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asm.c
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asm.c
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#include "common.h"
unsigned short offset = 0;
unsigned short pc = 0;
unsigned short memory[256];
unsigned short registers[16];
const char* DELIM = " \n\r\t,";
int is_hex_digit(char c) {
return (c >= '0' && c <= '9') || (c >= 'a' && c <= 'f') || (c >= 'A' && c <= 'F');
}
int hex_digit_to_i(char c) {
if(c >= '0' && c <= '9')
return c - '0';
if(c >= 'a' && c <= 'f')
return c - 'a' + 10;
if(c >= 'A' && c <= 'F')
return c - 'A' + 10;
return 0;
}
enum {
TYPE_IMMEDIATE,
TYPE_IMMEDIATE_MEMORY,
TYPE_REGISTER_MEMORY,
TYPE_REGISTER
};
typedef struct {
int type; // 0 = immediate, 1 = immediate memory, 2 = register memory, 3 = register
unsigned short value;
} argument;
int parse_arguments(argument* list) {
for(int i = 0; i < 3; ++i) {
char* v1 = strtok(NULL, DELIM);
if(!v1) {
return i;
}
int ismem = 0;
if(*v1 == '[') {
ismem = 1;
v1++;
}
if(*v1 == 'r') {
if(!is_hex_digit(v1[1])) {
printf("Expected hex digit after 'r'\n"); return -1;
}
list[i].value = hex_digit_to_i(v1[1]);
list[i].type = ismem ? 2 : 3;
} else {
unsigned short value;
sscanf(v1, "%hx", &value);
list[i].value = value;
list[i].type = ismem ? 1 : 0;
}
}
return 3;
}
unsigned short make_reg_inst(int opcode, int d, int s, int t) {
return ((opcode & 0xF) << 12)
| ((d & 0xF) << 8)
| ((s & 0xF) << 4)
| ((t & 0xF) << 0);
}
unsigned short make_addr_inst(int opcode, int d, int addr) {
return ((opcode & 0xF) << 12)
| ((d & 0xF) << 8)
| ((addr & 0xFff) << 0);
}
void set_reg_inst(int opcode, int d, int s, int t) {
memory[offset++] = make_reg_inst(opcode, d, s, t);
}
void set_addr_inst(int opcode, int d, int addr) {
memory[offset++] = make_addr_inst(opcode, d, addr);
}
void set_imm(unsigned short value) {
memory[offset++] = value;
}
int main(int argc, char* argv[]) {
if(argc != 2) {
printf("Usage: ./asm <filename>\n");
return 1;
}
FILE* f = fopen(argv[1], "r");
if(!f) {
printf("Could not open '%s'\n", argv[1]);
return 1;
}
char* line = NULL; size_t size = 0;
int linecount = 0;
while(getline(&line, &size, f) >= 0) {
linecount++;
char* tok = strtok(line, DELIM);
if(!tok || !*tok || *tok == ';') continue;
if(*tok == '.') {
if(streq(tok, ".offset")) {
char* v1 = strtok(NULL, DELIM);
if(!v1) {
//TODO error handling
}
sscanf(v1, "%hx", &offset);
} else if(streq(tok, ".pc")) {
char* v1 = strtok(NULL, DELIM);
if(!v1) {
//TODO error handling
}
sscanf(v1, "%hx", &pc);
} else if(tok[1] == 'r' && is_hex_digit(tok[2]) && tok[3] == 0) {
char* v1 = strtok(NULL, DELIM);
unsigned short value;
sscanf(v1, "%hx", &value);
unsigned char r = hex_digit_to_i(tok[2]);
registers[r] = value;
} else if(streq(tok, ".immediate")) {
char* v1;
while(v1 = strtok(NULL, DELIM)) {
unsigned short value;
sscanf(v1, "%hx", &value);
set_imm(value);
}
} else {
printf("Error: Unknown token '%s'\n", tok);
return 1;
}
continue;
}
argument args[3];
int num = parse_arguments(args);
if(num == -1) {
printf("Error parsing arguments\n");
return 1;
}
#define REQUIRES(c, err) if(!(c)) {printf("ERROR: " err " on line %d\n", linecount); return 1; }
#define ARITH_INST(i, n) else if(streq(tok, n)) { REQUIRES(num == 3 && args[0].type == TYPE_REGISTER && args[1].type == TYPE_REGISTER && args[2].type == TYPE_REGISTER, n " requires three register operands"); set_reg_inst(i, args[0].value, args[1].value, args[2].value); }
