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Merge pull request #1 from xamidev/assembler

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Add: PUT instruction, Assembler separation
This commit is contained in:
xamidev
2024-10-20 17:15:55 +02:00
committed by GitHub
parent 0ec13697df b19efd669a
commit c31fdb2f29
7 changed files with 306 additions and 188 deletions
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2
.gitignore vendored
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@@ -1,2 +1,4 @@
*.out *.out
dumb8 dumb8
das
*.bin

11
README.md
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@@ -6,11 +6,14 @@ This project is the implementation of a CPU in a high-level language, C. It aims
## How to test ## How to test
You can run a test program like that. I'll try making a developer's manual so one can make its own programs using the custom assembly here. You can run a test program like that. I'll try making a developer's manual so one can make its own programs using the custom assembly here.
`das` is the Dumb8 Assembler, which converts `.asm` files to `.bin` CPU executables. `dumb8` is the CPU emulator.
``` ```
make make
./dumb8 program.asm ./das program.asm
./dumb8 program.bin
``` ```
## Technical specifications ## Technical specifications
@@ -58,3 +61,7 @@ NOP
HLT HLT
``` ```
## Known bugs
- R0 is not usable (confusion with NOP opcode 0 in memory)

192
assembler/das.c Normal file
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@@ -0,0 +1,192 @@
/*
* Dumb8 code assembler
* Made by github.com/xamidev
*
* This is free and unencumbered software released into the public domain.
* For more information, please refer to <http://unlicense.org/>
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include "../cpu.h"
/*
* Reading the assembly file and writing its instructions in
* opcode format in a binary file
*/
// The code is not optimized at all. But remember: it is a DUMB assembler!
void assemble(char* filename)
{
FILE* fp = fopen(filename, "r");
if (!fp)
{
printf("Cannot read file '%s'\n", filename);
exit(1);
}
char* binary_file = strtok(filename, ".");
binary_file = strcat(binary_file, ".bin");
FILE* bin_fp = fopen(binary_file, "wb");
if (!bin_fp)
{
printf("Cannot open file '%s' for writing.\n", binary_file);
fclose(fp);
exit(1);
}
char line[256] = {0};
uint8_t buffer[BUF_MAX] = {0};
size_t i = 0;
while (fgets(line, sizeof(line), fp))
{
char instruction[10] = {0};
char reg1[10] = {0};
char reg2[10] = {0};
int addr = 0;
int value = 0;
if (strncmp(line, ";", 1) == 0)
{
continue;
}
else if (strncmp(line, "\n", 1) == 0)
{
continue;
}
else if (strncmp(line, "HLT", 3) == 0)
{
buffer[i++] = HLT;
}
else if (strncmp(line, "NOP", 3) == 0)
{
buffer[i++] = NOP;
}
else if (strncmp(line, "MOV", 3) == 0)
{
sscanf(line, "%s %[^,], %s", instruction, reg1, reg2);
int reg1_n = reg1[1] - '0';
int reg2_n = reg2[1] - '0';
buffer[i++] = MOV;
buffer[i++] = reg1_n;
buffer[i++] = reg2_n;
}
else if (strncmp(line, "ADD", 3) == 0)
{
sscanf(line, "%s %[^,], %s", instruction, reg1, reg2);
int reg1_n = reg1[1] - '0';
int reg2_n = reg2[1] - '0';
buffer[i++] = ADD;
