instruction inst = decode_u_type(instruction);
+ if (inst.rd != 0)
+ {
+ hart->regs[inst.rd] = inst.imm + hart->pc;
+ }
+ hart->pc += 4;
+ break;
+ }
+ case 0x23:
+ execute_op_store(hart, instruction);
+ hart->pc += 4;
+ break;
+ case 0x33:
+ execute_op(hart, instruction);
+ hart->pc += 4;
+ break;
+ case 0x37: // LUI
+ {
+ Instruction inst = decode_u_type(instruction);
+ if (inst.rd != 0)
+ {
+ hart->regs[inst.rd] = inst.imm;
+ }
+ hart->pc += 4;
+ break;
+ }
+ case 0x63:
+ execute_branch(hart, instruction);
+ break;
+ case 0x67: // JALR
+ {
+ Instruction inst = decode_i_type(instruction);
+ assert(inst.funct3 == 0);
+ if (inst.rd != 0)
+ {
+ hart->regs[inst.rd] = hart->pc + 4;
+ }
+ hart->pc = (hart->regs[inst.rs1] + inst.imm) & 0xFFFFFFFE;
+ break;
+ }
+ case 0x6F: // JAL
+ {
+ Instruction inst = decode_j_type(instruction);
+ if (inst.rd != 0)
+ {
+ hart->regs[inst.rd] = hart->pc + 4;
+ }
+ hart->pc += inst.imm;
+ break;
+ }
+ case 0x73:
+ {
+ execute_system(hart, instruction);
+ hart->pc += 4;
+ break;
+ }
+ default:
+ assert(!"Unhandled opcode");
+ }
+
+ assert(hart->regs[0] == 0);
+}
+
+void execute_from(Hart* hart, uint32_t start_address)
+{
+ hart->pc = start_address;
+
+ while (true)
+ {
+ uint32_t instruction = load_word(hart, hart->pc);
+ execute(hart, instruction);
+ }
+}
+
diff --git a/emulator/hart.h b/emulator/hart.h new file mode 100644 index 0000000..5e9d451 --- /dev/null +++ b/emulator/hart.h @@ -0,0 +1,16 @@ +#pragma once
+
+#include <stdint.h>
+
+struct Hart
+{
+ uint32_t pc;
+ uint32_t regs[32];
+ char* mem;
+ uint32_t mem_size;
+};
+typedef struct Hart Hart;
+
+void execute(Hart* hart, uint32_t instruction);
+void execute_from(Hart* hart, uint32_t start_address);
+
diff --git a/emulator/hart_test.c b/emulator/hart_test.c new file mode 100644 index 0000000..5509dab --- /dev/null +++ b/emulator/hart_test.c @@ -0,0 +1,251 @@ +#include <stdlib.h>
+#include <inttypes.h>
+#include <assert.h>
+#include <stdbool.h>
+
+#include "emulator/hart.h"
+
+static void test_addi()
+{
+ struct Hart hart = {0};
+
+ execute(&hart, 0x00500093); // addi x1, x0, 5
+ assert(hart.regs[1] == 5);
+
+ execute(&hart, 0xffe00093); // addi, x1, x0, -2
+ assert(hart.regs[1] == 0xfffffffe);
+}
+
+static void test_slti_sltiu()
+{
+ struct Hart hart = {0};
+
+ hart.regs[1] = 5;
+
+ execute(&hart, 0x00f0b113); // sltiu x2, x1, 15
+ assert(hart.regs[2] == 1);
+
+ execute(&hart, 0x0050b113); // sltiu x2, x1, 15
+ assert(hart.regs[2] == 0);
+
+ execute(&hart, 0x0010b113); // sltiu x2, x1, 15
+ assert(hart.regs[2] == 0);
+
+ execute(&hart, 0x00f0a113); // slti x2, x1, 15
+ assert(hart.regs[2] == 1);
+
+ execute(&hart, 0x0050a113); // slti x2, x1, 15
+ assert(hart.regs[2] == 0);
+
+ execute(&hart, 0x0010a113); // slti x2, x1, 15
+ assert(hart.regs[2] == 0);
+
+ execute(&hart, 0xffb0a113); // slti x2, x1, -5
+ assert(hart.regs[2] == 0);
+
+ hart.regs[1] = (uint32_t)-20;
+
+ execute(&hart, 0xffb0a113); // slti x2, x1, -5
+ assert(hart.regs[2] == 1);
+}
+
+static void test_andi_ori_xori()
+{
+ struct Hart hart = {0};
+
+ hart.regs[1] = 6;
+
+ execute(&hart, 0x00c0c113); // xori x2, x1, 12
+ assert(hart.regs[2] == 10);
+
+ execute(&hart, 0x00c0e113); // ori x2, x1, 12
+ assert(hart.regs[2] == 14);
