From: Tom Lord <lord@emf.net>
To: dewar@gnat.com
Cc: gcc@gcc.gnu.org, ja_walker@earthlink.net
Subject: Re: Sythetic registers: modrm/gas question.
Date: Mon, 06 Jan 2003 19:47:00 -0000 [thread overview]
Message-ID: <200301051248.EAA23500@emf.net> (raw)
In-Reply-To: <20030105114202.8AB15F2D6B@nile.gnat.com> (dewar@gnat.com)
> How do I tell gas to assemble an operand as a one-byte offset
> instead of a four-byte offset?
>
> e.g.
>
> MOV eax,[ebp + 4]
>
> Does it "just know?"
Yes, of course it "just knows", that's why your guess that gcc
is generating poor code seems ill-informed. It is inconceivable
that *any* compiler would use four byte offsets to access the
local stack frame.
_That's_ rude.
The question since it could almost certainly have been answered with a
five-minute experiment (what, you don't have the necessary platform
around?)
The caustic reply (beginning at "that's why...") because it is
illogical and prejudicial: the synthregs proposal is argued for
at a much higher level than would require that close an examination
of GCC's generated code -- and by-eye examination of that code
doesn't at all easily help us decide if/when synthregs is a win.
Or are you good at simulating complex caches in your head based
on disassembly listings and demand that we all are as well?
-t
next prev parent reply other threads:[~2003-01-06 19:42 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-01-05 12:28 Robert Dewar
2003-01-06 5:04 ` Andy Walker
2003-01-06 19:47 ` Tom Lord [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-01-07 3:13 Robert Dewar
2003-01-05 18:13 Robert Dewar
2003-01-05 20:15 ` Michael S. Zick
2003-01-05 14:24 Robert Dewar
2003-01-05 16:56 ` Michael S. Zick
2003-01-05 17:37 ` Michael S. Zick
2003-01-05 22:33 ` Tom Lord
2003-01-05 13:25 Robert Dewar
2003-01-06 5:36 ` Andy Walker
2003-01-06 19:42 ` Tom Lord
2003-01-05 6:08 Andy Walker
2003-01-06 23:54 ` Mike Stump
2003-01-07 6:15 ` Andy Walker
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