buffer[i++] = reg1_n;
buffer[i++] = reg2_n;
}
else if (strncmp(line, "CMP", 3) == 0)
{
sscanf(line, "%s %[^,], %s", instruction, reg1, reg2);
int reg1_n = reg1[1] - '0';
int reg2_n = reg2[1] - '0';
buffer[i++] = CMP;
buffer[i++] = reg1_n;
buffer[i++] = reg2_n;
}
else if (strncmp(line, "SUB", 3) == 0)
{
sscanf(line, "%s %[^,], %s", instruction, reg1, reg2);
int reg1_n = reg1[1] - '0';
int reg2_n = reg2[1] - '0';
buffer[i++] = SUB;
buffer[i++] = reg1_n;
buffer[i++] = reg2_n;
}
else if (strncmp(line, "OR", 3) == 0)
{
sscanf(line, "%s %[^,], %s", instruction, reg1, reg2);
int reg1_n = reg1[1] - '0';
int reg2_n = reg2[1] - '0';
buffer[i++] = OR;
buffer[i++] = reg1_n;
buffer[i++] = reg2_n;
}
else if (strncmp(line, "AND", 3) == 0)
{
sscanf(line, "%s %[^,], %s", instruction, reg1, reg2);
int reg1_n = reg1[1] - '0';
int reg2_n = reg2[1] - '0';
buffer[i++] = AND;
buffer[i++] = reg1_n;
buffer[i++] = reg2_n;
}
else if (strncmp(line, "XOR", 3) == 0)
{
sscanf(line, "%s %[^,], %s", instruction, reg1, reg2);
int reg1_n = reg1[1] - '0';
int reg2_n = reg2[1] - '0';
buffer[i++] = XOR;
buffer[i++] = reg1_n;
buffer[i++] = reg2_n;
}
else if (strncmp(line, "JEQ", 3) == 0)
{
sscanf(line, "%s %[^,], %d", instruction, reg1, &addr);
int reg1_n = reg1[1] - '0';
buffer[i++] = JEQ;
buffer[i++] = reg1_n;
buffer[i++] = addr;
}
else if (strncmp(line, "JMP", 3) == 0)
{
sscanf(line, "%s %d", instruction, &addr);
buffer[i++] = JMP;
buffer[i++] = addr;
}
else if (strncmp(line, "OUT", 3) == 0)
{
sscanf(line, "%s %s", instruction, reg1);
int reg1_n = reg1[1] - '0';
buffer[i++] = OUT;
buffer[i++] = reg1_n;
}
else if (strncmp(line, "IN", 2) == 0)
{
sscanf(line, "%s %s", instruction, reg1);
int reg1_n = reg1[1] - '0';
buffer[i++] = IN;
buffer[i++] = reg1_n;
}
else if (strncmp(line, "PUT", 3) == 0)
{
sscanf(line, "%s %[^,], %d", instruction, reg1, &value);
int reg1_n = reg1[1] - '0';
buffer[i++] = PUT;
buffer[i++] = reg1_n;
buffer[i++] = value;
}
else {
printf("Unknown instruction '%s'\n", line);
}
}
fwrite(buffer, sizeof(uint8_t), i, bin_fp);
fclose(fp);
fclose(bin_fp);
}
int main(int argc, char* argv[])
{
if (argc < 2)
{
printf("Usage: %s <assembly file>\n", argv[0]);
exit(1);
}
assemble(argv[1]);
return 0;
}

209
cpu.c
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@@ -11,60 +11,7 @@
#include <stdint.h> #include <stdint.h>
#include <stdbool.h> #include <stdbool.h>
#include <string.h> #include <string.h>
#include "cpu.h"
#define MEM_SIZE 256
#define NUM_REGISTERS 4
/*
* Instruction set
* Here, we're making a RISC (reduced instruction set computer)
* so we're staying minimalistic.
*/
typedef enum
{
// 0x00 -> No operation
NOP = 0,
// 0xA? -> Memory operations
MOV = 0xA0,
// 0xB? -> Arithmetic operations
ADD = 0xB0,
SUB = 0xB1,
// 0xC? -> Bitwise operations
OR = 0xC0,
AND = 0xC1,
XOR = 0xC2,
// 0xD? -> Input/output operations
OUT = 0xD0,
IN = 0xD1,
// 0xE? -> Jump and comparisons
JMP = 0xE0,
JEQ = 0xE1,
CMP = 0xE2,
// 0xF? -> Misc operations
HLT = 0xFF
} instruction_set_t;
/*
* CPU structure definition
* Contains 4 8-bit registers, memory, a program counter, a halt switch, and flags.
