804 lines
26 KiB
C
804 lines
26 KiB
C
// https://docs.riscv.org/reference/isa/_attachments/riscv-unprivileged.pdf
|
|
// https://riscv.org/wp-content/uploads/2024/12/riscv-calling.pdf
|
|
#include <gelf.h>
|
|
#include <libelf.h>
|
|
#include <stdint.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
#define PARSE_I_INS(ins) \
|
|
uint8_t rd = (ins >> 7) & 0b11111; \
|
|
uint8_t funct3 = (ins >> 12) & 0b111; \
|
|
uint8_t rs1 = (ins >> 15) & 0b11111; \
|
|
int32_t imm = ((int32_t)ins) >> 20
|
|
|
|
#define PARSE_R_INS(ins) \
|
|
uint8_t rd = (ins >> 7) & 0b11111; \
|
|
uint8_t funct3 = (ins >> 12) & 0b111; \
|
|
uint8_t rs1 = (ins >> 15) & 0b11111; \
|
|
uint8_t rs2 = (ins >> 20) & 0b11111; \
|
|
int32_t funct7 = ((int32_t)ins) >> 25
|
|
|
|
#define PARSE_B_INS(ins) \
|
|
uint8_t funct3 = (ins >> 12) & 0b111; \
|
|
uint8_t rs1 = (ins >> 15) & 0b11111; \
|
|
uint8_t rs2 = (ins >> 20) & 0b11111; \
|
|
int32_t imm_12 = (ins >> 31) & 0b1; \
|
|
int32_t imm_10_5 = (ins >> 25) & 0b111111; \
|
|
int32_t imm_4_1 = (ins >> 8) & 0b1111; \
|
|
int32_t imm_11 = (ins >> 7) & 0b1; \
|
|
int32_t imm = \
|
|
(imm_12 << 12) | (imm_11 << 11) | (imm_10_5 << 5) | (imm_4_1 << 1); \
|
|
imm = (imm << 19) >> 19
|
|
|
|
#define PARSE_S_INS(ins) \
|
|
uint8_t funct3 = (ins >> 12) & 0b111; \
|
|
uint8_t rs1 = (ins >> 15) & 0b11111; \
|
|
uint8_t rs2 = (ins >> 20) & 0b11111; \
|
|
int32_t imm_11_5 = (ins >> 25) & 0b1111111; \
|
|
int32_t imm_4_0 = (ins >> 7) & 0b11111; \
|
|
int32_t imm = (imm_11_5 << 5) | imm_4_0; \
|
|
imm = (imm << 20) >> 20
|
|
|
|
#define PARSE_J_INS(ins) \
|
|
uint8_t rd = (ins >> 7) & 0b11111; \
|
|
int32_t imm_20 = (ins >> 31) & 0b1; \
|
|
int32_t imm_10_1 = (ins >> 21) & 0b1111111111; \
|
|
int32_t imm_11 = (ins >> 20) & 0b1; \
|
|
int32_t imm_19_12 = (ins >> 12) & 0b11111111; \
|
|
int32_t imm = \
|
|
(imm_20 << 20) | (imm_19_12 << 12) | (imm_11 << 11) | (imm_10_1 << 1); \
|
|
imm = (imm << 11) >> 11
|
|
|
|
#define PARSE_U_INS(ins) \
|
|
uint8_t rd = (ins >> 7) & 0b11111; \
|
|
int32_t imm = ins >> 12
|
|
|
|
static const char *const REGS[32] = {
|
|
"zero", "ra", "sp", "gp", "tp", "t0", "t1", "t2", "fp", "s1", "a0",
|
|
"a1", "a2", "a3", "a4", "a5", "a6", "a7", "s2", "s3", "s4", "s5",
|
|
"s6", "s7", "s8", "s9", "s10", "s11", "t3", "t4", "t5", "t6"};
|
|
|
|
typedef struct {
|
|
size_t offset;
|
|
size_t size;
|
|
size_t entrypoint;
|
|
} Section;
|
|
|
|
typedef struct {
|
|
uint8_t *memory;
|
|
size_t pc;
|
|
int64_t regs[32];
|
|
Section code_section;
|
|
} RISCV64;
|
|
|
|
Section riscv64_get_code_section(uint8_t *exe_bytes, size_t exe_size) {
|
|
Elf *elf = elf_memory((char *)exe_bytes, exe_size);
|
|
if (!elf) {
|
|
fprintf(stderr, "elf_begin failed: %s\n", elf_errmsg(-1));
|
|
exit(1);
|
|
}
|
|
|
|
size_t str_table_index;
|
|
if (elf_getshdrstrndx(elf, &str_table_index) != 0) {
