Muri: An Alternative Assembler for Nga

muri.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#define KiB * 1024
#define MAX_NAMES 1024
#define STRING_LEN 64

int32_t target[128 KiB];
int32_t here;
char    Labels[MAX_NAMES][STRING_LEN];
int32_t Pointers[MAX_NAMES];
int32_t np;

void save() {
  FILE *fp;

  if ((fp = fopen("muri.image", "wb")) == NULL) {
    printf("Unable to save the image!\n");
    exit(2);
  }

  fwrite(&target, sizeof(int32_t), here, fp);
  fclose(fp);
}

int32_t lookup(char *name) {
  int32_t slice = -1;
  int32_t n = np;
  while (n > 0) {
    n--;
    if (strcmp(Labels[n], name) == 0)
      slice = Pointers[n];
  }
  return slice;
}

void add_label(char *name, int32_t slice) {
  if (lookup(name) == -1) {
    strcpy(Labels[np], name);
    Pointers[np] = slice;
    np++;
  } else {
    printf("Fatal error: %s already defined\n", name);
    exit(0);
  }
}

void read_line(FILE *file, char *line_buffer) {
  if (file == NULL || line_buffer == NULL)
  {
    printf("Error: file or line buffer pointer is null.");
    exit(1);
  }
  int ch = getc(file);
  int count = 0;
  while ((ch != '\n') && (ch != EOF)) {
    line_buffer[count] = ch;
    count++;
    ch = getc(file);
  }
  line_buffer[count] = '\0';
}

char source[16 KiB];

int32_t opcode_for(char *s) {
  if (strcmp(s, "..") == 0) return 0;  if (strcmp(s, "li") == 0) return 1;
  if (strcmp(s, "du") == 0) return 2;  if (strcmp(s, "dr") == 0) return 3;
  if (strcmp(s, "sw") == 0) return 4;  if (strcmp(s, "pu") == 0) return 5;
  if (strcmp(s, "po") == 0) return 6;  if (strcmp(s, "ju") == 0) return 7;
  if (strcmp(s, "ca") == 0) return 8;  if (strcmp(s, "cc") == 0) return 9;
  if (strcmp(s, "re") == 0) return 10; if (strcmp(s, "eq") == 0) return 11;
  if (strcmp(s, "ne") == 0) return 12; if (strcmp(s, "lt") == 0) return 13;
  if (strcmp(s, "gt") == 0) return 14; if (strcmp(s, "fe") == 0) return 15;
  if (strcmp(s, "st") == 0) return 16; if (strcmp(s, "ad") == 0) return 17;
  if (strcmp(s, "su") == 0) return 18; if (strcmp(s, "mu") == 0) return 19;
  if (strcmp(s, "di") == 0) return 20; if (strcmp(s, "an") == 0) return 21;
  if (strcmp(s, "or") == 0) return 22; if (strcmp(s, "xo") == 0) return 23;
  if (strcmp(s, "sh") == 0) return 24; if (strcmp(s, "zr") == 0) return 25;
  if (strcmp(s, "en") == 0) return 26;
  return 0;
}

void pass1(char *fname) {
  char *buffer = (char *)source;
  char command;
  unsigned int opcode;
  char inst[3];
  inst[2] = '\0';
  FILE *fp;
  here = 0;
  fp = fopen(fname, "r");
  if (fp == NULL)
    return;
  while (!feof(fp)) {
    read_line(fp, buffer);
    if (buffer[1] != '\t') {
      printf("ERROR: Invalid line\n");
      exit(2);
    }
    command = buffer[0];
    opcode = 0;
    switch (command) {
      case 'i': memcpy(inst, buffer + 8, 2);
                opcode = opcode_for(inst);
                opcode = opcode << 8;
                memcpy(inst, buffer + 6, 2);
                opcode += opcode_for(inst);
                opcode = opcode << 8;
                memcpy(inst, buffer + 4, 2);
                opcode += opcode_for(inst);
                opcode = opcode << 8;
                memcpy(inst, buffer + 2, 2);
                opcode += opcode_for(inst);
                target[here++] = opcode;
                break;
      case 'r': target[here++] = 9999;
                break;
      case 'd': target[here++] = atoi(buffer+2);
                break;
      case 'c': target[here++] = buffer[2];
                break;
      case 's': printf("String\n");
                break;
      case ':': add_label(buffer+2, here);
                break;
    }
  }
  fclose(fp);
}

void pass2(char *fname) {
  char *buffer = (char *)source;
  char command;
  FILE *fp;
  here = 0;
  fp = fopen(fname, "r");
  if (fp == NULL)
    return;
  while (!feof(fp)) {
    read_line(fp, buffer);
    if (buffer[1] != '\t') {
      printf("ERROR: Invalid line\n");
      exit(2);
    }
    command = buffer[0];
    switch (command) {
      case 'i': here++;
                break;
      case 'r': target[here++] = lookup(buffer+2);
                break;
      case 'd': here++;
                break;
      case 'c': here++;
                break;
      case 's': break;
      case ':': break;
    }
  }
  fclose(fp);
}

int main(int argc, char **argv) {
  np = 0;
  int i = 1;
  if (argc > 1) {
    pass1(argv[1]);
    pass2(argv[1]);
    for(int i = 0; i < here; i++)
      printf("%d,", target[i]);
    printf("\n");
    for(int i = 0; i < np; i++)
      printf("%s,", Labels[i]);
    printf("\n");
    save();
  }
  else
    printf("muri\n(c) 2017 charles childers\n\nTry:\n  %s filename\n", argv[0]);
  return 0;
}