Date: Sun, 9 Oct 94 15:47:54 EDT
From: peprbv AT cfa0 DOT harvard DOT edu (Bob Babcock)
To: buers AT DG1 DOT CHEMIE DOT UNI-KONSTANZ DOT DE
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: bug in movedata (or in gas), with fix
Reply-To: babcock AT cfa DOT harvard DOT edu

Replying to a message from 2 weeks ago:

> In the file dosmem.s in libsrc/c/dos gas produces for the jcxz zero
> instructions code for a jump with 16 bit displacements. This will mask
> the high word of EIP, so (when cx is zero) it will jump from say
> 0x00012345 to 0x00002347 instead of the correct 0x00012347.  In the
> gas manual, there is mentioned, that using jcxz may be risky, but I
> really don't understand what they mean. The code should get assembled
> correctly (with 8-bit displacement, "short" jump).  The following
> patch seems to fix the problem (using jz instead of jcxz).

I just looked at some of my code with the debugger.  The two jcxz
instructions in dosmem.s seem to be assembled with 8-bit displacements in the
standard distribution, not 16-bit.  Did you rebuild the library, and if so,
did you use a different version of gas than DJ uses?