|
|
fprintf(stderr, "elf_getshdrstrndx failed: %s\n", elf_errmsg(-1));
|
|
exit(1);
|
|
}
|
|
|
|
GElf_Ehdr ehdr;
|
|
if (gelf_getehdr(elf, &ehdr) == 0) {
|
|
fprintf(stderr, "gelf_getehdr failed: %s\n", elf_errmsg(-1));
|
|
exit(1);
|
|
}
|
|
|
|
Elf_Scn *section = NULL;
|
|
while ((section = elf_nextscn(elf, section)) != NULL) {
|
|
GElf_Shdr header;
|
|
if (gelf_getshdr(section, &header) != &header)
|
|
continue;
|
|
|
|
const char *name = elf_strptr(elf, str_table_index, header.sh_name);
|
|
if (name && strcmp(name, ".text") == 0) {
|
|
elf_end(elf);
|
|
return (Section){.offset = header.sh_offset,
|
|
.size = header.sh_size,
|
|
.entrypoint =
|
|
ehdr.e_entry - header.sh_addr + header.sh_offset};
|
|
}
|
|
}
|
|
|
|
fprintf(stderr, "Failed to locate .text\n");
|
|
exit(1);
|
|
}
|
|
|
|
RISCV64 riscv64_load(uint8_t *exe_bytes, size_t exe_size) {
|
|
Section section = riscv64_get_code_section(exe_bytes, exe_size);
|
|
|
|
return (RISCV64){
|
|
.memory = exe_bytes,
|
|
.pc = section.offset,
|
|
.regs = {0},
|
|
.code_section = section,
|
|
};
|
|
}
|
|
|
|
void riscv64_dump(const RISCV64 *r) {
|
|
printf("REGS:");
|
|
for (size_t i = 0; i < 32; i++) {
|
|
printf(" %lu", r->regs[i]);
|
|
}
|
|
printf("\n");
|
|
}
|
|
|
|
void riscv64_disassemble_one(const RISCV64 *r) {
|
|
uint32_t ins;
|
|
memcpy(&ins, r->memory + r->pc, 4);
|
|
|
|
uint16_t opcode = ins & 0b1111111;
|
|
|
|
// https://stackoverflow.com/questions/62939410/how-can-i-find-out-the-instruction-format-of-a-risc-v-instruction
|
|
switch (opcode) {
|
|
case 0b1100011: {
|
|
PARSE_B_INS(ins);
|
|
|
|
if (funct3 == 0b000) {
|
|
printf("beq %s, %s, %d\n", REGS[rs1], REGS[rs2], imm);
|
|
} else if (funct3 == 0b001) {
|
|
printf("bne %s, %s, %d\n", REGS[rs1], REGS[rs2], imm);
|
|
} else if (funct3 == 0b100) {
|
|
printf("blt %s, %s, %d\n", REGS[rs1], REGS[rs2], imm);
|
|
} else if (funct3 == 0b101) {
|
|
printf("bge %s, %s, %d\n", REGS[rs1], REGS[rs2], imm);
|
|
} else if (funct3 == 0b110) {
|
|
printf("bltu %s, %s, %d\n", REGS[rs1], REGS[rs2], imm);
|
|
} else {
|
|
fprintf(stderr, "B-type: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0010011: {
|
|
PARSE_I_INS(ins);
|
|
|
|
if (funct3 == 0b000) {
|
|
printf("addi %s, %s, %d\n", REGS[rd], REGS[rs1], imm);
|
|
} else if (funct3 == 0b001) {
|
|
uint32_t shamt = (ins >> 20) & 0b111111;
|
|
uint32_t funct6 = (ins >> 26) & 0b111111;
|
|
|
|
if (funct6 == 0b000000) {
|
|
printf("slli %s, %s, %d\n", REGS[rd], REGS[rs1], shamt);
|
|
} else {
|
|
fprintf(stderr, "I-type 1: funct3=001: unrecognized funct6: %b\n",
|
|
funct6);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b011) {
|
|
printf("sltiu %s, %s, %d\n", REGS[rd], REGS[rs1], imm);
|
|
} else if (funct3 == 0b100) {
|
|
printf("xori %s, %s, %d\n", REGS[rd], REGS[rs1], imm);
|
|
