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Multiplication

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This commit is contained in:
Steven Le Rouzic
2024-05-12 15:29:16 +02:00
parent 822fd8616c
commit 8ebaea4583
2 changed files with 121 additions and 48 deletions
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55
emulator/hart.c
View File

@ -45,6 +45,12 @@ static inline uint32_t sign_extend(uint32_t word, uint32_t size)
return (word ^ mask) - mask;
}
static inline uint64_t sign_extend_64(uint64_t word, uint32_t size)
{
const uint64_t mask = 1ULL << (size - 1);
return (word ^ mask) - mask;
}
struct Instruction
{
uint8_t opcode;
@ -166,10 +172,13 @@ static void execute_op(Hart* hart, uint32_t instruction)
const Instruction inst = decode_r_type(instruction);
if (inst.rd == 0) return;
uint32_t bank = inst.funct7 & 0x5F;
if (bank == 0)
{
switch (inst.funct3)
{
case 0: // ADD, SUB
if (instruction & 0x40000000)
if (inst.funct7 & 0x20)
{
hart->regs[inst.rd] = hart->regs[inst.rs1] - hart->regs[inst.rs2];
}
@ -194,7 +203,7 @@ static void execute_op(Hart* hart, uint32_t instruction)
{
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); }
if ((inst.funct7 & 0x20) && shamt > 0) { res = sign_extend(res, 32 - shamt); }
hart->regs[inst.rd] = res;
break;
}
@ -205,7 +214,39 @@ static void execute_op(Hart* hart, uint32_t instruction)
hart->regs[inst.rd] = hart->regs[inst.rs1] & hart->regs[inst.rs2];
break;
default:
assert(!"Unhandled OP-IMM");
assert(!"Unhandled OP, bank = 0");
break;
}
}
else if (bank == 1)
{
if ((inst.funct3 & 0x8) == 0)
{
uint64_t a = hart->regs[inst.rs1];
uint64_t b = hart->regs[inst.rs2];
switch (inst.funct3 & 0x3)
{
case 1: // MULH
b = sign_extend_64(b, 32);
case 2: // MULHSU
a = sign_extend_64(a, 32);
case 0: // MUL
case 3: // MULHU
break;
}
uint64_t r = a * b;
hart->regs[inst.rd] = (inst.funct3 == 0) ? r & 0xFFFFFFFF : r >> 32;
}
else
{
assert(!"Unhandled M OP");
}
}
else
{
assert(!"Unhandled OP bank");
}
}
@ -292,7 +333,7 @@ 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)
static void execute_load(Hart* hart, uint32_t instruction)
{
const Instruction inst = decode_i_type(instruction);
const uint32_t address = hart->regs[inst.rs1] + inst.imm;
@ -329,7 +370,7 @@ static void execute_op_load(Hart* hart, uint32_t instruction)
}
}
static void execute_op_store(Hart* hart, uint32_t instruction)
static void execute_store(Hart* hart, uint32_t instruction)
{
const Instruction inst = decode_s_type(instruction);
const uint32_t address = hart->regs[inst.rs1] + inst.imm;
@ -545,7 +586,7 @@ void execute(Hart* hart, uint32_t instruction)
switch (instruction & 0x7f)
{
case 0x03:
execute_op_load(hart, instruction);
execute_load(hart, instruction);
hart->pc += 4;
break;
case 0x0F:
@ -567,7 +608,7 @@ void execute(Hart* hart, uint32_t instruction)
break;
}
case 0x23:
execute_op_store(hart, instruction);
execute_store(hart, instruction);
hart->pc += 4;
break;
case 0x33:

44
emulator/hart_test.c
View File

@ -2,6 +2,7 @@
#include <inttypes.h>
#include <assert.h>
#include <stdbool.h>
#include <stdio.h>
#include "emulator/hart.h"
@ -229,7 +230,42 @@ static void test_branch()
assert(hart.pc == 124);
}
void test()
static void test_m()
{
struct Hart hart = {0};
hart.regs[1] = 0xFFFFFFFE;
hart.regs[2] = 4;
execute(&hart, 0x022081b3); // mul x3, x1, x2
assert(hart.regs[3] == 0xFFFFFFF8);
execute(&hart, 0x0220b1b3); // mulhu x3, x1, x2
assert(hart.regs[3] == 0x00000003);
execute(&hart, 0x0220a1b3); // mulhsu x3, x1, x2
assert(hart.regs[3] == 0xFFFFFFFF);
execute(&hart, 0x022091b3); // mulh x3, x1, x2
assert(hart.regs[3] == 0xFFFFFFFF);
hart.regs[1] = 0xFFFFFFFE;
hart.regs[2] = 0xFFFFFFFE;
execute(&hart, 0x022081b3); // mul x3, x1, x2
assert(hart.regs[3] == 0x00000004);
execute(&hart, 0x0220b1b3); // mulhu x3, x1, x2
assert(hart.regs[3] == 0xFFFFFFFC);
execute(&hart, 0x0220a1b3); // mulhsu x3, x1, x2
assert(hart.regs[3] == 0xFFFFFFFE);
execute(&hart, 0x022091b3); // mulh x3, x1, x2
assert(hart.regs[3] == 0x00000000);
}
int main(int argc, char* argv[])
{
test_addi();
test_slti_sltiu();
@ -240,10 +276,6 @@ void test()
test_jal();
test_jalr();
test_branch();
}
int main(int argc, char* argv[])
{
test();
test_m();
return EXIT_SUCCESS;
}