1 files changed, 38 insertions, 0 deletions
diff --git a/source/patch.c b/source/patch.c
new file mode 100644
index 0000000..78d2531
--- /dev/null
+++ b/source/patch.c
@@ -0,0 +1,38 @@
+/*
+	Copyright 2022-2023 Gabriel Bjørnager Jensen.
+
+	This file is part of agbsum.
+
+	agbsum is free software: you can redistribute it
+	and/or modify it under the terms of the GNU
+	Affero General Public License as published by
+	the Free Software Foundation, either version 3
+	of the License, or (at your option) any later
+	version.
+
+	agbsum 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 Affero General Public License for more
+	details.
+
+	You should have received a copy of the GNU
+	Affero General Public License along with agbsum.
+	If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <agbsum.h>
+
+#include <stdio.h>
+
+void
+agb_patch (FILE* const restrict image, char unsigned sum)
+{
+	fseek (image, (long)(agb_sumDataStart + agb_sumOffset), SEEK_SET);
+
+	if (fwrite (&sum, 0x1u, 0x1u, image) != 0x1u) {
+		fputs ("Unable to patch ROM\n", stderr);
+		agb_exit (agb_Cnd_Error, image);
+	}
+}