svn commit: r256042 - in projects/random_number_generator: share/examples/kld/random_adaptor sys/conf sys/dev/glxsb sys/dev/hifn sys/dev/random sys/dev/rndtest sys/dev/safe sys/dev/syscons sys/dev/...

[Mark R V Murray]

On 4 Oct 2013, at 08:23, Konstantin Belousov <kostikbel at gmail.com> wrote:

> On Fri, Oct 04, 2013 at 08:09:48AM +0100, Mark R V Murray wrote:
>> 
>> On 4 Oct 2013, at 08:05, Konstantin Belousov <kostikbel at gmail.com> wrote:
>> 
>>> On Fri, Oct 04, 2013 at 06:55:06AM +0000, Mark Murray wrote:
>>>> #ifdef __amd64__
>>>> -	    ".byte\t0x48,0x0f,0xc7,0xf0\n\t" /* rdrand %rax */
>>>> +	    "rdrand\t%%rax\n\t"
>>>> 	    "jnc\t1f\n\t"
>>>> 	    "movq\t%%rax,%1\n\t"
>>>> 	    "movl\t$8,%%eax\n"
>>>> #else /* i386 */
>>>> -	    ".byte\t0x0f,0xc7,0xf0\n\t" /* rdrand %eax */
>>>> +	    "rdrand\t%%eax\n\t"
>>>> 	    "jnc\t1f\n\t"
>>>> 	    "movl\t%%eax,%1\n\t"
>>>> 	    "movl\t$4,%%eax\n"
>>> This should break the build with the in-tree binutils, i.e. when gcc
>>> is used.  The same for the chunks of the VIA asm.
>> 
>> This is likely a case of me getting it wrong, but I thought we were headed away from worrying about that? Or is that only in 11-current? If so I'll revert that bit.
>> 
> 
> I assure you about the infinite stream of complains if the build with the
> base gcc is broken on x86.  It is not catched by tinderboxes, but people
> are fast to report.

*Sigh* OK :-). I'll revert for 10 but not 11-Current. OK? :-P

> Also, if changing the .byte to mnemonic, it makes sense to loose the
> constraints and allow the compiler to generate direct store from rdrand
> to the target address.  I.e., do something like this (not tested):
> 	rdrand	%1
> 	jnc	1f
> 	movl	$8,%%eax
> 1:

Thanks!

M
-- 
Mark R V Murray

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