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8bitworkshop/presets/vcs/vcslib/demo_kernels.ca65
2023-10-30 23:16:36 -05:00

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.include "vcs-ca65.inc"
.setcpu "6502x"
.macpack longbranch
.global _kernel_2pp_4pfa
.global _kernel_2pfasync
.importzp _k_height
.importzp _k_ypos
.importzp _k_bitmap
.importzp _k_colormap
.importzp _k_playfield
.importzp tmp1
.import _k_asyncpf
.import _reset_gfx
_k_pftmp = tmp1 ; no one's using this just now, right?
.include "kernel.inc"
.code
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Display Kernel
; - two double-line players w/ colormap
; - two missiles, variable height
; - versatile playfield, 4 lines per change (no cross page)
; Modifies: _k_ypos, _k_playfield
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
.proc _kernel_2pp_4pfa
tay
ldx #0
@loop:
; first two lines, fetch PF0 and PF1
DO_PCOLOR 0
DO_PCOLOR 1
DO_DRAW 0,1
DO_DRAW 1,0
DO_MISSILE 2
DO_MISSILE_NOP 3
DO_VERSATILE_PF_1
dey
; second two lines, fetch PF2 and write PF registers
DO_PCOLOR 0
DO_PCOLOR 1
DO_DRAW 0,1
DO_DRAW 1,0
DO_MISSILE_NOP 2
DO_MISSILE 3
DO_VERSATILE_PF_2
dey
jne @loop
jmp _reset_gfx
.endproc
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Display Kernel
; - async playfield, 6 lines per change
; - playfield data should be page-aligned
; Modifies: _k_playfield
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
.proc _kernel_2pfasync
tay
loop2:
dey
ldx #5
loop:
DO_PFWRITE_2
DO_WSYNC
lda _k_asyncpf,y
sta _k_pftmp,x
DO_PFWRITE
stx COLUPF ; fun vfx rainbow
dex
bmi loop2
dey
jne loop
jmp _reset_gfx
.endproc