minimig_hdd: cleanup and refactoring.

minimig_hdd.h

@@ -6,8 +6,8 @@
 #include "minimig_hdd_internal.h"
 
 // functions
-void HandleHDD(unsigned char c1, unsigned char c2);
-unsigned char OpenHardfile(unsigned char unit);
+void HandleHDD(uint8_t c1, uint8_t c2);
+uint8_t OpenHardfile(uint8_t unit);
 int checkHDF(const char* name, struct RigidDiskBlock **rdb);
 
 #endif // __HDD_H__

minimig_hdd_internal.h

@@ -5,6 +5,8 @@
 // For hardfiles that have no RDB information, we'll just create a single-partition RDB and Part block
 // on blocks 0 and 1.  All other blocks within the first cylinder will be translated into the hardfile
 
+#define RDB_MAGIC 0x4B534452 // "RDSK"
+
 struct RigidDiskBlock {
 	unsigned long   rdb_ID;	// "RDSK"
 	unsigned long   rdb_Summedlongs; // 0x40