Signetics 2650 & 2636 programming/Tutorial code - objects
Tutorial code - Objects
[edit | edit source]This is the code for the tutorial Objects
 | This code block must be merged with the standard 'Hardware definitions' code before it can be assembled |
reset_vector:
bcta,un reset
interrupt_vector:
retc,un
reset:
lodi,r0 $20 ;initialise program status word, just to be sure!
lpsu ;inhibit interrupts, stack pointer=0
lpsl ;register bank 0, without carry, arithmetic compare
eorz r0
stra,r0 effects ;initialise the 74LS378
bsta,un InitPVI ;initialise video chip
endless:
bctr,un endless
;===================================================================
; subroutine - initialise PVI
InitPVI:
eorz r0 ;r0 = 0
lodi,r3 $CA ;set 1F00-1FC9 to 00 (most of PVI)
loop1: ;sets all colours to black, turns off sound, score 1 field at top.
stra,r0 shape1,r3-
brnr,r3 loop1
lodi,r0 $02
stra,r0 scoreformat
lodi,r0 $aa ;blank the score digits
stra,r0 score12
lodi,r0 $aa
stra,r0 score34
lodi,r0 $78 ;screen black
stra,r0 backgnd
lodi,r0 %00000011
stra,r0 colours12 ; obj 1 white, 2 red
lodi,r0 %00101001
stra,r0 colours34 ; obj 3 green, 4 yellow
lodi,r0 %11100100
stra,r0 objectsize
lodi,r3 $0E
loopISe: ;load object descriptors
loda,r0 one,r3-
stra,r0 shape1,r3
loda,r0 two,r3
stra,r0 shape2,r3
loda,r0 three,r3
stra,r0 shape3,r3
loda,r0 four,r3
stra,r0 shape4,r3
brnr,r3 loopISe
retc,un
one:
db $08
db $18
db $08
db $08
db $08
db $08
db $08
db $08
db $1c
db $1c
db 10 ;hc
db 10 ;hcb
db 20 ;vc
db 20 ;vcb
two:
db $1c
db $3e
db $22
db $02
db $0e
db $18
db $30
db $20
db $3e
db $3e
db 40
db 35
db 60
db 10
three:
db $7c
db $7c
db $04
db $04
db $1c
db $1c
db $04
db $04
db $7c
db $7c
db 60
db 120
db 90
db 250
four:
db $40
db $40
db $40
db $40
db $48
db $7e
db $7e
db $08
db $08
db $08
db 100
db 110
db 0
db 255 ;