Initial commit

8 files changed, 212 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..567609b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+build/
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..34b242a
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,11 @@
+all: run
+
+build/%.rom: %.gbasm
+	mkdir -p build
+	gbasm $< $@
+
+run: build/main.rom
+	gb $<
+
+clean:
+	rm -rf build
diff --git a/RAM_Var_map b/RAM_Var_map
new file mode 100644
index 0000000..ed1049b
--- /dev/null
+++ b/RAM_Var_map
@@ -0,0 +1,3 @@
+FF80 = Bunny Y position (in px)
+FF81 = Bunny X position (in px)
+FF82 = Current Direction (Up = 1, Right = 2, Down = 3, Left = 4)
diff --git a/bunny.gbasm b/bunny.gbasm
new file mode 100644
index 0000000..b2e6ca3
--- /dev/null
+++ b/bunny.gbasm
@@ -0,0 +1,66 @@
+Initialize_Bunny:
+	LD A, $20
+	LD ($80), A
+	LD A, $20
+	LD ($81), A
+	RET
+
+Move_Bunny:
+	LD A, ($82)
+	CP $00
+	JR Z, =Display_Bunny
+
+	Move_Bunny.check_direction:
+		DEC A
+		LD B, $01
+		BIT 0, A
+		JR NZ, =Move_Bunny.check_direction_end
+		LD B, $FF
+
+	Move_Bunny.check_direction_end:
+
+	BIT 1, A
+	JR NZ, =Move_Bunny.vertical_move
+
+	Move_Bunny.horizontal_move:
+		LD A, ($81)
+		ADD B
+		LD ($81), A
+		JP =Move_Bunny.end
+
+	Move_Bunny.vertical_move:
+		LD A, ($80)
+		ADD B
+		LD ($80), A
+
+	Move_Bunny.end:
+	RET
+
+Display_Bunny: ; X position in B, Y position in C
+	LD A, ($81)
+	LD B, A
+	LD A, ($80)
+	LD C, A
+
+	; First OBJ (left)
+	LD HL, $FE00
+	LD A, C
+	LD (HL+), A
+	LD A, B
+	LD (HL+), A
+	LD A, $01
+	LD (HL+), A
+	INC HL
+	
+	; Second OBJ
+	LD A, B
+	ADD $08
+	LD B, A
+
+	LD A, C
+	LD (HL+), A
+	LD A, B
+	LD (HL+), A
+	LD A, $03
+	LD (HL+), A
+	RET
diff --git a/buttons.gbasm b/buttons.gbasm
new file mode 100644
index 0000000..b2015de
--- /dev/null
+++ b/buttons.gbasm
@@ -0,0 +1,37 @@
+Pad_Button_Check:
+	PUSH AF
+	PUSH BC
+
+	LD A, $20
+	LD ($00), A
+	LD A, ($00)
+	LD C, A
+	LD A, $00
+	
+	Pad_Button_Check.Right:
+		BIT 0, C
+		JR NZ =Pad_Button_Check.Left
+		LD A, $02
+
+	Pad_Button_Check.Left:
+		BIT 1, C
+		JR NZ =Pad_Button_Check.Up
+		LD A, $01
+
+	Pad_Button_Check.Up:
+		BIT 2, C
+		JR NZ =Pad_Button_Check.Down
+		LD A, $03
+
+	Pad_Button_Check.Down:
+		BIT 3, C
+		JR NZ =Pad_Button_Check.End
+		LD A, $04
+
+	Pad_Button_Check.End:
+
+	LD ($82), A
+
+	POP BC
+	POP AF
+	RET
diff --git a/init.gbasm b/init.gbasm
new file mode 100644
index 0000000..1245ce7
--- /dev/null
+++ b/init.gbasm
@@ -0,0 +1,52 @@
+.PADTO 0x0040
+VBlank:
+	CALL =VBLANK_Entrypoint
+	RETI
+
+.PADTO 0x0100
+Start:
+	JP =Empty_VRAM
+
+.PADTO 0x0104
+Nintendo_Logo: ; The Nintendo logo must be stored in bytes 0x104-133
+	.DB $CE,$ED,$66,$66,$CC,$0D,$00,$0B,$03,$73,$00,$83,$00,$0C,$00,$0D 
+	.DB $00,$08,$11,$1F,$88,$89,$00,$0E,$DC,$CC,$6E,$E6,$DD,$DD,$D9,$99 
+	.DB $BB,$BB,$67,$63,$6E,$0E,$EC,$CC,$DD,$DC,$99,$9F,$BB,$B9,$33,$3E 
+	
+.PADTO 0x0134
+Checksum: ; The bytes 0x134-0x14d need to add up to 0xe7 (= 0xff - 0x19)
+	.DB $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
+	.DB $00,$00,$00,$00,$00,$00,$00,$00,$00,$e7
+
+Empty_VRAM: ; (Clear screen)
+	LD hl, $8000 ; We set the HL register to the start of VRAM
+
+Empty_VRAM.loop:
+		XOR A
+		LD (HL+), a 						; We set the memory pointed to by HL to 0 and increase HL
+		LD a, $a0
+		CP h        						; Until h has reached $a0 ($a0000 is the end of VRAM)
+		JR NZ, =Empty_VRAM.loop
+
+	; BG Palette
+	LD DE, $ff47
+	LD A, $e4
+	LD (DE), A
+	
+	; OBJ0 Palette
+	LD DE, $ff48
+	LD A, $e4
+	LD (DE), A
+	
+	; LCDC
+	LD DE, $ff40
+	LD A, (DE)
+	OR $06
+	LD (DE), A
+
+	; Interrupts
+	LD DE, $ffff
+	LD A, $01
+	LD (DE), A
+
+	JP =Entrypoint
diff --git a/main.gbasm b/main.gbasm
new file mode 100644
index 0000000..6b701c8
--- /dev/null
+++ b/main.gbasm
@@ -0,0 +1,20 @@
+.INCLUDE "init.gbasm"
+
+Entrypoint:
+	CALL =Load_Tile
+	CALL =Initialize_Bunny
+	
+	EI
+	Wait_for_VRAM.loop:
+	HALT
+	JP =Wait_for_VRAM.loop
+
+VBLANK_Entrypoint:
+	CALL =Pad_Button_Check
+	CALL =Move_Bunny
+	CALL =Display_Bunny
+	RET
+
+.INCLUDE "tiles.gbasm"
+.INCLUDE "bunny.gbasm"
+.INCLUDE "buttons.gbasm"
diff --git a/tiles.gbasm b/tiles.gbasm
new file mode 100644
index 0000000..f69a87d
--- /dev/null
+++ b/tiles.gbasm
@@ -0,0 +1,22 @@
+
+Tile_Image_Data:
+	.DB $00, $00, $44, $44, $aa, $ee, $aa, $ee, $fe, $b2, $fc, $b4, $fc, $94, $75, $4d
+	.DB $7f, $42, $2f, $30, $1f, $10, $39, $26, $37, $2f, $48, $78, $50, $70, $60, $60
+	.DB $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $c0, $c0
+	.DB $34, $f4, $ce, $3a, $fe, $0a, $fc, $04, $bc, $c4, $5c, $64, $88, $f8, $f0, $f0
+
+Load_Tile:
+	LD HL, $8010
+	LD DE, =Tile_Image_Data
+	LD B, $40
+	Load_Tile.loop0:
+		LD A, (DE)
+		LD (HL+), A
+		INC DE
+		DEC B
+		XOR A
+		CP B
+		JR NZ =Load_Tile.loop0
+	RET
+
+