feat(buzbee): add command hashing mode

bbhashtool.c

@@ -0,0 +1,38 @@
+/* Generates "hashes" from ASCII strings to be used in BUZBEE */
+
+#include <stdint.h>
+#include <stdio.h>
+
+const int CCH_CMD = 4;
+
+int mkhash(const char pszCmd[]);
+
+int main(void) {
+	/* Add your commands here to be hashed. Imprtant that they all be CCH_CMD
+	 * chars long EXCLUDING the NUL terminator. */
+	char *ppszCmds[] = {
+		"CALL",
+		"EXEC",
+		"HELP",
+		"PEEK",
+		"POKE",
+		"SREC",
+		/* "BOOT", */
+	};
+
+	for (int iCmd = 0; iCmd < (sizeof(ppszCmds) / sizeof(char *)); iCmd++)
+		printf("BBC%s\n  fcb $%.2X\n", ppszCmds[iCmd], mkhash(ppszCmds[iCmd]));
+
+	return 0;
+}
+
+int mkhash(const char pszCmd[]) {
+	uint8_t nhash = 0;
+
+	/* NOTE: Very important that condition is the length of the string MINUS the
+	 * NUL terminator, in this case iChar < 4 */
+	for (int iChar = 0; iChar < CCH_CMD; iChar++)
+		nhash = nhash - pszCmd[iChar];
+
+	return nhash;
+}