Subject: Re: [stella] 6502 basics: signed LSR From: "Andrew Davie" <atari2600@xxxxxxxxxxxxx> Date: Mon, 16 Feb 2004 08:15:58 +1100 |
Less bytes (just!), more cycles... lda var asl a ror var "Efficient" can mean different things, so the above may be useful, too :) Cheers A ----- Original Message ----- From: "Thomas Jentzsch" <tjentzsch@xxxxxx> To: <stella@xxxxxxxxxxx> Sent: Monday, February 16, 2004 6:10 AM Subject: Re: [stella] 6502 basics: signed LSR > KirkIsrael wrote: > > > Is there a better way of dividing a signed 1-byte integer > > by 2 than this? (which says, if var is positive, just do LSR, > > otherwise LSR and OR w/ -128 i.e. #%10000000 ) > > Yup: > > lda var > cmp #$80 > ror > sta var > > Have fun! > Thomas > _______________________________________________________ > Thomas Jentzsch | *** Every bit is sacred ! *** > tjentzsch at web dot de | > > -------------------------------------------------------------------------- -------------------- > Archives (includes files) at http://www.biglist.com/lists/stella/archives/ > Unsub & more at http://www.biglist.com/lists/stella/ > > > ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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