} else if (funct3 == 0b101) {
|
|
// of course this one just has to be different
|
|
uint32_t shamt = (ins >> 20) & 0b111111;
|
|
uint32_t funct6 = (ins >> 26) & 0b111111;
|
|
|
|
if (funct6 == 0b000000) {
|
|
printf("srli %s, %s, %d\n", REGS[rd], REGS[rs1], shamt);
|
|
} else if (funct6 == 0b010000) {
|
|
printf("srai %s, %s, %d\n", REGS[rd], REGS[rs1], shamt);
|
|
} else {
|
|
fprintf(stderr, "I-type 1: funct3=101: unrecognized funct6: %b\n",
|
|
funct6);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b111) {
|
|
printf("andi %s, %s, %d\n", REGS[rd], REGS[rs1], imm);
|
|
} else {
|
|
fprintf(stderr, "I-type 1: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0000011: {
|
|
PARSE_I_INS(ins);
|
|
|
|
if (funct3 == 0b000) {
|
|
printf("lb %s, %d(%s)\n", REGS[rd], imm, REGS[rs1]);
|
|
} else if (funct3 == 0b001) {
|
|
printf("lh %s, %d(%s)\n", REGS[rd], imm, REGS[rs1]);
|
|
} else if (funct3 == 0b010) {
|
|
printf("lw %s, %d(%s)\n", REGS[rd], imm, REGS[rs1]);
|
|
} else if (funct3 == 0b011) {
|
|
printf("ld %s, %d(%s)\n", REGS[rd], imm, REGS[rs1]);
|
|
} else if (funct3 == 0b100) {
|
|
printf("lbu %s, %d(%s)\n", REGS[rd], imm, REGS[rs1]);
|
|
} else {
|
|
fprintf(stderr, "I-type 2: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b1100111: {
|
|
PARSE_I_INS(ins);
|
|
printf("jalr %s, %s, %d\n", REGS[rd], REGS[rs1], imm);
|
|
}; break;
|
|
case 0b1110011: {
|
|
PARSE_I_INS(ins);
|
|
|
|
if (funct3 == 0b000) {
|
|
if (imm == 0) {
|
|
printf("ecall\n");
|
|
} else {
|
|
fprintf(stderr, "I-type 4: funct3=000 unrecognized imm: %b\n", imm);
|
|
exit(1);
|
|
}
|
|
} else {
|
|
fprintf(stderr, "I-type 4: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b1101111: {
|
|
PARSE_J_INS(ins);
|
|
printf("jal %s, %d\n", REGS[rd], imm);
|
|
}; break;
|
|
case 0b0110011: {
|
|
PARSE_R_INS(ins);
|
|
if (funct3 == 0b000) {
|
|
if (funct7 == 0b0000000) {
|
|
printf("add %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else if (funct7 == 0b0100000) {
|
|
printf("sub %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else if (funct7 == 0b0000001) {
|
|
printf("mul %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b000: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b001) {
|
|
if (funct7 == 0b0000001) {
|
|
printf("mulh %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b001: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b010) {
|
|
if (funct7 == 0b0000000) {
|
|
printf("slt %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b010: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b011) {
|
|
if (funct7 == 0b0000000) {
|
|
printf("sltu %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else if (funct7 == 0b0000001) {
|
|
printf("mulhu %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b011: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b100) {
|
|
