1 files changed, 10 insertions, 1 deletions
diff --git a/src/tools/mkgenome.c b/src/tools/mkgenome.c
index bb2e787..3bf1533 100644
--- a/src/tools/mkgenome.c
+++ b/src/tools/mkgenome.c
@@ -2,13 +2,22 @@
    src/tools/build.zc) into genome.h */
 #include <stdio.h>
 #include <stdint.h>
+#include <string.h>
 #ifdef _WIN32
 #include <fcntl.h>
 #include <io.h>
 #endif
 #include "memmap.h"
-int main(void)
+int main(int argc, char **argv)
 {
+	if (argc == 2 && (!strcmp(argv[1], "--help") || !strcmp(argv[1], "-h"))) {
+		fputs("usage: mkgenome [--help|-h] < image.bin > genome.h\n"
+		      "converts little-endian 64-bit image words into a c genome header.\n"
+		      "the image must match the memory layout selected when mkgenome is built.\n"
+		      "options:\n  --help, -h  show this help and exit\n", stdout);
+		return 0;
+	}
+	if (argc != 1) { fputs("mkgenome: unexpected arguments; use --help for usage\n", stderr); return 2; }
 #ifdef _WIN32
 	_setmode(_fileno(stdin), _O_BINARY);
 	_setmode(_fileno(stdout), _O_BINARY);