Re: [stella] "Illegal" opcodes

Subject: Re: [stella] "Illegal" opcodes
From: "Thomas Jentzsch" <tjentzsch@xxxxxx>
Date: Tue, 20 Jun 2000 10:02:12 +0200
I've compared undoc.asm (DASM: John Saeger) with 
another source
(Sally: http://alt.xmission.com/~trevin/atari/6502_insn_set.html).
This is the result (use a fixed font to read the table):

DASM	Sally
-----------------------------------
anc		=
ane		axe		different mnemonics only
arr		=
asr		=
dcp		=
isb		=
las		=
lax		=
lxa		xea		different mnemonics only
nop		=
rla		=
rra		=
sax		=
sbx		asx		different mnemonics only		
sha		ax7		M' = A & X & (ADDR_HI+1)           | M' = A & X & 07 
shs		xs7		S' = A & X; M' =  S' & (ADDR_HI+1) | S' = A & X; M' = S' & 07
shx		sx7		M' = X & (ADDR_HI+1)               | M' = X & 07
shy		sy7		M' = Y & (ADDR_HI+1)               | M' = Y & 07
slo		=
sre		=

I haven't found many differences, mostly different 
mnemonics. But sha, shs, shx and shy are explained a
bit more complicated in undoc.asm. There are also 
other sources in the internet, with more different 
informations. Look at
http://wwwstud.ira.uka.de/~s_tomczy/opcodes.html

So someone must check these opcodes.

Thomas
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