if (funct7 == 0b0000000) {
|
|
printf("xor %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else if (funct7 == 0b0000001) {
|
|
printf("div %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b100: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b110) {
|
|
if (funct7 == 0b0000001) {
|
|
printf("rem %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else if (funct7 == 0b0000000) {
|
|
printf("or %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b110: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b111) {
|
|
if (funct7 == 0b000) {
|
|
printf("and %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b111: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else {
|
|
fprintf(stderr, "R-type 1: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0101111:
|
|
fprintf(stderr, "R-type 2: unimplemented\n");
|
|
exit(1);
|
|
case 0b0111011: {
|
|
PARSE_R_INS(ins);
|
|
if (funct3 == 0b000) {
|
|
if (funct7 == 0b0000000) {
|
|
printf("addw %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else if (funct7 == 0b0100000) {
|
|
printf("subw %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else if (funct7 == 0b0000001) {
|
|
printf("mulw %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 3: funct3=000: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b101) {
|
|
if (funct7 == 0b0000001) {
|
|
printf("divuw %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 3: funct3=101: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b111) {
|
|
printf("remuw %s, %s, %s\n", REGS[rd], REGS[rs1], REGS[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 3: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0011011: {
|
|
uint8_t funct3 = (ins >> 12) & 0b111;
|
|
if (funct3 == 0b000) {
|
|
PARSE_I_INS(ins);
|
|
printf("addiw %s, %s, %d\n", REGS[rd], REGS[rs1], imm);
|
|
} else if (funct3 == 0b001) {
|
|
PARSE_I_INS(ins);
|
|
printf("slliw %s, %s, %d\n", REGS[rd], REGS[rs1], imm);
|
|
} else {
|
|
fprintf(stderr, "R-type 4: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0100011: {
|
|
PARSE_S_INS(ins);
|
|
|
|
if (funct3 == 0b000) {
|
|
printf("sb %s, %d(%s)\n", REGS[rs2], imm, REGS[rs1]);
|
|
} else if (funct3 == 0b001) {
|
|
printf("sh %s, %d(%s)\n", REGS[rs2], imm, REGS[rs1]);
|
|
} else if (funct3 == 0b010) {
|
|
printf("sw %s, %d(%s)\n", REGS[rs2], imm, REGS[rs1]);
|
|
} else if (funct3 == 0b011) {
|
|
printf("sd %s, %d(%s)\n", REGS[rs2], imm, REGS[rs1]);
|
|
} else {
|
|
fprintf(stderr, "S-type: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0110111: {
|
|
PARSE_U_INS(ins);
|
|
printf("lui %s, %d\n", REGS[rd], imm);
|
|
}; break;
|
|
case 0b0010111: {
|
|
PARSE_U_INS(ins);
|
|
printf("auipc %s, %d\n", REGS[rd], imm);
|
|
}; break;
|
|
default:
|
|
fprintf(stderr, "Unrecognized opcode: %07b\n", opcode);
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
