mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-11-16 23:20:43 +00:00
133 lines
2.6 KiB
ArmAsm
133 lines
2.6 KiB
ArmAsm
; Tiny Xdraw
|
|
|
|
; repeatedly draws an image from an Apple II shape table
|
|
|
|
; can arbitrarily point to any memory location as a source of these
|
|
; some look amazing but depend on random machine state
|
|
; to be deterministic you should probably stick to
|
|
; $E7-$F0 (the program itself)
|
|
; $D000-$FFFF (the ROMs)
|
|
; shapetables are a bit complicated to explain here, but they are a
|
|
; series of bytes ending with a $00
|
|
; (note if you point to a zero, it will be interpreted as an
|
|
; action not an end)
|
|
; each byte specifies up to 3 actions, DRAW + UP DOWN LEFT RIGHT or
|
|
; NODRAW + UP DOWN LEFT RIGHT
|
|
; It is vector scaling with SCALE we hardcode to $20 and rotation
|
|
; which gets set to 0 after the first iteration, (which is
|
|
; why the first shape has arbitrary rotation and gets left)
|
|
|
|
; we are xdrawing so it will XOR with the current pixels on the screen
|
|
|
|
; NUP=0 UP=4 zz yyy xxx , does xxx yyy zz
|
|
; NRT=1 RT=5
|
|
; NDN=2 DN=6
|
|
; NLT=3 LT=7
|
|
|
|
; zero page locations
|
|
HGR_SHAPE = $1A
|
|
HGR_SHAPE2 = $1B
|
|
HGR_BITS = $1C
|
|
GBASL = $26
|
|
GBASH = $27
|
|
A5H = $45
|
|
XREG = $46
|
|
YREG = $47
|
|
; C0-CF should be clear
|
|
; D0-DF?? D0-D5 = HGR scratch?
|
|
HGR_DX = $D0 ; HGLIN
|
|
HGR_DX2 = $D1 ; HGLIN
|
|
HGR_DY = $D2 ; HGLIN
|
|
HGR_QUADRANT = $D3
|
|
HGR_E = $D4
|
|
HGR_E2 = $D5
|
|
HGR_X = $E0
|
|
HGR_X2 = $E1
|
|
HGR_Y = $E2
|
|
HGR_COLOR = $E4
|
|
HGR_HORIZ = $E5
|
|
HGR_SCALE = $E7
|
|
HGR_SHAPE_TABLE = $E8
|
|
HGR_SHAPE_TABLE2= $E9
|
|
HGR_COLLISIONS = $EA
|
|
HGR_ROTATION = $F9
|
|
FRAME = $FC
|
|
XPOS = $FD
|
|
YPOS = $FF
|
|
|
|
KEYPRESS = $C000
|
|
KEYRESET = $C010
|
|
|
|
; ROM calls
|
|
HGR2 = $F3D8
|
|
HGR = $F3E2
|
|
HPOSN = $F411
|
|
XDRAW0 = $F65D
|
|
XDRAW1 = $F661
|
|
RESTORE = $FF3F
|
|
|
|
.zeropage
|
|
.globalzp rot_smc
|
|
|
|
tiny_xdraw:
|
|
|
|
jsr HGR2 ; Hi-res, full screen ; 3
|
|
; Y=0, A=0 after this call
|
|
|
|
; we load at $E7 which is HGR_SCALE, so HGR_SCALE gets
|
|
; the value of the above JSR instruction ($20)
|
|
|
|
|
|
; A and Y are 0 here.
|
|
; X is left behind by the boot process?
|
|
|
|
txa
|
|
jsr HPOSN ; set screen position to X= (y,x) Y=(a)
|
|
; saves X,Y,A to zero page
|
|
; after Y= orig X/7
|
|
; A and X are ??
|
|
tiny_loop:
|
|
|
|
; values for shape table
|
|
; Y X
|
|
; 00 E7 = neat
|
|
; 00 EB = OK
|
|
; 00 EF = good
|
|
; F0 01 = cool, let's go with it
|
|
|
|
smc2:
|
|
; ldy #$d0 ; point to top byte of shape address
|
|
ldy #$d3 ; point to top byte of shape address
|
|
|
|
smc1:
|
|
ldx #$00 ; point to bottom byte of shape address
|
|
|
|
|
|
; ROT in A
|
|
|
|
; this will be 0 2nd time through loop, arbitrary otherwise
|
|
lda #0 ; ROT=0
|
|
jsr XDRAW0 ; XDRAW 1 AT X,Y
|
|
; Both A and X are 0 at exit
|
|
; Z flag set on exit
|
|
; Y varies
|
|
|
|
|
|
lda KEYPRESS
|
|
bpl tiny_loop
|
|
|
|
; key pressed
|
|
bit KEYRESET
|
|
|
|
jsr HGR2
|
|
|
|
inc smc1+1
|
|
bne tiny_loop
|
|
inc smc2+1
|
|
|
|
jmp tiny_loop ; bra
|
|
|
|
|
|
|
|
|