3 files changed, 137 insertions, 22 deletions
diff --git a/src/engine/bank07.asm b/src/engine/bank07.asm
index e2922bb..ed87acc 100644
--- a/src/engine/bank07.asm
+++ b/src/engine/bank07.asm
@@ -50,7 +50,8 @@ Func_1c056: ; 1c056 (7:4056)
 
 INCLUDE "data/warps.asm"
 
-Func_1c33b: ; 1c33b (7:433b)
+; loads data from the map header of wCurMap
+LoadCurMapHeaderData: ; 1c33b (7:433b)
 	push hl
 	push bc
 	push de
@@ -66,7 +67,7 @@ Func_1c33b: ; 1c33b (7:433b)
 	ld a, [hli]
 	ld [wCurTilemap], a
 	ld a, [hli]
-	ld c, a
+	ld c, a ; CGB tilemap variant
 	ld a, [hli]
 	ld [wd28f], a
 	ld a, [hli]
diff --git a/src/engine/bank1c.asm b/src/engine/bank1c.asm
index 15a4647..b94729a 100644
--- a/src/engine/bank1c.asm
+++ b/src/engine/bank1c.asm
@@ -330,5 +330,103 @@ Func_70214: ; 70214 (1c:4214)
 Unknown_7024a: ; 7024a (1c:424a)
 	INCROM $7024a, $7036a
 
-Func_7036a: ; 7036a (1c:436a)
-	INCROM $7036a, $74000
+; decompresses palette data depending on wd132
+; then sends it as SGB packet
+SetSGB2AndSGB3MapPalette: ; 7036a (1c:436a)
+	ld a, [wConsole]
+	cp CONSOLE_SGB
+	ret nz ; return if not SGB
+	ld a, [wd132]
+	or a
+	ret z ; not valid
+
+	push hl
+	push bc
+	push de
+	ld a, [wd132]
+	add a
+	ld c, a
+	ld b, $0
+	ld hl, .pal_data_pointers
+	add hl, bc
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+	call DecompressSGBPalette
+
+	; load palettes to wTempSGBPacket
+	ld hl, wBGMapBuffer
+	ld de, wTempSGBPacket + 1 ; PAL Packet color #0 (PAL23's SGB2)
+	ld bc, 8 ; pal size
+	call CopyDataHLtoDE
+	ld hl, wBGMapBuffer + 34
+	ld de, wTempSGBPacket + 9 ; PAL Packet color #4 (PAL23's SGB3)
+	ld bc, 6
+	call CopyDataHLtoDE
+
+	xor a
+	ld [wTempSGBPacket + 15], a
+	ld hl, wTempSGBPacket
+	ld a, $1
+	ld [hl], a
+	call Func_704c7
+	call SendSGB
+	pop de
+	pop bc
+	pop hl
+	ret
+
+.pal_data_pointers
+	dw $722f ; unused
+	dw $722f ; MAP_SGB_PALETTE_1
+	dw $7253 ; MAP_SGB_PALETTE_2
+	dw $7277 ; MAP_SGB_PALETTE_3
+	dw $729a ; MAP_SGB_PALETTE_4
+	dw $72bd ; MAP_SGB_PALETTE_5
+	dw $72e0 ; MAP_SGB_PALETTE_6
+	dw $7304 ; MAP_SGB_PALETTE_7
+	dw $7328 ; MAP_SGB_PALETTE_8
+	dw $734b ; MAP_SGB_PALETTE_9
+	dw $736f ; MAP_SGB_PALETTE_10
+
+	INCROM $703cb, $70403
+
+DecompressSGBPalette: ; 70403 (1c:4403)
+	push hl
+	push bc
+	push de
+	ld c, [hl]
+	inc hl
+	ld b, [hl]
+	inc hl
+	push bc
+	ld e, l
+	ld d, h
+	ld b, HIGH(wc000)
+	call InitBGMapDecompression
+	pop bc
+	ld de, wBGMapBuffer
+	call DecompressBGMap
+	pop de
+	pop bc
+	pop hl
+	ret
+; 0x7041d
+
+	INCROM $7041d, $704c7
+
+; load some values to wTempSGBPacket
+Func_704c7: ; 704c7 (1c:44c7)
+	push af
+	push hl
+	inc hl
+	ld a, $9c
+	ld [hli], a
+	ld a, $63
+	ld [hl], a
+	pop hl
+	pop af
+	ret
+; 0x704d3
+
+	INCROM $704d3, $74000
diff --git a/src/engine/bank20.asm b/src/engine/bank20.asm
index 5b4de83..639f31a 100644
--- a/src/engine/bank20.asm
+++ b/src/engine/bank20.asm
@@ -1,8 +1,22 @@
 Func_80000: ; 80000 (20:4000)
-	INCROM $80000, $80028
+	call ClearSRAMBGMaps
+	xor a
+	ld [wTextBoxFrameType], a
+	call Func_8003d
+	farcall Func_c37a
+	farcall Func_c9c7
+	call Func_801a1
+	farcall Func_c3ff
+	ld a, [wCurMap]
+	cp $00
+	ret nz
+	farcall Func_10f2e
+	farcall Func_10fbc
+	ret
+; 0x80028
 