*/
typedef struct
{
uint8_t reg[NUM_REGISTERS];
uint8_t memory[MEM_SIZE];
uint16_t pc;
bool halted;
bool equal_flag;
int flag_clear_delay;
} CPU_t;
CPU_t cpu; CPU_t cpu;
@@ -91,7 +38,7 @@ void cpu_init()
void cpu_exec(uint8_t opcode) void cpu_exec(uint8_t opcode)
{ {
uint8_t reg1, reg2, addr; uint8_t reg1, reg2, addr, value;
if (cpu.flag_clear_delay > 0) if (cpu.flag_clear_delay > 0)
{ {
@@ -112,6 +59,11 @@ void cpu_exec(uint8_t opcode)
reg2 = cpu.memory[cpu.pc++]; reg2 = cpu.memory[cpu.pc++];
cpu.reg[reg1] = cpu.reg[reg2]; cpu.reg[reg1] = cpu.reg[reg2];
break; break;
case PUT:
reg1 = cpu.memory[cpu.pc++];
value = cpu.memory[cpu.pc++];
cpu.reg[reg1] = value;
break;
case ADD: case ADD:
reg1 = cpu.memory[cpu.pc++]; reg1 = cpu.memory[cpu.pc++];
reg2 = cpu.memory[cpu.pc++]; reg2 = cpu.memory[cpu.pc++];
@@ -184,130 +136,32 @@ void cpu_load(const uint8_t* program, size_t size)
} }
} }
/* void load_program_from_bin(char* binary_file)
* Reading the assembly file and writing its instructions in
* opcode format in memory
*/
void assemble(const char* filename)
{ {
FILE* fp = fopen(filename, "r"); FILE* binary_fp = fopen(binary_file, "rb");
if (!fp) if (!binary_fp)
{ {
printf("Cannot read file '%s'\n", filename); printf("Cannot open file '%s' for reading.\n", binary_file);
exit(1); exit(1);
} }
char line[256] = {0}; fseek(binary_fp, 0, SEEK_END);
size_t mem_index = 0; size_t size = ftell(binary_fp);
rewind(binary_fp);
while (fgets(line, sizeof(line), fp)) uint8_t* program_buffer = (uint8_t*)malloc(size);
{ if (!program_buffer)
char instruction[10] = {0}; {
char reg1[10] = {0}; printf("Memory allocation failed\n");
char reg2[10] = {0}; fclose(binary_fp);
int addr; exit(1);
if (strncmp(line, ";", 1) == 0) }
{
// comment, ignore
continue;
}
else if (sscanf(line, "%s %[^,], %s", instruction, reg1, reg2) == 3)
{
//printf("SS1");
int reg1_n = reg1[1] - '0';
int reg2_n = reg2[1] - '0';
if (strncmp(instruction, "MOV", 3) == 0) fread(program_buffer, sizeof(uint8_t), size, binary_fp);
{ cpu_load(program_buffer, size);
cpu.memory[mem_index++] = MOV; free(program_buffer);
cpu.memory[mem_index++] = reg1_n; fclose(binary_fp);
cpu.memory[mem_index++] = reg2_n;
} else if (strncmp(instruction, "ADD", 3) == 0)
{
cpu.memory[mem_index++] = ADD;
cpu.memory[mem_index++] = reg1_n;
cpu.memory[mem_index++] = reg2_n;
} else if (strncmp(instruction, "CMP", 3) == 0)
{
cpu.memory[mem_index++] = CMP;
cpu.memory[mem_index++] = reg1_n;
cpu.memory[mem_index++] = reg2_n;
} else if (strncmp(instruction, "SUB", 3) == 0)
{
cpu.memory[mem_index++] = SUB;
cpu.memory[mem_index++] = reg1_n;
cpu.memory[mem_index++] = reg2_n;
}
else if (strncmp(instruction, "OR", 2) == 0)
{
cpu.memory[mem_index++] = OR;
cpu.memory[mem_index++] = reg1_n;
cpu.memory[mem_index++] = reg2_n;
}
else if (strncmp(instruction, "AND", 3) == 0)
{
cpu.memory[mem_index++] = AND;
cpu.memory[mem_index++] = reg1_n;
cpu.memory[mem_index++] = reg2_n;
}
else if (strncmp(instruction, "XOR", 3) == 0)
{
cpu.memory[mem_index++] = XOR;
cpu.memory[mem_index++] = reg1_n;
cpu.memory[mem_index++] = reg2_n;
}
} else if (sscanf(line, "%s %[^,], %d", instruction, reg1, &addr) == 2)
{
//printf("SS2");
int reg1_n = reg1[1] - '0';
