/*
 * file.c
 * $Id: file.c,v 1.4 2005/01/12 19:25:58 mah Exp $
 * Christoph Berg <cb@cs.uni-sb.de>
 *
 * 010814
 */

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

#include "help.h"
#include "dlx.h"

#define LINE_LEN 1024

int load_file(char *fname) {
    FILE *file;
    char line[LINE_LEN];
    int lineno = 0;
    int adr, d[4];
    int nbytes, copybase, i;

    if ((file = fopen(fname, "rt")) == NULL) {
        perror(fname);
        exit(1);
    }

    lineno++;
    if(fgets(line, LINE_LEN, file) == NULL) {
        perror("fgets");
        exit(1);
    }

    if(sscanf(line, "start:%x %x %x %x %x %x\n", &(state.start),
              &(state.maxaddr) , &(state.text),
              &(state.textsize), &(state.data),
              &(state.datasize)) != 6) {
        die("Error while parsing %s line %u: \n%s", fname, lineno, line);
    }

    adr = -1; // requires address field in object file

    while(fgets(line, LINE_LEN, file) != NULL) {
        lineno++;
        //printf("line %d: %s", lineno, line);
        if((nbytes = sscanf(line, "%x:%02x%02x%02x%02x\n", &adr, d+3, d+2, d+1, d) - 1) >= 1) { // -1 because of address field
            //printf("read %x : %x %x %x %x\n", adr, d[3], d[2], d[1], d[0]);
            if(adr < 0 || adr >= state.memorysize)
                die("%s line %u: no memory allocated at address %x", fname, lineno, adr);
            copybase = 4-nbytes; // copy the *upper* entries of d
            for(i = copybase; i < 4; i++)
                state.memory[adr-copybase+i] = d[i];
            adr += nbytes; // increase address
        } else if((nbytes = sscanf(line, ":%02x%02x%02x%02x\n", d+3, d+2, d+1, d)) >= 1) {
            //printf("read (%x): %x %x %x %x\n", adr, d[3], d[2], d[1], d[0]);
            if(adr < 0 || adr >= state.memorysize)
                die("%s line %u: no memory allocated at address %x", fname, lineno, adr);
            copybase = 4-nbytes; // copy the *upper* entries of d
            for(i = copybase; i < 4; i++)
                state.memory[adr-copybase+i] = d[i];
            adr += nbytes; // increase address
        } else {
            die("Error while parsing %s line %u: \n%s", fname, lineno, line);
        }
    }
    fclose(file);

    state.dpc = state.start;
    state.pc = state.dpc + 4;
    state.stack = state.memorysize;
    state.gpr[STACK_R] = state.stack;

    printf("loaded %s (%d lines)\n", fname, lineno);
    printf("start: 0x%x, maximum address: 0x%x\n", state.start, state.maxaddr);
    printf("text: 0x%x, 0x%x bytes\n", state.text, state.textsize);
    printf("data: 0x%x, 0x%x bytes\n", state.data, state.datasize);
    printf("stack allocated at 0x%x\n", state.stack);
    return 0;
}