[A89] moveq #0,dx

To: <assembly-89@lists.ticalc.org>
Subject: [A89] moveq #0,dx
From: "Scott Noveck" <noveck@pluto.njcc.com>
Date: Sun, 8 Apr 2001 20:55:33 -0400
References: <20010408221207.9C83818003@mx-1.sollentuna.net>
Reply-To: assembly-89@lists.ticalc.org


I recall that a while ago we had a little discussion where we learned that
"moveq #0,dx" is not a valid 68k opcode.  Since you should use clr instead
of moveq to store zero in a register, moveq actually has the range 1 through
8, not zero through seven; if the 68k chip sees the opcode that _would_ be
"moveq #0,dx" it actually stores 8 in that register, not zero.

However, TIGCC had that little bug where it would actually accept and
compile "moveq #0,dx" mistakenly storing 8 in dx, while it would not allow
"moveq #8,dx" which it should.  Was this bug ever fixed?

    -Scott

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