if (strncmp(instruction, "JEQ", 3) == 0)
{
cpu.memory[mem_index++] = JEQ;
cpu.memory[mem_index++] = reg1_n;
cpu.memory[mem_index++] = addr;
}
else if (sscanf(line, "%s %d", instruction, &addr) == 2)
{
//printf("SS3");
if (strncmp(instruction, "JMP", 3) == 0)
{
cpu.memory[mem_index++] = JMP;
cpu.memory[mem_index++] = addr;
}
}
else if (sscanf(line, "%s %s", instruction, reg1) == 2)
{
//printf("SS4");
int reg1_n = reg1[1] - '0';
if (strncmp(instruction, "OUT", 3) == 0)
{
cpu.memory[mem_index++] = OUT;
cpu.memory[mem_index++] = reg1_n;
}
if (strncmp(instruction, "IN", 2) == 0)
{
cpu.memory[mem_index++] = IN;
cpu.memory[mem_index++] = reg1_n;
}
}
}
else if (strncmp(line, "HLT", 3) == 0)
{
cpu.memory[mem_index++] = HLT;
}
else if (strncmp(line, "NOP", 3) == 0)
{
cpu.memory[mem_index++] = NOP;
}
}
fclose(fp);
} }
/* /*
@@ -335,7 +189,7 @@ void cpu_dump()
for (size_t i=0; i<NUM_REGISTERS; i++) for (size_t i=0; i<NUM_REGISTERS; i++)
{ {
printf("R%d: 0x%x\n", i, cpu.reg[i]); printf("R%lu: 0x%x\n", i, cpu.reg[i]);
} }
puts(""); puts("");
} }
@@ -358,6 +212,7 @@ void mem_dump()
{ {
// Instructions (colored background) // Instructions (colored background)
case 0xa0: case 0xa0:
case 0xa1:
printf("\e[42m%02x\e[0m ", cpu.memory[i]); printf("\e[42m%02x\e[0m ", cpu.memory[i]);
break; break;
@@ -416,18 +271,14 @@ int main(int argc, char* argv[])
if (argc < 2) if (argc < 2)
{ {
printf("Usage: %s <assembly file>\n", argv[0]); printf("Usage: %s <program>\n", argv[0]);
return -1; return -1;
} }
assemble(argv[1]); load_program_from_bin(argv[1]);
// Dumping our program // Dumping our program
mem_dump(); mem_dump();
reg_write(1, 0x68);
reg_write(2, 0x69);
reg_write(3, 0x21);
cpu_run(); cpu_run();
// Post-mortem analysis // Post-mortem analysis

60
cpu.h Normal file
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@@ -0,0 +1,60 @@
#ifndef CPU_H
#define CPU_H
#define MEM_SIZE 256
#define NUM_REGISTERS 4
#define BUF_MAX 256
/*
* Instruction set
* Here, we're making a RISC (reduced instruction set computer)
* so we're staying minimalistic.
*/
typedef enum
{
// 0x00 -> No operation
NOP = 0,
// 0xA? -> Memory operations
MOV = 0xA0,
PUT = 0xA1,
// 0xB? -> Arithmetic operations
ADD = 0xB0,
SUB = 0xB1,
// 0xC? -> Bitwise operations
OR = 0xC0,
AND = 0xC1,
XOR = 0xC2,
// 0xD? -> Input/output operations
OUT = 0xD0,
IN = 0xD1,
// 0xE? -> Jump and comparisons
JMP = 0xE0,
JEQ = 0xE1,
CMP = 0xE2,
// 0xF? -> Misc operations
HLT = 0xFF
} instruction_set_t;
/*
* CPU structure definition
* Contains 4 8-bit registers, memory, a program counter, a halt switch, and flags.
*/
typedef struct
{
uint8_t reg[NUM_REGISTERS];
uint8_t memory[MEM_SIZE];
uint16_t pc;
bool halted;
bool equal_flag;
int flag_clear_delay;
} CPU_t;
#endif

12
makefile
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@@ -1,5 +1,11 @@
all: CC=gcc
gcc -g *.c -o dumb8 CFLAGS=-g -Wall -Wextra
all: asm
$(CC) *.c $(CFLAGS) -o dumb8
asm:
$(CC) assembler/*.c $(CFLAGS) -o das
clean: clean:
rm a.out rm dumb8 das

8
program.asm
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@@ -1,7 +1,7 @@
;this is a comment ;this is a comment
PUT R2, 5
MOV R1, R2
ADD R1, R2
OUT R1
OUT R2
OUT R3
IN R0
HLT HLT