dos33fsprogs/demos/outline2023/midline.s
2023-05-18 17:04:33 -04:00

310 lines
5.6 KiB
ArmAsm

; a 256-byte midline demo for Outline 2023
; by Vince `deater` Weaver / dSr
; requires an Apple IIe
.include "zp.inc"
.include "hardware.inc"
; 198 bytes -- proof of concept
; 76 bytes -- optimize Apple II Forever printing code
; 183 bytes -- stable window
; 248 bytes -- sine code added
; 274 bytes -- after much frustration, things sorta working
; 261 bytes -- use zp for sine generation
; 257 bytes -- inline sine generation
; 259 bytes -- fix sine generation initialization, shave some message print
; 247 bytes -- start replacing sather delays with something more compact
; 229 bytes -- finish replacing sather delays
; 228 bytes -- optimize and center the middle area
; 226 bytes -- init some of zero page to zero
; 244 bytes -- switch to hires too
; 247 bytes -- clear HGR
; 264 bytes -- add HGR
; 263 bytes -- better nop
; 263 bytes -- don't init zero page anymore
; 259 bytes -- combine delay_49 routines
; 258 bytes -- init discrete
; GOAL = 256 (Outline 2023 says header doesn't count, is usually 4 on Apple II)
sine = $c00 ; location of sine table
midline:
;================================
; Clear screen and setup graphics
;================================
ldx #0
stx DELTA
stx DELTAH
; setup graphics
sta SETMOUSETEXT ; enable mouse text for Apple char
;==============================
; set up sine table
; X must be 0 when calling
.include "sinetable.s" ; Y is FF after this
; A = 1, X = $40
;====================================================
; setup text page1 screen of "Apple II Forever" text
;====================================================
; X is $40 which is probably OK
; ldx #0
restart:
tay ; reset Y to 0 (or 1 first time through)
inx
beq print_done
print_loop:
lda a2_string,Y
beq restart
jsr COUT ; output char in A to stdout
iny
bne print_loop
print_done:
;===================
; do graphics
jsr HGR ; A and Y=0 now
sta FULLGR
jsr HPLOT0 ; set screen position to X= (y,x) Y=(a)
; saves X,Y,A to zero page
; after Y= orig X/7
; A and X are ??
tiny_loop:
lda #$F6 ; ROT=$F6
tay
tax
dex
jsr XDRAW0 ; XDRAW 1 AT X,Y
; Both A and X are 0 at exit
; Z flag set on exit
; Y varies
dec $0a ; is $4c due to basic
bne tiny_loop ;
;==================================
; get exact vblank region
;==================================
; code by Sather
; "Understanding the Apple IIe"
poll1:
lda VBLANK ; Find end of VBL
bmi poll1 ; Fall through at VBL
poll2:
lda VBLANK
bpl poll2 ; Fall through at VBL' ; 2
lda $00 ;nop3 ; Now slew back in 17029 cycle loops ; 3
lp17029:
; delay 17020
lda #7 ; 2
ldy #96 ; 2
jsr size_delay ; 17012
nop ; 2
nop ; 2
lda VBLANK ; Back to VBL yet? ; 4
nop ; ; 2
bmi lp17029 ; no, slew back ; 2/3
;==============================
; do the cycle counting
;==============================
cycle_start:
;==============================
; top
; 2
top_smc:
ldx #66 ; 2
bne top7 ; bra ; 3/2
top_loop:
pha ; 3
pla ; 4
top7:
; 7
; lda #0 ; 2
; ldy #3 ; 2
; 11
; want to delay 49
jsr delay_49
; jsr size_delay ; 47
; 58
nop ; 2
; 60
dex ; 2
bne top_loop ; 3/2
;===================================
; middle
; -1
ldx #56 ; 2
bne middle_4 ; bra ; 3
middle_loop:
nop ; 2
nop ; 2
middle_4:
; 4
inc $0 ; nop5 ; 5
; 9
jsr delay_16_setgr ; 16
; 25
jsr delay_16_settext ; 16
; 41
jsr delay_16_setgr ; 16
; 57
lda $0 ; nop3 ; 3
; 60
dex ; 2
bne middle_loop ; 3/2
; -1
bottom_smc:
ldx #118 ; 2
bne bottom_4 ; bra ; 3
bottom_loop:
nop ; 2
nop ; 2
; 4
bottom_4:
; 4
; lda #0 ; 2
; ldy #3 ; 2
; 8
; want to delay 50
jsr delay_49
; jsr size_delay ; 47
; 55
lda $0 ; nop3 ; 3
; 58
inx ; 2
cpx #192 ; 2
bcc bottom_loop ; 3/2
; -1
;======================================
; wait 4550 for VBLANK
;======================================
; -1 from before
vblank_start:
; move window
; -1
clc ; 2
lda FRAME ; 3
adc #1 ; 2
sta FRAME ; 3
tay ; save for later ; 2
; 11
lda #0 ; 2
rol ; get carry bit in A ; 2
eor screen_smc+1 ; 4
sta screen_smc+1 ; 4
; 23
screen_smc:
bit LORES ; LORES=C056 HIRES=C057 ; 4
; 27
; FRAME should be in Y
lda sine,Y ; 4 (aligned)
; 31
clc ; 2
adc #2 ; 2
sta top_smc+1 ; 4
adc #56 ; 2
sta bottom_smc+1 ; 4
; 45
; finish delay
; 45
lda #1 ; 2
ldy #241 ; 2
; 49
jsr size_delay ; 4493
; 4542
pha ; 3
pla ; 4
; 4549
jmp cycle_start ; 3
; 4552
; want 4552 here
delay_16_settext:
bit SET_TEXT
rts
delay_16_setgr:
bit SET_GR
rts
delay_49:
lda #0 ; 2
ldy #3 ; 2
;=====================================
; short delay by Bruce Clark
; any delay between 8 to 589832 with res of 9
;=====================================
; 9*(256*A+Y)+8 + 12 for jsr/rts
; A and Y both $FF at the end
size_delay:
delay_loop:
cpy #1
dey
sbc #0
bcs delay_loop
delay_12:
rts
a2_string:
; 012345678901234567 8 9
; .byte "Apple II Forever!! ",'@'+$80," ",0
.byte 'A'+$80,'p'+$80,'p'+$80,'l'+$80,'e'+$80,' '+$80
.byte 'I'+$80,'I'+$80,' '+$80,'F'+$80,'o'+$80,'r'+$80
.byte 'e'+$80,'v'+$80,'e'+$80,'r'+$80,'!'+$80,'!'+$80
.byte ' '+$80,'@'+$00,' '+$80,0