[A83] Re: tst + tstio instructions
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[A83] Re: tst + tstio instructions
Perhaps the best opcode that people don't use much is SBC A,A. It is very
very useful. It sets A=$FF if carry is set (and leaves carry set), and set
A=$00 if no carry.
The most obvious use is sign extension:
;sign extend A into HL
ld l,a
add a,a
sbc a,a
ld h,a
There are many other uses where you might normally use a jr.
-----Original Message-----
From: assembly-83-bounce@lists.ticalc.org
[mailto:assembly-83-bounce@lists.ticalc.org]On Behalf Of Hyperbyte
Sent: Monday, July 02, 2001 8:07 AM
To: assembly-83@lists.ticalc.org
Subject: [A83] Re: tst + tstio instructions
You probably mean that if it contains a 2 at the end, it's junk to us...
Includes OUT0, OTIM* OTDM*, (SLP), [
but
IND, INDR, INI and INIR don;t have that (yeah, I found more insturctions :-)
What do they do?
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