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Mail Archives: djgpp/1995/05/28/13:19:13

Date: Sun, 28 May 1995 16:32:01 +0000 (GMT)
From: "Paal-Kr. Engstad" <pke AT engstad DOT ingok DOT hitos DOT no>
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Setting up segment descriptors.

In a 3D application's texture map routine, the essentials are to copy=20
bitmap data to a screen buffer. However, the i386 processor has few=20
registers, and since the calculations requires some use and tricks of=20
registers it would be nice if I could set up for instance %es to contain=20
the bitmap, and %fs (or %gs) to point to the screen buffer. This would=20
essentially free up some registers, and probably save some instructions.

So, is this possible? Are there any FAQ's on this matter?

Also, I hate the ix86's idiv instruction (64 bit/32 bit). If there will=20
be an overflow (result > 32 bit number), there will be an exception. Are=20
there anyone out there with a fast 64bit/32bit stub?

Lastly, does anyone know why this construct:
=09movb (%edx, %di), %al
is not allowed in gas? (Note: %di, not %edi.)

PKE.
 _   _   _____
| | | | |_   _|      Siv.ing P=E5l-Kristian Engstad=20
| |_| | _ | |  _ _   Email : pke AT engstad DOT IngOk DOT HiTos DOT No
|  _  || || | / //   M$-Dog: engstad AT IngOk DOT HiTos DOT No       =20
| | | || || || O |   WWW   : http://linux.ingok.hitos.no/~rogon
|_| |_||_||_|//_/    Tlf.  : +47 77 66 03 34
Troms=F8 College / Section of Economics and Engineering / N-9005 TROMS=D8

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