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RE: Silly question about ARM thumb
- From: "Henry Zhu" <zhu_henry at immenstar dot com>
- To: 'Øyvind Harboe' <oyvind dot harboe at zylin dot com>,<ecos-discuss at sources dot redhat dot com>
- Date: Tue, 22 Feb 2005 09:12:51 -0800
- Subject: RE: [ECOS] Silly question about ARM thumb
Hi,
Here is a paper on the performance comparison of arm and thumb code.
http://www.cs.arizona.edu/people/arvind/papers/lctes02.pdf
Mixed code is said to show the best performance.
I am using eCos with -mthumb and -mthumb-interwork, and with -O2 on my ARM7
and ARM9 targets. The code size is reduced considerably. Speed performance
is also great. Only small part of assembly code of eCos is in Arm mode. All
others including app are in Thumb mode.
Henry
-----Original Message-----
From: ecos-discuss-owner@ecos.sourceware.org
[mailto:ecos-discuss-owner@ecos.sourceware.org] On Behalf Of Øyvind Harboe
Sent: Tuesday, February 22, 2005 5:26 AM
To: ecos-discuss@sources.redhat.com
Subject: [ECOS] Silly question about ARM thumb
If the code is smaller and faster, why aren't all ARM programs compiled
w/ARM thumb?
Tell me about the downside, I can live with the upside :-)
I'm pretty happy with code-size on the Atmel EB40a, so I'm a bit
averse to changing things.
This posting quotes 20% code size decrease and 50% speed increase.
http://sourceware.org/ml/ecos-discuss/2002-11/msg00036.html
--
Øyvind Harboe
http://www.zylin.com
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