// This code makes every door load the right section of the background when using BG_Data type 000E
// Made by P.JBoy, 10/05/2009, for Super Metroid (JU)[!]


arch snes.cpu ; lorom ; noheader


//---------------------Hijacks----------------------


org $82E5D9		//\
jsr $F777		//} When coming out a door
nop #15			///

org $82E9E7		//\
jsr $F777		//} When loading from the ship
nop #15			///


//----------------------Code------------------------


org $82F777
sep #$20

lda.b #$80              //\
sta.b $00               //} Stores the low byte of the bg source address

ldx.w $078D             //\
lda.l $830007,x         //|
cmp.b #$01              //|
bne BETA                //|
                        //|
ALPHA:                  //|
ldx.w #$4C00            //|
bra GAMMA               //} Gets the right section of VRAM to write to
                        //|
BETA:                   //|
cmp.b #$03              //|
beq ALPHA               //|
                        //|
ldx.w #$4800            ///

GAMMA:
rep #$20                //\
asl #3                  //} Gets the right section of BG to load
adc.w #$8AB1            ///

sta.b $01               // Stores bank and high bytes of the bg source

stx.b $03               // Stores bg dest.

lda.w #$0800            //\
sta.b $05               //} Stores bg size

ldy.w #$0000            // Makes the game load from 7E0000 for BG_Data

sty.b $07               // Ends BG_Data loop

rts