Subject: Re: [stella] 6502 basics: signed LSR From: Russ Perry Jr <slapdash@xxxxxxx> Date: Sun, 15 Feb 2004 14:35:55 -0600 |
At 3:25 PM -0500 2/15/04, Eric Ball wrote: >> Thomas Jentzsch wrote: >> > Yup: >> > lda var >> > cmp #$80 >> > ror >> > sta var >> Ha ha... I was feeling silly enough after reading Eric's code, >> but this seals it. Back to lurking for ME I think. :-) > Trust Thomas to come up with the most efficient & elegant way to do > something with the 6502. At least I was thinking the right way -- I wanted to not have two LSRs in the code and was trying to find a way to preserve the sign info. Sadly, I ended up with more shifting in the end since I wasn't aware of the CMP opcode. I've really gotta get familiar with the instruction set one of these days... -- //*================================================================++ || Russ Perry Jr 2175 S Tonne Dr #114 Arlington Hts IL 60005 || || 847-952-9729 slapdash@xxxxxxx [NEW!] VIDEOGAME COLLECTOR! || ++================================================================*// ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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