Subject: Using ARM's half-word data-handling instructions.

From: Dan Jakubiec <[email-masked]>
Date: Mon, 13 Sep 1999 17:24:09 -0700

Is there an easy way to tell if my ARM Linux kernel is compiled using the
ARM v4 half-word data handling instructions?  I've tried to build the Linux
kernel with two different gcc (2.95.1) compilers: one built using the
'--with-cpu=strongarm110' option, and one without this option.  In both
cases, my Linux kernel was approximately the same size.

My understanding (from reading Chris Rutter's notes) was that by default,
the GCC compiler builds an ARM v3 toolchain.  So I thought that by building
an ARM v4 toolchain, I might decrease my image size (by taking advantage of
the half-word instructions).  Have I missed something here?

--
Dan Jakubiec
Systech Corporation
[email-masked]

unsubscribe: body of `unsubscribe linux-arm' to [email-masked]

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From: Philip Blundell <[email-masked]>
Date: Tue, 14 Sep 1999 10:27:08 +0100

In message <[email-masked]>, Dan Jakub
iec writes:
>ARM v4 half-word data handling instructions?

If you mean you just want to see how a particular binary was built, the 
easiest way is "objdump --disassemble foo | grep ldrh" or some such.

>the half-word instructions).  Have I missed something here?

That's correct.  But you won't save much that way -- halfword operations don't 
dominate the kernel by any means, and you only save a couple of words per 
instance.  What were the relative sizes of the two vmlinux files?

p.