void riscv64_execute(RISCV64 *r) {
|
|
r->pc = r->code_section.entrypoint;
|
|
|
|
r->regs[2] = (20 * 1024 * 1024) - 1; // set the stack pointer
|
|
|
|
while (r->pc < r->code_section.offset + r->code_section.size) {
|
|
r->regs[0] = 0; // clear the zero register
|
|
|
|
uint32_t ins;
|
|
memcpy(&ins, r->memory + r->pc, 4);
|
|
|
|
uint16_t opcode = ins & 0b1111111;
|
|
|
|
// https://stackoverflow.com/questions/62939410/how-can-i-find-out-the-instruction-format-of-a-risc-v-instruction
|
|
switch (opcode) {
|
|
case 0b1100011: {
|
|
PARSE_B_INS(ins);
|
|
|
|
if (funct3 == 0b000) { // beq
|
|
if (r->regs[rs1] == r->regs[rs2]) {
|
|
r->pc += imm;
|
|
continue;
|
|
}
|
|
} else if (funct3 == 0b001) { // bne
|
|
if (r->regs[rs1] != r->regs[rs2]) {
|
|
r->pc += imm;
|
|
continue;
|
|
}
|
|
} else if (funct3 == 0b101) { // bge
|
|
if (r->regs[rs1] >= r->regs[rs2]) {
|
|
r->pc += imm;
|
|
continue;
|
|
}
|
|
} else if (funct3 == 0b100) { // blt
|
|
if (r->regs[rs1] < r->regs[rs2]) {
|
|
r->pc += imm;
|
|
continue;
|
|
}
|
|
} else if (funct3 == 0b110) { // bltu
|
|
if ((uint64_t)r->regs[rs1] < (uint64_t)r->regs[rs2]) {
|
|
r->pc += imm;
|
|
continue;
|
|
}
|
|
} else {
|
|
fprintf(stderr, "B-type: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0010011: {
|
|
PARSE_I_INS(ins);
|
|
|
|
if (funct3 == 0b000) { // addi
|
|
r->regs[rd] = r->regs[rs1] + imm;
|
|
} else if (funct3 == 0b001) { // slli
|
|
uint32_t shamt = (ins >> 20) & 0b111111;
|
|
uint32_t funct6 = (ins >> 26) & 0b111111;
|
|
|
|
if (funct6 == 0b000000) {
|
|
r->regs[rd] = r->regs[rs1] << shamt;
|
|
} else {
|
|
fprintf(stderr, "I-type 1: funct3=001: unrecognized funct6: %b\n",
|
|
funct6);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b011) { // sltiu
|
|
r->regs[rd] = (r->regs[rs1] < (uint64_t)(int64_t)imm) ? 1 : 0;
|
|
} else if (funct3 == 0b100) { // xori
|
|
r->regs[rd] = r->regs[rs1] ^ imm;
|
|
} else if (funct3 == 0b101) {
|
|
// of course this one just has to be different
|
|
uint32_t shamt = (ins >> 20) & 0b111111;
|
|
uint32_t funct6 = (ins >> 26) & 0b111111;
|
|
|
|
if (funct6 == 0b000000) { // srli
|
|
r->regs[rd] = r->regs[rs1] >> shamt;
|
|
} else if (funct6 == 0b010000) { // srai
|
|
r->regs[rd] = (int32_t)r->regs[rs1] >> shamt;
|
|
} else {
|
|
fprintf(stderr, "I-type 1: funct3=101: unrecognized funct6: %b\n",
|
|
funct6);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b111) {
|
|
r->regs[rd] = r->regs[rs1] & imm;
|
|
} else {
|
|
fprintf(stderr, "I-type 1: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0000011: {
|
|
PARSE_I_INS(ins);
|
|
|
|
if (funct3 == 0b000) { // lb
|
|
r->regs[rd] = (int8_t)r->memory[r->regs[rs1] + imm];
|
|
} else if (funct3 == 0b001) { // lh
|
|
r->regs[rd] = *(int16_t *)&r->memory[r->regs[rs1] + imm];
|
|
} else if (funct3 == 0b010) { // lw
|
|
