69 lines
1.8 KiB
NASM
69 lines
1.8 KiB
NASM
printline subroutine
|
|
tsx
|
|
inx
|
|
lda STACK,x
|
|
sta ZPA0
|
|
lda STACK+1,x
|
|
sta ZPA1
|
|
.loop
|
|
inc ZPA0
|
|
bne .cont
|
|
inc ZPA1
|
|
.cont
|
|
ldy #0
|
|
lda (ZPA0),y
|
|
beq .cleanup
|
|
ora #%10000000
|
|
jsr COUT
|
|
bne .loop
|
|
.cleanup
|
|
lda ZPA0
|
|
sta STACK,x
|
|
.end
|
|
lda ZPA1
|
|
sta STACK+1,x
|
|
rts
|
|
|
|
rand subroutine
|
|
jsr rand64k ;Factors of 65535: 3 5 17 257
|
|
jsr rand32k ;Factors of 32767: 7 31 151 are independent and can be combined
|
|
lda sr1+1 ;can be left out
|
|
eor sr2+1 ;if you dont use
|
|
tay ;y as suggested
|
|
lda sr1 ;mix up lowbytes of SR1
|
|
eor sr2 ;and SR2 to combine both
|
|
rts
|
|
|
|
;periode with 65535
|
|
;10+12+13+15
|
|
rand64k subroutine
|
|
lda sr1+1
|
|
asl
|
|
asl
|
|
eor sr1+1
|
|
asl
|
|
eor sr1+1
|
|
asl
|
|
asl
|
|
eor sr1+1
|
|
asl
|
|
rol sr1 ;shift this left, "random" bit comes from low
|
|
rol sr1+1
|
|
rts
|
|
|
|
;periode with 32767
|
|
;13+14
|
|
rand32k subroutine
|
|
lda sr2+1
|
|
asl
|
|
eor sr2+1
|
|
asl
|
|
asl
|
|
ror sr2 ;shift this right, random bit comes from high - nicer when eor with sr1
|
|
rol sr2+1
|
|
rts
|
|
|
|
;feel free to set seeds as wished, if put in zeropage some speed-boost is
|
|
;the result. For example sr1=$5c sr2=5e would fit
|
|
sr1 dc.w $a55a
|
|
sr2 dc.w $7653 |