add a default initial program

This initial program will simply jump to the address to which the first
read file is loaded. This is what 90% of callers will probably want.

1 files changed, 27 insertions, 6 deletions

diff --git a/src/satmkboot.c b/src/satmkboot.c
index 71232dc..6abae51 100644
--- a/src/satmkboot.c
+++ b/src/satmkboot.c
@@ -76,6 +76,26 @@ static int write_output(FILE *fp)
 	return ferror(fp) ? -1 : 0;
 }
 
+static size_t default_ip(char *out)
+{
+	size_t size = 0;
+
+	out[size++] = 0xd0;                          /* mov.l addr, r0 */
+	out[size++] = 0x01;
+	out[size++] = 0x40;                          /* jmp   @r0 */
+	out[size++] = 0x2b;
+	out[size++] = 0x00;                          /* nop */
+	out[size++] = 0x09;
+	out[size++] = 0x00;                          /* nop */
+	out[size++] = 0x09;
+	out[size++] = sysid.load_addr >> 24 & 0xff;  /* addr: .long <sysid.load_addr> */
+	out[size++] = sysid.load_addr >> 16 & 0xff;
+	out[size++] = sysid.load_addr >>  8 & 0xff;
+	out[size++] = sysid.load_addr >>  0 & 0xff;
+
+	return size;
+}
+
 static size_t load_ip(char *filename, char *out, size_t maxsize)
 {
 	FILE  *fp;
@@ -131,10 +151,10 @@ static void usage(const char *progname)
 	const int width = 20;
 
 	fprintf(stderr, "usage: %s -h\n", progname);
-	fprintf(stderr, "       %s -io[prms]\n\n", progname);
+	fprintf(stderr, "       %s -o[iprms]\n\n", progname);
 	fprintf(stderr, "\t%-*s%s\n", width, "-h",              "Show this help text");
-	fprintf(stderr, "\t%-*s%s\n", width, "-i ip.bin",       "Initial program code file");
 	fprintf(stderr, "\t%-*s%s\n", width, "-o output",       "Output file");
+	fprintf(stderr, "\t%-*s%s\n", width, "-i ip.bin",       "Initial program code file");
 	fprintf(stderr, "\t%-*s%s\n", width, "-p peripherals",  "Supported peripherals (default: control pad):");
 	print_symbols(stderr, width, peripheraldefs);
 	fprintf(stderr, "\t%-*s%s\n", width, "-r regions",      "Geographical regions (default: all):");
@@ -260,7 +280,7 @@ static int process_args(int argc, char **argv)
 	} else if (!fail) {
 		if (argv[optind])
 			errors = show_arg_error(argv[0], errors, ERR_UNKNOWN_OPTION);
-		if (!ipfile || !outfile)
+		if (!outfile)
 			errors = show_arg_error(argv[0], errors, ERR_MISSING_OPTION);
 		fail = errors;
 	}
@@ -290,9 +310,10 @@ int main(int argc, char **argv)
 		if (region) ipout = serialize_region_code(ipout, region);
 	}
 
-	if ((ipsize = load_ip(ipfile, ipout, sizeof ipbuf - (ipout - ipbuf))) == -1) {
-		goto fail;
-	}
+	ipsize = ipfile
+		? load_ip(ipfile, ipout, sizeof ipbuf - (ipout - ipbuf))
+		: default_ip(ipout);
+	if (ipsize == -1) goto fail;
 	sysid.bootsize += ipsize;
 
 	if (!(outfp = fopen(outfile, "wb"))) {