if(streq(tok, "hlt")) {
set_reg_inst(0, 0, 0, 0);
}
ARITH_INST(1, "add")
ARITH_INST(2, "sub")
ARITH_INST(3, "and")
ARITH_INST(4, "xor")
ARITH_INST(5, "shl")
ARITH_INST(6, "shr")
else if(streq(tok, "mov")) {
REQUIRES(num == 2, "mov requires exactly two arguments");
REQUIRES(args[0].type != TYPE_IMMEDIATE, "destination to mov cannot be immediate value");
if(args[0].type == TYPE_IMMEDIATE_MEMORY || args[0].type == TYPE_REGISTER_MEMORY) {
REQUIRES(args[1].type == TYPE_REGISTER, "mov requires one register argument");
if(args[0].type == TYPE_IMMEDIATE_MEMORY) {
set_addr_inst(9, args[1].value, args[0].value);
} else {
set_reg_inst(11, args[1].value, 0, args[0].value);
}
} else {
REQUIRES(args[1].value != TYPE_REGISTER, "cannot move from register to register");
if(args[1].type == TYPE_IMMEDIATE) {
set_addr_inst(7, args[0].value, args[1].value);
} else if(args[1].type == TYPE_IMMEDIATE_MEMORY) {
set_addr_inst(8, args[0].value, args[1].value);
} else {
set_reg_inst(10, args[0].value, 0, args[1].value);
}
}
}
else if(streq(tok, "load")) {
REQUIRES(num == 2 && args[0].type == TYPE_REGISTER && args[1].type == TYPE_IMMEDIATE_MEMORY, "load requires one register and one immediate memory argument");
set_addr_inst(8, args[0].value, args[1].value);
}
else if(streq(tok, "store")) {
REQUIRES(num == 2 && args[0].type == TYPE_IMMEDIATE_MEMORY && args[1].type == TYPE_REGISTER, "store requires one immediate memory and one register argument");
set_addr_inst(9, args[1].value, args[0].value);
}
else if(streq(tok, "loadi")) {
REQUIRES(num == 2 && args[0].type == TYPE_REGISTER && args[1].type == TYPE_REGISTER_MEMORY, "loadi requires one register and one register memory argument");
set_addr_inst(10, args[0].value, args[1].value);
}
else if(streq(tok, "storei")) {
REQUIRES(num == 2 && args[0].type == TYPE_REGISTER_MEMORY && args[1].type == TYPE_REGISTER, "storei requires one register memory and one register argument");
set_addr_inst(11, args[1].value, args[0].value);
}
else if(streq(tok, "brz")) {
REQUIRES(num == 2 && args[0].type == TYPE_REGISTER && args[1].type == TYPE_IMMEDIATE, "brz requires one register and one immediate argument");
set_addr_inst(12, args[0].value, args[1].value);
}
else if(streq(tok, "brp")) {
REQUIRES(num == 2 && args[0].type == TYPE_REGISTER && args[1].type == TYPE_IMMEDIATE, "brz requires one register and one immediate argument");
set_addr_inst(13, args[0].value, args[1].value);
}
else if(streq(tok, "jmp")) {
REQUIRES(num == 1 && args[0].type == TYPE_REGISTER, "jmp requires one register argument");
set_reg_inst(14, args[0].value, 0, 0);
}
else if(streq(tok, "call")) {
REQUIRES(num == 2 && args[0].type == TYPE_REGISTER && args[1].type == TYPE_IMMEDIATE, "call requires one register and one immediate argument");
set_addr_inst(15, args[0].value, args[1].value);
}
else {
printf("Unknown instruction '%s'\n", tok);
return 1;
}
}
const char* fn = strtok(argv[1], ".");
if(!fn) fn = "out";
char buffer[128];
sprintf(buffer, "%s.toy", fn);
FILE* out = fopen(buffer, "wb");
if(!out) {
printf("Error: Could not open '%s' for writing\n", buffer);
return 1;
}
fwrite(&pc, sizeof(pc), 1, out);
fwrite(®isters, sizeof(registers), 1, out);
fwrite(&memory, sizeof(memory), 1, out);
fclose(out);
printf("Output written to '%s'\n", buffer);
}