gsslam.c

#include <stdio.h>
      #include <sys/types.h>
       #include <sys/stat.h>
       #include <fcntl.h>
  #include <unistd.h>
  #include <stdlib.h>
  

FILE* fdata;
int h;
int len;
int addr;
typedef struct seg {
	int length;
	int address;
	unsigned char* buffer;
	} seg;


void err(char* msg){
	printf("ERROR: %s",msg);
	exit(0);
}

int read3(FILE* fptr){
	char buf[3];
	int i = fread(buf,3,1,fdata);
	if(i==1)
	  return buf[0] + (buf[1]<<8) + (buf[2]<<16);
	else
	  return -1;
}

int segRead(seg* seg, FILE* fptr) {
	seg->length = read3(fptr);
	  if(seg->length <0) err("Unable to read segment length");
	if(seg->length==0) return 0;
	seg->address = read3(fptr);
	  if(seg->address <0) err("Unable to read segment addr");
	seg->buffer = malloc(seg->length);
	  if(!seg->buffer) err("Unable to allocate buffer");
  	int i = fread(seg->buffer,seg->length,1,fptr);
	  if(i != 1) err("Unable to read into buffer");
	return 1;	
}

int segWrite(seg* seg,int han){
	long i;
	i = lseek(han,seg->address,SEEK_SET);   
	  if(i != seg->address) err("Unable to seek to segment position in RAM");
	i = write(han,seg->buffer,seg->length);
	  if(i != seg->length) err("Unable to write segment to RAM");
	return seg->length;
}

void segFree(seg* seg){
	free(seg->buffer);
}

void segPrint(seg* seg){
	printf("$%06X: $%06X bytes",seg->address,seg->length);
}

unsigned main(int argc,char**argv) {
	int i;
	if(argc != 3) {
		printf(
"Usage: gsslam <filename> <ramfile>\n\n"\
  "Slam a 'nonlinear' format file generated by 64TASS 65c816 assembler\n"\
  "into a modified GSplus emulator's RAM backing file <ramfile>\n"\
  "Nonlinear files consist of segments.  Each starts with a header\n"\
  "containing a 3-byte size and a 3-byte address, followed by data.\n");
  		exit(0);
  		}
	// Read the head, and unpack 3-byte length and address fields
	fdata = fopen(argv[1],"rb");
	  if(!fdata) err("Unable to open binary file");
	// open RAM and write data
	h = open(argv[2],O_RDWR);
	if(h==-1) err("unable to open RAM");

	seg seg;
	while(i=segRead(&seg,fdata)){
	  i=segWrite(&seg,h);
	  segPrint(&seg);
	  segFree(&seg);
	  printf("\n");
	}
	close(h);
	fclose(fdata);
/*	
	
	
	
printf("opened RAM.bin: %x\n",h);
	pos = lseek(h,0x5BC,SEEK_SET);   
printf("seek: %x\n",pos);
	pos = write(h,&q,1);
printf("wrote: %x\n",pos);
	fsync(h);
	
	close(h);
	
*/

	return 0;
}