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From: s887212@minyos.xx.rmit.oz.au (Stephen Riehm [Romulis])
Newsgroups: comp.sys.cbm
Subject: Re: random numbers in ML
Message-ID: <6467@minyos.xx.rmit.oz.au>
Date: 5 Dec 90 01:35:50 GMT
References: <6389@minyos.xx.rmit.oz.au> <1990Dec3.072647.28822@evax.arl.utexas.edu>
Distribution: comp
Organization: RMIT Computer Centre, Melbourne Australia.
Lines: 36

cs4344af@evax.arl.utexas.edu (Fuzzy Fox) writes:

>In article <6389@minyos.xx.rmit.oz.au> s887212@minyos.xx.rmit.oz.au (Stephen Riehm [Romulis]) writes:
>>According to some books I have it IS POSSIBLE to use the
>>oscillator for the third voice...

>Here's some untested code written from the above:

>INIT:	LDA	#$FF    ; set frequency to $FFFF
>	STA	$D40E
>	STA	$D40F
>	LDA	#$80    ; select noise waveform
>	STA	$D412
>	LDA	#$8F	; Volume = 15, but no voice 3 output
>	STA	$D418
>	RTS

>RAND:	LDA	$D41B
>	RTS		; Random number returned in A.

After testing this I found that it works fine.. however there are some
things to note:
] If you want two numbers simultaneously you will need to put a small delay
before getting the second number.
ie: ldx $d41b ; ldy $d41b   often results in X. == Y.
solution: ldx $d41b
    wait  cpx $d41b
	  beq $wait
	  ldy $d41b
	  rts

ldx $d41b ; ldy #$00; loop dey; bne $loop; ldy $d41b ; rts
also works nicely...


thanx to those who responded!