From: Lukas Krickl <lukas@krickl.dev>
Date: Sun, 17 Nov 2024 05:45:02 +0000 (+0100)
Subject: WIP: mbc1 ram access
X-Git-Url: https://git.krickl.dev/?a=commitdiff_plain;h=cb7ccdefcb7e86fad3db0a616165ba02f2fdac66;p=gbrg%2F.git

WIP: mbc1 ram access
---

diff --git a/src/header.inc b/src/header.inc
index 69696a4..14bb7a3 100644
--- a/src/header.inc
+++ b/src/header.inc
@@ -12,7 +12,11 @@ logo_end:
 
 ; cartride type
 ; MBC1+RAM+Battery
-.db 0x02 
-.fill 0, 0x14D - $
+.db 0x03
+  ; rom size 32K
+.db 0x00
+  ; ram size 8k
+.db 0x02
+.fill 0, 0x14B - $
 .chksm
 .fill 0, 0x150 - $
diff --git a/src/hw.inc b/src/hw.inc
index b44febb..9c796c5 100644
--- a/src/hw.inc
+++ b/src/hw.inc
@@ -88,6 +88,6 @@
 ; MBC1 registers
 
 ; write 0xA here to enable sram 
-#define SRAM_ENABLE 0x0000
-#define ROM_BANKSEL 0x2000
-#define SRAM_BANKSEL 0x4000
+#define MBC1_SRAM_ENABLE 0x0000
+#define MBC1_ROM_BANKSEL 0x2000
+#define MBC1_SRAM_BANKSEL 0x4000
diff --git a/src/map.s b/src/map.s
index db49b0a..8d25df4 100644
--- a/src/map.s
+++ b/src/map.s
@@ -28,9 +28,10 @@
 
 
   ; maps: 
-  ;   a map is a collection of room struct pointers
+  ;   a map is a collection of room structs
   ;   of n*m rooms. when a player leaves a room 
   ;   they will transition to the map to the north/south/east/west 
+  ;   a map also contains a memory region for all the room's tables 
   ; room:
   ;   a room is a collection of tiles, falgs and actor tables
 
diff --git a/src/mem.s b/src/mem.s
index e536848..47ef253 100644
--- a/src/mem.s
+++ b/src/mem.s
@@ -15,6 +15,8 @@ mem_init:
   ld a, GM_GAME
   ld [game_mode], a
 
+  call mbc1_ram_enable 
+
   ret
 
 ; copies memory from one location to another 
@@ -64,3 +66,19 @@ shadow_oam_to_oam:
   jr nz, @wait REL
   ret 
 shadow_oam_to_oam_end:
+
+; MBC1 functions 
+
+  ; ram enable mbc1
+  ; TODO: it is reccomended to disable ram when not 
+  ; using it!
+mbc1_ram_enable:
+  ld a, 0xA
+  ld [MBC1_SRAM_ENABLE], a
+  ret
+
+
+mbc1_ram_disable:
+  xor a, a
+  ld [MBC1_SRAM_ENABLE], a
+  ret
diff --git a/src/wram.s b/src/wram.s
index 58d47d7..aaae8e7 100644
--- a/src/wram.s
+++ b/src/wram.s
@@ -70,16 +70,12 @@ player: .adv player_size
   ; pause all other update execution until then
 damage_anim: .adv 1
 
+; map region 
+
 #define MAP_W 10
 #define MAP_H 10
 #define MAP_TOTAL_ROOMS MAP_W * MAP_H
 
-; struct map
-.se 0
-; list of room pointers 
-.de map_room_ptrs, 2 * MAP_TOTAL_ROOMS 
-.de map_size, 0
-
   ; rooms are 9x9 meta tiles 
 #define ROOM_W 10
 #define ROOM_H 8
@@ -98,6 +94,7 @@ damage_anim: .adv 1
 
   ; current room struct 
   ; same layout as room struct itself 
+  ; always should point at the current map's memory region 
 curr_room_struct: 
   ; pointer to current room struct 
 curr_room: .adv 2