From: barrett@astro.cs.umass.edu (Daniel Barrett)
Subject: Re: Wanted: Code to header to DX7 4096 Byte Dumps
Date: 14 Jan 93 18:36:21 GMT

In article <1993Jan14.113207.8916@tpl68k0.tplrd.tpl.oz.au> markb@tplrd.tpl.oz.au (Mark Bower) writes:
>Does anyone have any program code (amiga or generic C) to add sysex
>bytes and checksums to yamaha DX7 4096 byte patch dumps ? I've got
>heaps of patches in this format....

	Let me guess... you got them from ucsd.edu, right? :-)  Here is
some pseudocode that shows you how to do it.

	BTW, I have a compiled program that works for these particular
patches, using similar code.  Mail me if you want a copy.  It is a real
hack, not robust at all, but it works.  It's been sitting in a directory
for years, unused, so it's not been tested on accelerated machines nor
under 2.0, but I strongly suspect it works.

                                                        Dan

 //////////////////////////////////////\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
| Dan Barrett -- Dept of Computer Science, Lederle Graduate Research Center |
| University of Massachusetts, Amherst, MA  01003  --  barrett@cs.umass.edu |
 \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\/////////////////////////////////////
------------8<----------------- cut here ----------------8<------------------
/* Here's a little program to take a DX7 patch file whose header and checksum
 * have been stripped off, and replace them.
 *
 * This program has NOT been tested extensively and is NOT robust.
 * It works ONLY if the original file size is 4096 bytes.
 * It is specifically written for files in the ucsd.edu DX7 patch archive.
 *
 * You might need to change the "r" and "w" in the fopen() calls in AddIt()
 * to "rb" and "wb" for computers (like the IBM PC) that need special
 * handling for binary vs. text files.
 *
 * Dan Barrett, barrett@cs.umass.edu, Public Domain.
 *
 * Usage:  addit oldfile newfile
 */

#include <stdio.h>

typedef unsigned char UBYTE;
 
#define DX_FILESIZE	4096L	/* Size of the patch file. */
#define	EOX		0xF7	/* End of system exclusive. */
#define HEADER_SIZE	6	/* Size of system exclusive header. */

UBYTE header[HEADER_SIZE] = { 0xF0, 67, 0, 9, 16, 0 };

UBYTE MakeChecksum();
void AddIt(), Update();

	
main(argc,argv)
int argc; char *argv[];
{
	if (argc != 3)
	{
		fprintf(stderr, "Syntax:  %s oldfile newfile\n", argv[0]);
		exit(1);
	}
	else
		AddIt(argv[1], argv[2]);

	exit(0);
}

	
UBYTE MakeChecksum(patchData)
/* Given your array of patch data, compute and return the checksum. */
UBYTE patchData[];
{
	UBYTE sum;
	int i;

	sum = 0;
	for (i=0; i<DX_FILESIZE; i++)
		sum = (sum + patchData[i]) % (1 << 8);
	return((UBYTE)((1 << 8) - sum));
}


void AddIt(oldfilename, newfilename)
char *oldfilename, *newfilename;
{
	FILE *old, *new;

	if ((old = fopen(oldfilename, "r")) == NULL)
	{
		fprintf(stderr, "Cannot open %s\n", oldfilename);
		exit(1);
	}
	else if ((new = fopen(newfilename, "w")) == NULL)
	{
		fprintf(stderr, "Cannot write %s\n", newfilename);
		fclose(old);
		exit(1);
	}
	else
	{
		Update(old, new);
		fclose(new);
		fclose(old);
	}
}


void Update(old, new)
FILE *old, *new;
{
	int i, c;
	UBYTE data[DX_FILESIZE];

	for (i=0; i<HEADER_SIZE; i++)	/* Write header to newfile. */
		putc(header[i], new);

	i = 0;
	while ((c = getc(old)) != EOF)	/* Copy old file to new. */
	{
		data[i++] = (UBYTE)c;
		putc(c, new);
	}

	putc(MakeChecksum(data), new);
	putc((UBYTE)EOX, new);
}

From: ee154fbk@sdcc15.ucsd.edu (MC)
Subject: Re: DX7 patch transfer problems...
Date: 24 Jan 93 10:45:14 GMT



After hours of grief and sweaty freak-outs I finally figured this
one out.  The source code posted by someone to ad the header and
checksum for the ucsd.edu DX7 patches was not correct.  I looked in
the manual for my TX216 and there it was, it should be 32 and NOT
16.

Otherwise the previous code works fine now for adding headers and
the rest.  Finaslly get to check out those thousands of patches at
ucsd.edu.

mc