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falling_apple: inline the delay

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This commit is contained in:
Vince Weaver 2018-10-21 14:40:42 -04:00
parent 298dfe0c52
commit 6b651b5fad
1 changed files with 24 additions and 26 deletions
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50
megademo/falling_apple.s
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@ -109,8 +109,6 @@ faloopB:dex ; 2
; Total of 17030 cycles to get back to where was
; We want to alternate between page1 and page2 every 65 cycles
; vblank = 4550 cycles to do scrolling
; 2 + 48*( (4+2+25*(2+3)) + (4+2+23*(2+3)+4+5)) + 9)
; 48*[(6+125)-1] + [(6+115+10)-1]
@ -142,12 +140,31 @@ page1_loop: ; delay 115+(7 loop)+4 (bit)+4(extra)
;======================================================
; We have 4550 cycles in the vblank, use them wisely
;======================================================
; do_nothing should be 4550+1 -2-9 -7= 4533
;======================================================
; We have 4550 cycles in the vblank, use them wisely
;======================================================
; 4550 cycles
; +1-2 from above
; -10 keypress
;================
; 4539
jsr fa_do_nothing ; 6
; Try X=24 Y=36 cycles=4537 R2
nop ; 2
ldy #36 ; 2
faloop1:ldx #24 ; 2
faloop2:dex ; 2
bne faloop2 ; 2nt/3
dey ; 2
bne faloop1 ; 2nt/3
;=====================
; check for keypress
; 10 cycles
lda KEYPRESS ; 4
bpl fa_no_keypress ; 3
@ -161,25 +178,6 @@ fa_done:
rts ; 6
;=================================
; do nothing
;=================================
; and take 4533-6 = 4527 cycles to do it
fa_do_nothing:
; Try X=4 Y=174 cycles=4525 R2
nop ; 2
ldy #174 ; 2
faloop1:ldx #4 ; 2
faloop2:dex ; 2
bne faloop2 ; 2nt/3
dey ; 2
bne faloop1 ; 2nt/3
rts ; 6
;.include "../asm_routines/gr_unrle.s"