Apple-2-SW/dos33fsprogs
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keen: cycle counting closer

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This commit is contained in:
Vince Weaver 2024-05-09 21:28:31 -04:00
parent 4e0fdf6968
commit e8298357b4
1 changed files with 65 additions and 28 deletions
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93
games/keen/story.s
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@ -67,11 +67,12 @@ load_background:
;===========================
; main loop
;===========================
; 14 + 16 * (16 + 40*(16) + 19 + 7) + 17 + 17*40
; 14 + 16 * ( 682 ) + 697
; 14 + 10912 + 697
; 11623 / 65 = 179 lines
; 14 + 16 * (16 + 40*(16) + 19 + 7) + 17 + 17*40 -1
; 14 + 16 * ( 682 ) + 696
; 14 + 10912 + 696
; 11622 / 65 = ~179 lines
test1:
draw_loop:
ldx #0 ; line counter ; 2
@ -130,7 +131,7 @@ in_next_page:
; 7
inc INH ; 5
lda #0 ; 2
nop
nop ; 2
; 16
in_done:
@ -151,7 +152,7 @@ in_done:
;==================
; draw message
;==================
; -1
ldx #17 ; 2
lda gr_offsets_low,X ; 4+
sta OUTL ; 3
@ -175,14 +176,11 @@ message_text_loop:
; -1
; 11623
;===================================
; can we do this constant time?
;===================================
; no keys pressed = 41
; invalid key pressed = 41
; up pressed =
; down pressed =
; 11622
;==============================================
; let's do the keyboard stuff in constant time
;==============================================
check_keypress:
lda KEYPRESS ; 4
@ -242,38 +240,75 @@ done_key_69:
nop
done_key_76:
; 11623+76 = 11699
test2:
; 11622+76 = 11698
;==========================
; measured: 2DB2 = 11698
;==========================
; want to delay total of 144+70 lines, 214
; 214*65 = 13910
; -11699
; -11698
; =========
; 2211
; 2212
; want to delay 2211 - 4 = 2207 - 20 = 2187/9 = 243
; 243/256= 0 r 243
; want to delay 2212 - 4 = 2208 - 20 = 2188
; need multiple of 9
inc $0 ; nop5
inc $0 ; nop5
; 2178/9=242
; 242/256= 0 r 242
;
lda #0 ; 2
ldy #243 ; 2
ldy #242 ; 2
jsr delay_loop
; want to delay 6*8*65 = 3120+4550 = 7670
; want to delay 7670 - 15 - 12 = 7643 - 20 = 7623/9 = 847
; 905/256=3 r 79
test3:
;================================
; should be: 2212
; measured: $8A4 = 2212
;================================
inc $00 ; nop5
inc $00 ; nop5
at_set_gr:
;=======================================
; want to delay 6*8*65 = 3120
; want to delay 3120 - 15 - 7 = 3098 - 20 = 3078/9 = 342
; 342/256=1 r 86
inc $0 ; nop5
nop ; nop2
bit SET_GR ; 4
lda #3 ; 2
ldy #79 ; 2
lda #1 ; 2
ldy #86 ; 2
jsr delay_loop
bit SET_TEXT ; 4
;done_key:
;=======================
; measured $c2f = 3117
; expected = 3120-3 = 3117
test4:
jmp draw_loop ; 3
@ -297,6 +332,8 @@ do_up_up:
bne up_ok_ok ; bra ; 3
; 48
.align $100
up_ok:
; 39
inc $0 ; nop5