r->regs[rd] = *(int32_t *)&r->memory[r->regs[rs1] + imm];
|
|
} else if (funct3 == 0b011) { // ld
|
|
r->regs[rd] = *(uint64_t *)&r->memory[r->regs[rs1] + imm];
|
|
} else if (funct3 == 0b100) { // lbu
|
|
r->regs[rd] = r->memory[r->regs[rs1] + imm];
|
|
} else {
|
|
fprintf(stderr, "I-type 2: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b1100111: { // jalr
|
|
PARSE_I_INS(ins);
|
|
size_t target = (r->regs[rs1] + imm) & ~(size_t)1;
|
|
r->regs[rd] = r->pc + 4;
|
|
r->pc = target;
|
|
continue;
|
|
}; break;
|
|
case 0b1110011: {
|
|
PARSE_I_INS(ins);
|
|
|
|
if (funct3 == 0b000) {
|
|
if (imm == 0) { // ecall
|
|
// https://jborza.com/post/2021-05-11-riscv-linux-syscalls/
|
|
switch (r->regs[17]) {
|
|
case 63: { // read
|
|
if (r->regs[10] != 0) {
|
|
fprintf(stderr, "read syscall implemented only for stdin.\n");
|
|
exit(1);
|
|
}
|
|
|
|
size_t start = r->regs[11];
|
|
size_t count = r->regs[12];
|
|
size_t bytes_read = 0;
|
|
|
|
for (size_t i = 0; i < count; i++) {
|
|
int c = getchar();
|
|
if (c == EOF)
|
|
break;
|
|
r->memory[start + i] = (uint8_t)c;
|
|
bytes_read++;
|
|
if (c == '\n')
|
|
break;
|
|
}
|
|
|
|
r->regs[10] = bytes_read;
|
|
}; break;
|
|
case 64: { // write
|
|
if (r->regs[10] != 1) {
|
|
fprintf(stderr, "write syscall implemented only for stdout.\n");
|
|
exit(1);
|
|
}
|
|
|
|
size_t start = r->regs[11];
|
|
size_t end = r->regs[11] + r->regs[12];
|
|
|
|
for (size_t i = start; i < end; i++) {
|
|
putchar(r->memory[i]);
|
|
}
|
|
}; break;
|
|
case 93: { // exit
|
|
printf("Program exited with code %lu.\n", r->regs[10]);
|
|
return;
|
|
}; break;
|
|
case 169: { // gettimeofday
|
|
// TODO: actually return the time
|
|
int64_t tv_addr = r->regs[10];
|
|
int64_t tz_addr = r->regs[11];
|
|
|
|
uint8_t tv_buf[16] = {
|
|
0xD2, 0x02, 0x96, 0x49,
|
|
0x00, 0x00, 0x00, 0x00, // tv_sec = 1234567890
|
|
0x00, 0x00, 0x00, 0x00,
|
|
0x00, 0x00, 0x00, 0x00, // tv_usec = 0
|
|
};
|
|
memcpy(&r->memory[tv_addr], tv_buf, 16);
|
|
|
|
memset(&r->memory[tz_addr], 0, 8);
|
|
|
|
r->regs[10] = 0;
|
|
}; break;
|
|
default:
|
|
fprintf(stderr, "Unimplemented syscall: %lu\n", r->regs[17]);
|
|
exit(1);
|
|
}
|
|
break;
|
|
} else {
|
|
fprintf(stderr, "I-type 4: funct3=000 unrecognized imm: %b\n", imm);
|
|
exit(1);
|
|
};
|
|
break;
|
|
} else {
|
|
fprintf(stderr, "I-type 4: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b1101111: { // jal
|
|
PARSE_J_INS(ins);
|
|
r->regs[rd] = r->pc + 4;
|
|
r->pc += imm;
|
|
continue;
|
|
}; break;
|
|
case 0b0110011: {
|
|
PARSE_R_INS(ins);
|
|
if (funct3 == 0b000) {
|
|
if (funct7 == 0b0000000) { // add
|
|
r->regs[rd] = r->regs[rs1] + r->regs[rs2];
|
|
} else if (funct7 == 0b0100000) { // sub
|
|
r->regs[rd] = r->regs[rs1] - r->regs[rs2];
|
|
} else if (funct7 == 0b0000001) { // mul
|
|
r->regs[rd] = r->regs[rs1] * r->regs[rs2];
