[U-Boot] [PATCH] arm: make arch memset/memcpy to work with Thumb2 builds

[Bill Pringlemeir]

>>> ---
>>> arch/arm/lib/memset.S | 40 ++++++++++++++++++++--------------------
>>> 1 file changed, 20 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S
>>> index 0cdf895..4fe38f6 100644
>>> --- a/arch/arm/lib/memset.S
>>> +++ b/arch/arm/lib/memset.S
>>>>> -18,8 +18,8 @@
>>> 1:	subs	r2, r2, #4		@ 1 do we have enough
>>> 	blt	5f			@ 1 bytes to align with?
>>> 	cmp	r3, #2			@ 1
>>> -	strltb	r1, [r0], #1		@ 1
>>> -	strleb	r1, [r0], #1		@ 1
>>> +	strblt	r1, [r0], #1		@ 1
>>> +	strble	r1, [r0], #1		@ 1

>> To test this, can we just use 'objdump'.  The hex codes should be
>> identical; there is only one encoding.  It should produce the same
>> binaries.  No need to run test-suites, etc.

On 20 Nov 2014, jeroen at myspectrum.nl wrote:

> yes, I should be trivial to test (and find the trivial problem, with
> the patch I attached). I am wondering though if all version of
> gas accept the suffix notation... any idea?

One part of the answer is here,

 https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=history;f=gas/config/tc-arm.c;hb=HEAD

The 'strCCb' version is definitely more popular in older ARM books.
Certainly there could be bugs and/or patched versions that make a
difference.  Probably it would be helpful to know what versions are
supported.

Back in 1999 it seems that the code at least tries to take conditions
anywhere,

 https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blob;f=gas/config/tc-arm.c;hb=858f4ff6ff40a73f2a569fc8886157568f08c6db#l6099

I think it is most likely to result in a parse error if it wasn't
supported.  Any version since Thumb2/Unified (2003-2005?) was introduced
should be accepting this syntax with less issues.  Ie, it seems like a
better way forward.

Historical versions are here,

http://ftp.mirrorservice.org/sites/sourceware.org/pub/binutils/old-releases/

Who knows if some vendor patched things to mess something up?  Probably
grabbing an older 'gas' version and verifying it was the same binary
before/after the patch would probably be fair confirmation?  I don't
think you can 100% guarantee this doesn't break with some archaic
vendors gas.

Fwiw,
Bill Pringlemeir.