+
+ execute(&hart, 0x00c0f113); // andi x2, x1, 12
+ assert(hart.regs[2] == 4);
+}
+
+static void test_slli_srli_srai()
+{
+ struct Hart hart = {0};
+
+ hart.regs[1] = 6;
+
+ execute(&hart, 0x00209113); // slli x2, x1, 2
+ assert(hart.regs[2] == 24);
+
+ execute(&hart, 0x0020d113); // srli x2, x1, 2
+ assert(hart.regs[2] == 1);
+
+ execute(&hart, 0x4020d113); // srai x2, x1, 2
+ assert(hart.regs[2] == 1);
+
+ hart.regs[1] = (uint32_t)-6;
+
+ execute(&hart, 0x0020d113); // srli x2, x1, 2
+ assert(hart.regs[2] == 0x3FFFFFFE);
+
+ execute(&hart, 0x4020d113); // srai x2, x1, 2
+ assert(hart.regs[2] == 0xFFFFFFFE);
+}
+
+static void test_lui_auipc()
+{
+ struct Hart hart = {0};
+
+ hart.pc = 0;
+ execute(&hart, 0x0007b0b7); // lui x1, 503808
+ assert(hart.regs[1] == 503808);
+
+ hart.pc = 0;
+ execute(&hart, 0x0007b097); // auipc x1, 503808
+ assert(hart.regs[1] == 503808);
+
+ hart.pc = 12;
+ execute(&hart, 0x0007b097); // auipc x1, 503808
+ assert(hart.regs[1] == 503820);
+}
+
+static void test_op()
+{
+ struct Hart hart = {0};
+
+ hart.regs[1] = 3;
+ hart.regs[2] = 4;
+ hart.regs[4] = (uint32_t)-1;
+
+ execute(&hart, 0x002081b3); // add, x3, x1, x2
+ assert(hart.regs[3] == 7);
+
+ execute(&hart, 0x402081b3); // sub x3, x1, x2
+ assert(hart.regs[3] == 0xFFFFFFFF);
+
+ execute(&hart, 0x0020a1b3); // slt x3, x1, x2
+ assert(hart.regs[3] == 1);
+
+ execute(&hart, 0x001121b3); // slt x3, x2, 1
+ assert(hart.regs[3] == 0);
+
+ execute(&hart, 0x001131b3); // sltu x3, x2, x1
+ assert(hart.regs[3] == 0);
+
+ execute(&hart, 0x0020b1b3); // sltu x3, x1, x2
+ assert(hart.regs[3] == 1);
+
+ execute(&hart, 0x0040a1b3); // slt x3, x1, x4
+ assert(hart.regs[3] == 0);
+
+ hart.regs[1] = 6;
+ hart.regs[2] = 12;
+
+ execute(&hart, 0x0020e1b3); // or x3, x1, x2
+ assert(hart.regs[3] == 14);
+
+ execute(&hart, 0x0020c1b3); // xor x3, x1, x2
+ assert(hart.regs[3] == 10);
+
+ execute(&hart, 0x0020f1b3); // and x3, x1, x2
+ assert(hart.regs[3] == 4);
+
+ hart.regs[1] = 6;
+ hart.regs[2] = 2;
+
+ execute(&hart, 0x002091b3); // sll x3, x1, x2
+ assert(hart.regs[3] == 24);
+
+ execute(&hart, 0x0020d1b3); // srl x3, x1, x2
+ assert(hart.regs[3] == 1);
+
+ execute(&hart, 0x4020d1b3); // sra x3, x1, x2
+ assert(hart.regs[3] == 1);
+
+ hart.regs[1] = (uint32_t)-6;
+ hart.regs[2] = 2;
+
+ execute(&hart, 0x4020d1b3); // sra x3, x1, x2
+ assert(hart.regs[3] == 0xFFFFFFFE);
+}
+
+static void test_jal()
+{
+ struct Hart hart = {0};
+
+ hart.pc = 12;
+
+ execute(&hart, 0x12c000ef); // jal x1, 300
+ assert(hart.regs[1] == 16);
+ assert(hart.pc == 312);
+
+ execute(&hart, 0xed5ff0ef); // jal x1, -300
+ assert(hart.regs[1] == 316);
+ assert(hart.pc == 12);
+}
+
+static void test_jalr()
+{
+ struct Hart hart = {0};
+
+ hart.pc = 12;
+ hart.regs[1] = 300;
+
+ execute(&hart, 0x00a08167); // jalr x2, 10(x1)
+ assert(hart.regs[2] == 16);
+ assert(hart.pc == 310);
+
+ execute(&hart, 0xff608167); // jalr x2, -10(x1)
+ assert(hart.regs[2] == 314);
+ assert(hart.pc == 290);
+}
+
+static void test_branch()
+{
+ struct Hart hart = {0};
+
+ hart.pc = 100;
+ hart.regs[1] = 2;
+ hart.regs[2] = 0xFFFFFFFC;
+
+ execute(&hart, 0x00208c63); // beq x1, x2, 24
+ assert(hart.pc == 104);
+
+ hart.pc = 100;
