Author: Carey
Date: 14:46:44 09/27/05
Go up one level in this thread
On September 27, 2005 at 16:04:55, Gerd Isenberg wrote: >>The SEX instruction was always amusing to tell about.... But it was, >>unfortunately, a very boring instrunction. > >Why is SEX boring ;-? [grin] Back then, a lot of people didn't know about cpus etc., and it was kind of fun to tell them that your computer really knew about SEX... But then you had to admit it was just an abreviation... Bummer. >Doesn't it combine a lda and arithmetic shift right 8 instruction? >I guess because of the fixed register a,b association. > >Btw. is the BIT-instruction similar to x86 bt- or to test-instruction? >6809 has tst-instruction as well, but no idea wehther it performs a temporary >and. Been a while since I did the 6809, but if I remember right... BIT actually tested the bits in reg A or B. Do an "AND" and throw away the result, keeping just the flags. TST also existed but just did a fake 'load' to set the zero or negative bits. The 6809 had a lot of useful features, two index registers, two stacks, movable direct page, etc., but most of the features just weren't needed for chess programming.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.