 Func_80028: ; 80028 (20:4028)
-	call Func_801f1
+	call ClearSRAMBGMaps
 	ld bc, $0000
 	call Func_80077
 	farcall Func_c9c7
@@ -12,8 +26,8 @@ Func_80028: ; 80028 (20:4028)
 ; 0x8003d
 
 Func_8003d: ; 8003d (20:403d)
-	farcall Func_1c33b
-	farcall Func_7036a
+	farcall LoadCurMapHeaderData
+	farcall SetSGB2AndSGB3MapPalette
 	ld bc, $0
 	call Func_80077
 	ld a, $80
@@ -38,12 +52,12 @@ Func_8003d: ; 8003d (20:403d)
 ; 0x80077
 
 Func_80077: ; 80077 (20:4077)
-	ld a, $1
-	ld [wBGMapCopyMode], a
+	ld a, TRUE
+	ld [wWriteBGMapToSRAM], a
 	jr Func_80082
 
 	xor a
-	ld [wBGMapCopyMode], a
+	ld [wWriteBGMapToSRAM], a
 ;	fallthrough
 
 Func_80082: ; 80082 (20:4082)
@@ -213,13 +227,13 @@ Func_80148: ; 80148 (20:4148)
 	ret
 
 ; copies BG Map data pointed by hl
-; to either VRAM or SRAM, depending on wBGMapCopyMode
+; to either VRAM or SRAM, depending on wWriteBGMapToSRAM
 ; de is the target address in VRAM,
 ; if SRAM is the target address to copy,
 ; copies data to s0BGMap or s1BGMap
 ; for VRAM0 or VRAM1 respectively
 CopyBGDataToVRAMOrSRAM: ; 8016e (20:416e)
-	ld a, [wBGMapCopyMode]
+	ld a, [wWriteBGMapToSRAM]
 	or a
 	jp z, SafeCopyDataHLtoDE
 
@@ -307,16 +321,16 @@ Func_801a1: ; 801a1 (20:41a1)
 	pop hl
 	ret
 
-; Clears the first x800 bytes of S1:a000
-Func_801f1: ; 801f1 (20:41f1)
+; clears s0BGMap and s1BGMap
+ClearSRAMBGMaps: ; 801f1 (20:41f1)
 	push hl
 	push bc
 	ldh a, [hBankSRAM]
 	push af
-	ld a, $1
+	ld a, BANK(s0BGMap) ; SRAM 1
 	call BankswitchSRAM
-	ld hl, $a000
-	ld bc, $0800
+	ld hl, s0BGMap
+	ld bc, $800 ; s0BGMap + s1BGMap
 	xor a
 	call FillMemoryWithA
 	pop af
@@ -1110,8 +1124,8 @@ Func_80b89: ; 80b89 (20:4b89)
 	push bc
 	push af
 	ld c, a
-	ld a, $01
-	ld [wBGMapCopyMode], a
+	ld a, TRUE
+	ld [wWriteBGMapToSRAM], a
 	ld b, $00
 	ld hl, wd323
 	add hl, bc
@@ -1129,9 +1143,9 @@ Func_80b89: ; 80b89 (20:4b89)
 Func_80ba4: ; 80ba4 (20:4ba4)
 	push af
 	xor a
-	ld [wBGMapCopyMode], a
+	ld [wWriteBGMapToSRAM], a
 	pop af
-;	Fallthrough
+;	fallthrough
 
 Func_80baa: ; 80baa (20:4baa)
 	push hl
@@ -1150,11 +1164,13 @@ Func_80baa: ; 80baa (20:4baa)
 	push af
 	ld a, [wd23a + 1]
 	push af
+
 	ld b, $0
 	ld hl, wd323
 	add hl, bc
 	ld a, $1
 	ld [hl], a
+
 	ld a, c
 	add a
 	ld c, a