+ execute(&hart, 0x00209c63); // bne x1, x2, 24
+ assert(hart.pc == 124);
+
+ hart.pc = 100;
+ execute(&hart, 0x0020cc63); // blt x1, x2, 24
+ assert(hart.pc == 124);
+
+ hart.pc = 100;
+ execute(&hart, 0x0020dc63); // bge x1, x2, 24
+ assert(hart.pc == 104);
+
+ hart.pc = 100;
+ execute(&hart, 0x0020ec63); // bltu x1, x2, 24
+ assert(hart.pc == 104);
+
+ hart.pc = 100;
+ execute(&hart, 0x0020fc63); // bgeu x1, x2, 24
+ assert(hart.pc == 124);
+}
+
+void test()
+{
+ test_addi();
+ test_slti_sltiu();
+ test_andi_ori_xori();
+ test_slli_srli_srai();
+ test_lui_auipc();
+ test_op();
+ test_jal();
+ test_jalr();
+ test_branch();
+}
+
+int main(int argc, char* argv[])
+{
+ test();
+ return EXIT_SUCCESS;
+}
+
+#include "emulator/hart.c"
diff --git a/emulator/main.c b/emulator/main.c index ed875a3..a00a717 100644 --- a/emulator/main.c +++ b/emulator/main.c @@ -1,812 +1,12 @@ #include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
-#include <assert.h>
-#include <stdbool.h>
-#include <string.h>
-#define ET_NONE 0x00
-#define ET_REL 0x01
-#define ET_EXEC 0x02
-#define ET_DYN 0x03
-#define ET_CORE 0x04
-
-struct Elf32Header
-{
- uint8_t ident[16];
- uint16_t type;
- uint16_t machine;
- uint32_t version;
- uint32_t entry;
- uint32_t phoff;
- uint32_t shoff;
- uint32_t flags;
- uint16_t ehsize;
- uint16_t phentsize;
- uint16_t phnum;
- uint16_t shentsize;
- uint16_t shnum;
- uint16_t shstrndx;
-};
-
-#define PT_NULL 0x00000000
-#define PT_LOAD 0x00000001
-#define PT_DYNAMIC 0x00000002
-#define PT_INTERP 0x00000003
-#define PT_NOTE 0x00000004
-#define PT_SHLIB 0x00000005
-#define PT_PHDR 0x00000006
-#define PT_TLS 0x00000007
-
-#define PF_X 0x1
-#define PF_W 0x2
-#define PF_R 0x4
-
-struct Elf32ProgramHeader
-{
- uint32_t type;
- uint32_t offset;
- uint32_t vaddr;
- uint32_t paddr;
- uint32_t filesz;
- uint32_t memsz;
- uint32_t flags;
- uint32_t align;
-};
-
-bool load_elf(const char* file, char* mem, uint32_t mem_size, uint32_t* start_address)
-{
- FILE* fp = fopen(file, "rb");
- if (fp == NULL)
- {
- printf("Couldn't open input file\n");
- return false;
- }
-
- struct Elf32Header header;
- size_t read = fread(&header, sizeof(struct Elf32Header), 1, fp);
- if (read != 1)
- {
- printf("ELF header too small\n");
- return false;
- }
-
- static uint8_t kValidIdent[7] = {
- 0x7f, 0x45, 0x4c, 0x46,
- 1, 1, 1
- };
- if (memcmp(kValidIdent, header.ident, 7) != 0)
- {
- printf("Invalid ELF header\n");
- return false;
- }
-
- if (header.type != ET_EXEC)
- {
- printf("Can only link EXEC ELF files\n");
- return false;
- }
-
- memset(mem, 0, mem_size);
-
- assert(header.phnum == 0 || header.phentsize == sizeof(struct Elf32ProgramHeader));
- for (uint32_t i = 0; i < header.phnum; ++i)
- {
- struct Elf32ProgramHeader pheader;
-
- fseek(fp, header.phoff + i * header.phentsize, SEEK_SET);
- read = fread(&pheader, sizeof(struct Elf32ProgramHeader), 1, fp);
- if (read != 1)
- {
- printf("Error reading program header at index %u\n", i);
- return false;
- }
-
- if (pheader.type == PT_LOAD)
- {
- if (pheader.paddr + pheader.memsz > mem_size)
- {
- printf("Memory not large enough for ELF file\n");
- return false;
- }
-
- fseek(fp, pheader.offset, SEEK_SET);
- read = fread(mem + pheader.paddr, pheader.filesz, 1, fp);
