Bug of gas (binutils-2.9.1.0.23): Wrong code for SETHI on SPARC
Ian Lance Taylor
ian@airs.com
Fri Apr 2 16:42:00 GMT 1999
From: hjl@lucon.org (H.J. Lu)
Date: Fri, 2 Apr 1999 16:10:48 -0800 (PST)
> gas out of binutils-2.9.1.0.23 (and older versions) has a severe bug
> for the SPARC platform (sparc-sun-solaris2.6), i.e. it generates
> wrong code for
>
> sethi 0x4000,%i0
>
> (and probably in all other cases where sethi is used without the
> %hi(...)-construct).
>
> The sethi instruction has following suggested assembly syntax
> (see SPARC Architecture Manual):
>
> sethi const22,reg
>
> const22 is a 22-bit constant that is placed by sethi in the most
> significant 22 bits of reg (while it zeroes the 10 least significant
> bits of reg). Therefore we would expect the value 0x100000 in %i0
> after the execution of ``sethi 16384''. Instead of this, gas
> modifies the given constant such that 0x4000 will be found in %i0
> afterwards. This would have been equivalent to
>
> sethi %hi(0x4000),%i0
Here is a new patch. Please discard my last patch to tc-sparc.c.
Let me know what you get.
Thanks.
H.J.
---
Fri Apr 2 16:05:25 1999 H.J. Lu (hjl@gnu.org)
* sparc-opc.c: Change "sethi" from "h,d" to "n,d".
I don't think that can be right. I think it will do the wrong thing
for
sethi foo,%i0
Ian
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