jo

WEGA/contrib/crc.c

@@ -0,0 +1,89 @@
+/* berechnet EPROM Checksummen */
+
+#include <stdio.h>
+
+static void usage(char *);
+
+int main(int argc, char **argv) {
+	char d,e,a1,a2;
+	int i,begin=0,end=-1,c;
+	FILE *f;
+	char *filename;
+
+	if(argc < 2 || argc > 4 )
+		usage(argv[0]);
+		
+	filename = argv[1];
+	
+	if(argc > 2)
+		begin = atoi(argv[2]);
+		
+	if(argc > 3)
+		end = atoi(argv[3]);
+    
+	if( end != -1 && begin > end ) {
+		fprintf(stderr, "begin adress cannot be higher than end adress\n");
+		usage(argv[0]);
+	}
+
+	if( ! ( f = fopen(filename, "rb") ) ) {
+		fprintf(stderr, "cannot open %s \n", filename);
+		usage(argv[0]);
+	}
+
+	fseek(f,begin,SEEK_SET);
+
+	d=0xff; e=0xff;
+
+	c=begin;
+
+	while(!feof(f)) {
+		if( end != -1 && c == end )
+			break;
+		else
+			c++;
+		a1 = fgetc(f);
+		if( ferror(f) ) {
+			printf("File error\n");
+			break;
+		}
+		if( feof(f) ) {
+			break;
+		}
+		a1=a1 ^ d;
+		d=a1;
+		for (i=0;i<4;i++)
+			{if ((a1 & 1)> 0)	{a1=a1 >> 1; a1=a1 | 0x80;}
+			else			{a1=a1 >> 1; a1=a1 & 0x7f;}}
+		a1=a1 & 0x0f;
+		a1=a1 ^ d;
+		d=a1;
+		for (i=0;i<3;i++)
+			{if ((a1 & 1)>0)	{a1=a1 >> 1; a1=a1 | 0x80;}
+			else			{a1=a1 >> 1; a1=a1 & 0x7f;}}
+		a2=a1;
+		a1=a1 & 0x1f;
+		a1=a1 ^ e;
+		e=a1;
+		a1=a2;
+		if ((a1 & 1)>0)	{a1=a1 >> 1; a1=a1 | 0x80;}
+			else	{a1=a1 >> 1; a1=a1 & 0x7f;}
+		a1=a1 & 0xf0;
+		a1=a1 ^ e;
+		e=a1;
+		a1=a2;
+		a1=a1 & 0xe0;
+		a1=a1 ^ d;
+		d=e;
+		e=a1;
+	} 
+	fclose(f);
+	printf ("%s %02x%02x\n","crc_checksum:",d & 0xff,e & 0xff);
+
+	return 0;
+}
+
+static void usage(char *progname) {
+	printf("usage: %s file [start adress] [end adress]\n", progname);
+	exit(1);
+}