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b000: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b001) {
|
|
if (funct7 == 0b0000001) { // mulh
|
|
int64_t a_hi = r->regs[rs1] >> 32;
|
|
int64_t b_hi = r->regs[rs2] >> 32;
|
|
uint64_t a_lo = (uint32_t)r->regs[rs1];
|
|
uint64_t b_lo = (uint32_t)r->regs[rs2];
|
|
uint64_t p0 = a_lo * b_lo;
|
|
int64_t p1 = a_hi * b_lo;
|
|
int64_t p2 = b_hi * a_lo;
|
|
int64_t p3 = a_hi * b_hi;
|
|
int64_t carry = (p0 >> 32);
|
|
int64_t mid = p1 + p2 + carry;
|
|
r->regs[rd] = p3 + (mid >> 32);
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b001: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b010) {
|
|
if (funct7 == 0b0000000) { // slt
|
|
r->regs[rd] = ((int64_t)r->regs[rs1] < (int64_t)r->regs[rs2]) ? 1 : 0;
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b010: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b011) {
|
|
if (funct7 == 0b0000000) { // sltu
|
|
r->regs[rd] =
|
|
((uint64_t)r->regs[rs1] < (uint64_t)r->regs[rs2]) ? 1 : 0;
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b011: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b100) {
|
|
if (funct7 == 0b0000000) { // xor
|
|
r->regs[rd] = r->regs[rs1] ^ r->regs[rs2];
|
|
} else if (funct7 == 0b0000001) { // div
|
|
if (r->regs[rs2] == 0) {
|
|
r->regs[rd] = -1;
|
|
} else {
|
|
r->regs[rd] = (int64_t)r->regs[rs1] / (int64_t)r->regs[rs2];
|
|
}
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b100: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b110) {
|
|
if (funct7 == 0b0000001) { // rem
|
|
if (r->regs[rs2] == 0) {
|
|
r->regs[rd] = r->regs[rs1];
|
|
} else {
|
|
r->regs[rd] = (int64_t)r->regs[rs1] % (int64_t)r->regs[rs2];
|
|
}
|
|
} else if (funct7 == 0b0000000) { // or
|
|
r->regs[rd] = r->regs[rs1] | r->regs[rs2];
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b110: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b111) {
|
|
if (funct7 == 0b000) { // and
|
|
r->regs[rd] = r->regs[rs1] & r->regs[rs2];
|
|
} else {
|
|
fprintf(stderr, "R-type 1: funct3=0b111: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else {
|
|
fprintf(stderr, "R-type 1: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0111011: {
|
|
PARSE_R_INS(ins);
|
|
if (funct3 == 0b000) {
|
|
if (funct7 == 0b0000000) { // addw
|
|
r->regs[rd] = (int32_t)(r->regs[rs1] + r->regs[rs2]);
|
|
} else if (funct7 == 0b0100000) { // subw
|
|
r->regs[rd] = (int32_t)(r->regs[rs1] - r->regs[rs2]);
|
|
} else if (funct7 == 0b0000001) { // mulw
|
|
r->regs[rd] = (int32_t)(r->regs[rs1] * r->regs[rs2]);
|
|
} else {
|
|
fprintf(stderr, "R-type 3: funct3=000: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b101) {
|
|
if (funct7 == 0b0000001) { // divuw
|
|
if (r->regs[rs2] == 0) {
|
|
r->regs[rd] = -1LL;
|
|
} else {
|
|
r->regs[rd] =
|
|
