maria-developers team mailing list archive

[Paul McCullagh <paul.mccullagh@xxxxxxxxxxxxx>]

Thanks Kristian!

On Dec 12, 2011, at 1:08 PM, Kristian Nielsen wrote:

> Hi Paul,
> 
> It seems a patch is needed for PBXT to build on 32-bit x86 in some cases:
> 
> Elena Stepanova <elenst@xxxxxxxxxxxxxxxx> writes:
> 
>> lock_xt.h: Assembler messages:
>> lock_xt.h:70: Error: bad register name `%sil'
> 
>> After some re-installation and long digging, I found the ancient bug
>> report http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10153 which gets
>> re-filed regularly, the last time was a few months ago. They say it's
>> a code problem, and suggest replacing the '=r' constraint with '=q'. I
>> did so in all 4 lines that gcc complained about, and finally got it
>> work.
> 
> It seems correct to me that the "q" constraint must be used rather than "r"
> for the 8-bit case. Below patch should do it (we will apply this in MariaDB).
> 
> - Kristian.
> 
> === modified file 'storage/pbxt/src/lock_xt.h'
> --- storage/pbxt/src/lock_xt.h	2010-05-06 12:57:15 +0000
> +++ storage/pbxt/src/lock_xt.h	2011-12-12 11:34:54 +0000
> @@ -67,9 +67,9 @@ inline void xt_atomic_inc1(volatile xtWo
> #elif defined(XT_ATOMIC_GNUC_X86)
> 	xtWord1 val;
> 
> -	asm volatile ("movb %1,%0" : "=r" (val) : "m" (*mptr) : "memory");
> +	asm volatile ("movb %1,%0" : "=q" (val) : "m" (*mptr) : "memory");
> 	val++;
> -	asm volatile ("xchgb %1,%0" : "=r" (val) : "m" (*mptr), "0" (val) : "memory");
> +	asm volatile ("xchgb %1,%0" : "=q" (val) : "m" (*mptr), "0" (val) : "memory");
> #elif defined(XT_ATOMIC_SOLARIS_LIB)
> 	atomic_inc_8(mptr);
> #else
> @@ -91,9 +91,9 @@ inline xtWord1 xt_atomic_dec1(volatile x
> #elif defined(XT_ATOMIC_GNUC_X86)
> 	xtWord1 val2;
> 
> -	asm volatile ("movb %1, %0" : "=r" (val) : "m" (*mptr) : "memory");
> +	asm volatile ("movb %1, %0" : "=q" (val) : "m" (*mptr) : "memory");
> 	val--;
> -	asm volatile ("xchgb %1,%0" : "=r" (val2) : "m" (*mptr), "0" (val) : "memory");
> +	asm volatile ("xchgb %1,%0" : "=q" (val2) : "m" (*mptr), "0" (val) : "memory");
> 	/* Should work, but compiler makes a mistake?
> 	 * asm volatile ("xchgb %1, %0" : : "r" (val), "m" (*mptr) : "memory");
> 	 */
> 



--
Paul McCullagh
PrimeBase Technologies
www.primebase.org
www.blobstreaming.org
pbxt.blogspot.com