Message Integrity Checking

[uccvend-snackrom.git] / ROM2 / helpers.c

diff --git a/ROM2/helpers.c b/ROM2/helpers.c
index f336ae1..f7bb406 100644 (file)
--- a/ROM2/helpers.c
+++ b/ROM2/helpers.c
@@ -61,3 +61,29 @@ void my_memset(char* dst, u8 val, u16 count) {
        char* c;
        for (c = dst; c < dst+count; c++) *c = val;
 }
+
+u8 hexchar2u8(char b) {
+       if (b >= '0' && b <= '9') return b-'0';
+       if (b >= 'a' && b <= 'f') return b-'a'+0x0a;
+       if (b >= 'A' && b <= 'F') return b-'A'+0x0a;
+       return 0;
+}
+
+char nibble2hexchar(u8 b) {
+       if (b <= 9) return b+'0';
+       if (b >= 10 && b <= 15) return b+'A'-10;
+       return 'X';
+}
+
+u8 hex2u8(char msb, char lsb) {
+       return (hexchar2u8(msb) << 4) + hexchar2u8(lsb);
+}
+
+static char hexconv_buf[3];
+char* u82hex(u8 a) {
+       hexconv_buf[0] = nibble2hexchar((a&0xf0) >> 4);
+       hexconv_buf[1] = nibble2hexchar(a&0x0f);
+       hexconv_buf[2] = '\0';
+       return hexconv_buf;
+}
+