- if (read != 1)
- {
- printf("Error when copying ELF segment\n");
- return false;
- }
- }
- }
-
- if (header.entry > mem_size)
- {
- printf("Entry address out of bounds\n");
- return false;
- }
-
- *start_address = header.entry;
- fclose(fp);
-
- return true;
-}
-
-inline uint32_t sign_extend(uint32_t word, uint32_t size)
-{
- const uint32_t mask = 1U << (size - 1);
- return (word ^ mask) - mask;
-}
-
-struct Instruction
-{
- uint8_t opcode;
- uint8_t rs1;
- uint8_t rs2;
- uint8_t rd;
- uint8_t funct3;
- uint8_t funct7;
- uint32_t imm;
-};
-
-struct Instruction decode_r_type(uint32_t word)
-{
- struct 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;
-};
-
-struct Instruction decode_i_type(uint32_t word)
-{
- struct 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;
-};
-
-struct Instruction decode_s_type(uint32_t word)
-{
- struct 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;
-};
-
-struct Instruction decode_b_type(uint32_t word)
-{
- struct Instruction instruction = decode_s_type(word);
- instruction.imm = ((instruction.imm << 11) & 0x800) | (instruction.imm & 0xfffff7ff);
- return instruction;
-};
-
-struct Instruction decode_u_type(uint32_t word)
-{
- struct Instruction instruction = {0};
- instruction.opcode = word & 0x7F;
- instruction.rd = (word >> 7) & 0x1F;
- instruction.imm = word & 0xFFFFF000;
- return instruction;
-};
-
-struct Instruction decode_j_type(uint32_t word)
-{
- struct 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;
-}
-
-struct Hart
-{
- uint32_t pc;
- uint32_t regs[32];
- char* mem;
- uint32_t mem_size;
-};
-
-void execute_op_imm(struct Hart* hart, uint32_t instruction)
-{
- const struct Instruction inst = decode_i_type(instruction);
- if (inst.rd == 0) return;
-
- switch (inst.funct3)
- {
- case 0: // ADDI
- hart->regs[inst.rd] = hart->regs[inst.rs1] + inst.imm;
- break;
- case 1: // SLLI
- hart->regs[inst.rd] = hart->regs[inst.rs1] << (inst.imm & 0x1F);
- break;
- case 2: // SLTI
- hart->regs[inst.rd] = (int32_t)hart->regs[inst.rs1] < (int32_t)inst.imm ? 1 : 0;
- break;
- case 3: // SLTIU
- hart->regs[inst.rd] = hart->regs[inst.rs1] < inst.imm ? 1 : 0;
- break;
- case 4: // XORI
- hart->regs[inst.rd] = hart->regs[inst.rs1] ^ inst.imm;
- break;
- case 5: // SRLI, SRAI
- {
- const uint32_t shamt = inst.imm & 0x1F;
- uint32_t res = hart->regs[inst.rs1] >> shamt;
- if ((inst.imm & 0x400) && shamt > 0) { res = sign_extend(res, 32 - shamt); }
- hart->regs[inst.rd] = res;
- break;
- }
- case 6: // ORI
- hart->regs[inst.rd] = hart->regs[inst.rs1] | inst.imm;
- break;
- case 7: // ANDI
- hart->regs[inst.rd] = hart->regs[inst.rs1] & inst.imm;
- break;
- default:
- assert(!"Unhandled OP-IMM");
- }
-}
-
-void execute_op(struct Hart* hart, uint32_t instruction)
-{
- const struct Instruction inst = decode_r_type(instruction);
- if (inst.rd == 0) return;
-
- switch (inst.funct3)
- {
- case 0: // ADD, SUB
- if (instruction & 0x40000000)
- {
- hart->regs[inst.rd] = hart->regs[inst.rs1] - hart->regs[inst.rs2];
- }
- else
- {
- hart->regs[inst.rd] = hart->regs[inst.rs1] + hart->regs[inst.rs2];
- }
- break;
- case 1: // SLL
- hart->regs[inst.rd] = hart->regs[inst.rs1] << (hart->regs[inst.rs2] & 0x1F);
- break;
- case 2: // SLT
- hart->regs[in |