Tip: Check this thread to find extremely useful diagrams and data.
Not logged in.
00a2af rep #$20 ;>16-bit A 00a2b1 stz $1888 ;>Default Y displacement to 0 00a2b4 lda $1887 ;\If quake timer 0, skip displacement 00a2b7 beq $a2d3 ;/ 00a2b9 dec $1887 ;>Decrement timer 00a2bc and #$0003 ;>MOD by 4 00a2bf asl a ;\Index to 16-bit table 00a2c0 tay ;/ 00a2c1 lda $a1ce,y ;>Displacement (at bank $00) 00a2c4 bit $0bf4 ;\Check if displacement would require tiles to be loaded at the top and bottom of screen 00a2c7 bvc $a2cb ;/to prevent glitched tiles from appearing. 00a2c9 dec ;\Move layer down 2 pixels as a failsafe to prevent garbled tiles 00a2ca dec ;/ 00a2cb sta $1888 ;>Store Y displacement 00a2ce clc ;\Move layer 1 Y position 00a2cf adc $1c ;| 00a2d1 sta $1c ;/ 00a2d3 sep #$20 ;>8-bit A
The purpose of this site is not to distribute copyrighted material, but to honor one of our favourite games.