From: Richard Henderson <rth@cygnus.com>
To: Weiwen Liu <liu@hepvms.physics.yale.edu>
Cc: rth@cygnus.com, egcs@cygnus.com
Subject: Re: complex support on alpha
Date: Sun, 05 Oct 1997 18:28:00 -0000 [thread overview]
Message-ID: <19971005182519.53305@dot.cygnus.com> (raw)
In-Reply-To: <Pine.OSF.3.96.971005190110.31383A-100000@hepunix1.physics.yale.edu>
On Sun, Oct 05, 1997 at 07:14:09PM -0400, Weiwen Liu wrote:
> On Wed, 1 Oct 1997, Richard Henderson wrote:
>
> > Well, it is enough to compile those examples properly, but it is
> > not completely correct. The problem is that complex numbers should
> > be treated as two distinct arguments on Alpha, which affects padding
> > of the arguments passed on the stack.
[...]
> On an alpha-dec-osf4.0, this patch correctly compiles the following test
> program with F=char, short, int, long, float, double:
No good.
(1) It is still treating complex float as an 8-byte struct not two
_separate_ float arguments. I sent you f2a and f2b so that you
could verify that their arguments wound up in the same place, but
f2b:
lds $f10,16($30)
lds $f11,20($30)
f2a:
lds $f10,16($30)
lds $f11,24($30)
(2) f1, the one with odd numbered arguments, is _completely_ wrong:
f1:
lda $30,-16($30)
.prologue 0
sts $f21,8($30)
lds $f10,12($30)
Did we write to 12($30), which is below the vfp? No. Your program
happened to run because of this bit from main:
sts $f3,-4($30)
which is a big no-no. No writes may be made below $sp. You take a
signal after that instruction and your data will be corrupted.
r~
next prev parent reply other threads:[~1997-10-05 18:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
1997-10-01 21:03 Weiwen Liu
1997-10-01 22:34 ` Richard Henderson
1997-10-02 9:22 ` Weiwen Liu
1997-10-02 10:46 ` Richard Henderson
1997-10-05 16:16 ` Weiwen Liu
1997-10-05 18:28 ` Richard Henderson [this message]
1997-10-02 20:35 ` Jim Wilson
1997-10-04 14:33 ` Kamil Iskra
1997-10-04 18:29 ` Richard Henderson
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