tools: add byteswap

.gitignore

@@ -8,3 +8,4 @@ build/*
 tools/bin2hex
 tools/flterm
 tools/mkmmimg
+tools/byteswap

tools/Makefile

@@ -1,5 +1,5 @@
-TARGETS=mkmmimg flterm
-CC=clang
+TARGETS=mkmmimg flterm byteswap
+CC=gcc
 
 all: $(TARGETS)
 

tools/byteswap.c

@@ -0,0 +1,60 @@
+/*
+ * Milkymist SoC
+ * Copyright (C) 2007, 2008, 2009, 2010 Sebastien Bourdeauducq
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+int main(int argc, char *argv[])
+{
+	FILE *fdi, *fdo;
+	unsigned short wi;
+	unsigned short wo;
+	int i;
+	
+	if(argc != 3) {
+		fprintf(stderr, "Usage: byteswap <infile> <outfile>\n");
+		return 1;
+	}
+	fdi = fopen(argv[1], "rb");
+	if(!fdi) {
+		perror("Unable to open input file");
+		return 1;
+	}
+	fdo = fopen(argv[2], "w");
+	if(!fdo) {
+		perror("Unable to open output file");
+		fclose(fdi);
+		return 1;
+	}
+	while(1) {
+		if(fread(&wi, 2, 1, fdi) <= 0) break;
+		wo = 0;
+		for(i=0;i<16;i++)
+			if(wi & (1 << i))
+				wo |= (0x8000 >> i);
+		/* comment out the next line on big endian machines! */
+		wo = ((wo & 0x00ff) << 8) | ((wo & 0xff00) >> 8);
+		fwrite(&wo, 2, 1, fdo);
+	}
+	fclose(fdi);
+	if(fclose(fdo) != 0) {
+		perror("Unable to close output file");
+		return 1;
+	}
+	return 0;
+}