(int32_t)((uint32_t)r->regs[rs1] / (uint32_t)r->regs[rs2]);
|
|
}
|
|
} else {
|
|
fprintf(stderr, "R-type 3: funct3=101: unrecognized funct7: %b\n",
|
|
funct7);
|
|
exit(1);
|
|
}
|
|
} else if (funct3 == 0b111) { // remuw
|
|
if (r->regs[rs2] == 0) {
|
|
r->regs[rd] = (int32_t)r->regs[rs1];
|
|
} else {
|
|
r->regs[rd] =
|
|
(int32_t)((uint32_t)r->regs[rs1] % (uint32_t)r->regs[rs2]);
|
|
}
|
|
} else {
|
|
fprintf(stderr, "R-type 3: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0011011: {
|
|
PARSE_I_INS(ins);
|
|
if (funct3 == 0b000) { // addiw
|
|
r->regs[rd] = (int32_t)r->regs[rs1] + (int32_t)imm;
|
|
} else if (funct3 == 0b001) {
|
|
uint32_t shamt = (ins >> 20) & 0b11111;
|
|
r->regs[rd] = (int32_t)r->regs[rs1] << shamt;
|
|
} else {
|
|
fprintf(stderr, "R-type 4: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0100011: {
|
|
PARSE_S_INS(ins);
|
|
|
|
if (funct3 == 0b000) { // sb
|
|
size_t addr = r->regs[rs1] + imm;
|
|
r->memory[addr] = r->regs[rs2];
|
|
} else if (funct3 == 0b001) { // sh
|
|
size_t addr = r->regs[rs1] + imm;
|
|
*(uint16_t *)(&r->memory[addr]) = r->regs[rs2];
|
|
} else if (funct3 == 0b010) { // sw
|
|
size_t addr = r->regs[rs1] + imm;
|
|
*(uint32_t *)(&r->memory[addr]) = r->regs[rs2];
|
|
} else if (funct3 == 0b011) { // sd
|
|
size_t addr = r->regs[rs1] + imm;
|
|
// take this rust
|
|
*(uint64_t *)(&r->memory[addr]) = r->regs[rs2];
|
|
} else {
|
|
fprintf(stderr, "S-type: unrecognized funct3: %03b\n", funct3);
|
|
exit(1);
|
|
}
|
|
}; break;
|
|
case 0b0110111: { // lui
|
|
PARSE_U_INS(ins);
|
|
r->regs[rd] = (int64_t)imm << 12;
|
|
}; break;
|
|
case 0b0010111: { // auipc
|
|
PARSE_U_INS(ins);
|
|
r->regs[rd] = r->pc + ((int64_t)imm << 12);
|
|
}; break;
|
|
default:
|
|
fprintf(stderr, "Unrecognized opcode: %07b\n", opcode);
|
|
exit(1);
|
|
}
|
|
|
|
r->pc += 4;
|
|
}
|
|
}
|
|
|
|
int main(int argc, char *argv[]) {
|
|
if (elf_version(EV_CURRENT) == EV_NONE) {
|
|
fprintf(stderr, "Failed to initialize libelf: %s\n", elf_errmsg(-1));
|
|
return 1;
|
|
}
|
|
|
|
const char *path = NULL;
|
|
for (int i = 1; i < argc; i++) {
|
|
path = argv[i];
|
|
}
|
|
|
|
if (path == NULL) {
|
|
fprintf(stderr, "Usage: %s <path>\n", argv[0]);
|
|
return 1;
|
|
}
|
|
|
|
FILE *file = fopen(path, "rb");
|
|
if (!file) {
|
|
fprintf(stderr, "Failed to open %s\n", path);
|
|
return 1;
|
|
}
|
|
|
|
// probably enough for anything we can handle
|
|
uint8_t *exe_bytes = malloc(20 * 1024 * 1024);
|
|
size_t exe_size = fread(exe_bytes, 1, 20 * 1024 * 1024, file);
|
|
fclose(file);
|
|
|
|
RISCV64 r = riscv64_load(exe_bytes, exe_size);
|
|
|
|
for (r.pc = r.code_section.offset;
|
|
r.pc < r.code_section.offset + r.code_section.size; r.pc += 4) {
|
|
riscv64_disassemble_one(&r);
|
|
}
|
|
printf("END DISASSEMBLY\n");
|
|
|
|
riscv64_execute(&r);
|
|
}
|