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.DB $01, $02, $04, $08, $10, $20, $40, $80
.PADTO 0x0040
VBlank:
JP $mem_vblank_jump_instruction
.PADTO 0x0048
STAT:
JP $mem_stat_jump_instruction
.PADTO 0x0100
Start:
JP =Initialize_RAM
.PADTO 0x0104
Header:
.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
.Title:
.DB $50, $79, $6f, $6e, $20, $41, $64, $76
.PADTO 0x13f
.Manufacturer_code:
.PADTO 0x143
.CGB_Flag: .DB $69
.Licensee_code_new: .DB $00, $00
.SGB_Flag: .DB $00
.MBC: .DB $01
.ROM_size: .DB $00 ; Will be set after assembly by build scripts
.RAM_size: .DB $00 ; The .sav cartridge kind of ram
.Destination_code: .DB $01 ; Overseas
.Licensee_code_old: .DB $00
.Version_number: .DB $42
.Header_checksum: .DB $00 ; Will be set after assembly by build scripts
.Global_checksum: .DB $00, $00 ; Will be set after assembly by build scripts
Initialize_RAM:
LD SP, $fffe
; LCDC
XOR A
LD $reg_lcd_controller, A
; Disable Interrupts
LD A, $00
LD $reg_interrupt_enable, A
Empty_WRAM:
LD HL, $C000
.loop:
XOR A
LD (HL+), A
LD A, $D0
CP H
JR NZ, =.loop
CALL =VBlank_Wait
Empty_VRAM: ; (Clear screen)
LD HL, $VRAM_start ; 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 A, $palette_normal
LD $reg_bg_palette, A
LD $mem_prepared_color_palette, A
; OBJ0 Palette
LD A, $obj_palette_normal
LD $reg_obj0_palette, A
; OBJ1 Palette (frozen, shadow)
LD A, $obj_palette_frozen
LD $reg_obj1_palette, A
; Interrupt jmp instruction
LD A, $c3 ; Unconditional imm16 jump
LD ($mem_vblank_jump_instruction), A
LD ($mem_stat_jump_instruction), A
Initialize_Window_GUI:
LD A, $48
LD $reg_window_y, A
LD A, $6f
LD $reg_window_x, A
LD HL, $9d80
.top_bar_loop:
LD A, $10
LD (HL+), A
LD A, L
CP $94
LD $reg_lcd_status, A
JR NZ, =.top_bar_loop
LD HL, $9c80
LD BC, $00a0
LD DE, =Dialogue_Box_Tilemap_data
CALL =memcpy
LD HL, $9c00
LD BC, $0080
LD DE, =Cost_Window_Tilemap_data
CALL =memcpy
Copy_OAM_DMA_Transfer_Routine_To_HRAM:
LD HL, $OAM_DMA_Transfer_routine
LD DE, =OAM_DMA_Transfer_routine_src
LD BC, $000a
CALL =memcpy
JP =Entrypoint
OAM_DMA_Transfer_routine_src:
LD A, high($mem_oam_buffer)
LD ($46), A
LD A, $28 ; delay for a total of 4×40 = 160 M-cycles
.wait:
DEC A ; 1 M-cycle
JR NZ, =.wait ; 3 M-cycles
RET
.end:
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