Add support for realtime clock (#889)

Author: mpharoah

Makefile

@@ -384,7 +384,7 @@ ACTOR_DIR      := actors
 LEVEL_DIRS     := $(patsubst levels/%,%,$(dir $(wildcard levels/*/header.h)))
 
 # Directories containing source files
-SRC_DIRS += src src/boot src/game src/engine src/audio src/menu src/buffers actors levels bin data assets asm lib sound
+SRC_DIRS += src src/boot src/game src/engine src/audio src/menu src/buffers lib/librtc actors levels bin data assets asm lib sound
 LIBZ_SRC_DIRS := src/libz
 GODDARD_SRC_DIRS := src/goddard src/goddard/dynlists
 BIN_DIRS := bin bin/$(VERSION)

asm/rom_header.s

@@ -22,7 +22,7 @@
 .word  0x00000000               /* Unknown */
 #endif
 .word  0x0000004E               /* Cartridge */
-#if defined(EEP4K) && !defined(EMU_DEFAULT_TO_GCN)
+#if defined(EEP4K) && !defined(EMU_DEFAULT_TO_GCN) && !defined(USE_RTC)
 .ascii "SM"                     /* Cartridge ID */
 #else
 .ascii "ED"                     /* Cartridge ID */
@@ -35,14 +35,21 @@
     .ascii "E"                  /* NTSC-U (North America) */
 #endif
 
+#if defined(USE_RTC)
+    #define RTC_BIT 0x1
+#else
+    #define RTC_BIT 0x0
+#endif
+
+/* Savetype, region, and RTC */
 #if defined(SRAM)
-    .byte  0x32                 /* Version */
+    .byte  0x32 | RTC_BIT
 #elif defined(EEP16K)
-    .byte  0x22                 /* Version */
+    .byte  0x22 | RTC_BIT
 #elif defined(SRAM768K)
-    .byte  0x42                 /* Version */
+    .byte  0x42 | RTC_BIT
 #elif defined(FLASHRAM)
-    .byte  0x52                 /* Version */
+    .byte  0x52 | RTC_BIT
 #else
-    .byte  0x12                 /* Version */
+    .byte  0x12 | RTC_BIT
 #endif

include/config/config_rom.h

@@ -10,6 +10,12 @@
  */
 #define INTERNAL_ROM_NAME "HackerSM64          "
 
+/**
+ * Enable the realtime clock (RTC)
+ * See lib/librtc/librtc.h for RTC related functions
+ */
+// #define USE_RTC
+
 /**
  * Force the game to delete any existing save data originating from a different hack. This requires INTERNAL_ROM_NAME to be unique to work properly.
  * It is recommended to enable this if any significant changes to the save file are made that could cause issues with this or other hacks.