diff mbox

net: wan: sbni: remove assembly crc32 code

Message ID 20131022183625.GA4382@breakpoint.cc
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Sebastian Andrzej Siewior Oct. 22, 2013, 6:36 p.m. UTC 
There is also a C function doing the same thing. Unless the asm code is
110% faster we could stick to the C function.

Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
---

On Tue, Oct 22, 2013 at 01:59:28PM -0400, David Miller wrote:
> 
> Is it really impossible to use the generic crc32 support instead of this
> unsightly custom inline assembler?

Since you asked for this here step 1.

 drivers/net/wan/sbni.c | 89 --------------------------------------------------
 1 file changed, 89 deletions(-)

Comments

David Miller Oct. 22, 2013, 6:38 p.m. UTC | #1 
From: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Date: Tue, 22 Oct 2013 20:36:25 +0200

> 
> There is also a C function doing the same thing. Unless the asm code is
> 110% faster we could stick to the C function.
> 
> Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
> ---
> 
> On Tue, Oct 22, 2013 at 01:59:28PM -0400, David Miller wrote:
>> 
>> Is it really impossible to use the generic crc32 support instead of this
>> unsightly custom inline assembler?
> 
> Since you asked for this here step 1.

If it's that simple, this is definitely what we should do.

On the off chance, is there anyone actually able to test this
change? :-)))
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Andi Kleen Oct. 23, 2013, 2:11 a.m. UTC | #2 
On Tue, Oct 22, 2013 at 08:36:25PM +0200, Sebastian Andrzej Siewior wrote:
> 
> There is also a C function doing the same thing. Unless the asm code is
> 110% faster we could stick to the C function.

I have no idea if it is or not. But doing it this way would be
acceptable for me.

Thanks for the patch.

-Andi
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David Miller Oct. 25, 2013, 11:27 p.m. UTC | #3 
From: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Date: Tue, 22 Oct 2013 20:36:25 +0200

> There is also a C function doing the same thing. Unless the asm code is
> 110% faster we could stick to the C function.
> 
> Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>

Applied.
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diff mbox

Patch

diff --git a/drivers/net/wan/sbni.c b/drivers/net/wan/sbni.c
index 5bbcb5e..388ddf6 100644
--- a/drivers/net/wan/sbni.c
+++ b/drivers/net/wan/sbni.c
@@ -148,10 +148,6 @@  static int  enslave( struct net_device *, struct net_device * );
 static int  emancipate( struct net_device * );
 #endif
 
-#ifdef __i386__
-#define ASM_CRC 1
-#endif
-
 static const char  version[] =
 	"Granch SBNI12 driver ver 5.0.1  Jun 22 2001  Denis I.Timofeev.\n";
 
@@ -1551,88 +1547,6 @@  __setup( "sbni=", sbni_setup );
 
 /* -------------------------------------------------------------------------- */
 
-#ifdef ASM_CRC
-
-static u32
-calc_crc32( u32  crc,  u8  *p,  u32  len )
-{
-	register u32  _crc;
-	_crc = crc;
-	
-	__asm__ __volatile__ (
-		"xorl	%%ebx, %%ebx\n"
-		"movl	%2, %%esi\n" 
-		"movl	%3, %%ecx\n" 
-		"movl	$crc32tab, %%edi\n"
-		"shrl	$2, %%ecx\n"
-		"jz	1f\n"
-
-		".align 4\n"
-	"0:\n"
-		"movb	%%al, %%bl\n"
-		"movl	(%%esi), %%edx\n"
-		"shrl	$8, %%eax\n"
-		"xorb	%%dl, %%bl\n"
-		"shrl	$8, %%edx\n"
-		"xorl	(%%edi,%%ebx,4), %%eax\n"
-
-		"movb	%%al, %%bl\n"
-		"shrl	$8, %%eax\n"
-		"xorb	%%dl, %%bl\n"
-		"shrl	$8, %%edx\n"
-		"xorl	(%%edi,%%ebx,4), %%eax\n"
-
-		"movb	%%al, %%bl\n"
-		"shrl	$8, %%eax\n"
-		"xorb	%%dl, %%bl\n"
-		"movb	%%dh, %%dl\n" 
-		"xorl	(%%edi,%%ebx,4), %%eax\n"
-
-		"movb	%%al, %%bl\n"
-		"shrl	$8, %%eax\n"
-		"xorb	%%dl, %%bl\n"
-		"addl	$4, %%esi\n"
-		"xorl	(%%edi,%%ebx,4), %%eax\n"
-
-		"decl	%%ecx\n"
-		"jnz	0b\n"
-
-	"1:\n"
-		"movl	%3, %%ecx\n"
-		"andl	$3, %%ecx\n"
-		"jz	2f\n"
-
-		"movb	%%al, %%bl\n"
-		"shrl	$8, %%eax\n"
-		"xorb	(%%esi), %%bl\n"
-		"xorl	(%%edi,%%ebx,4), %%eax\n"
-
-		"decl	%%ecx\n"
-		"jz	2f\n"
-
-		"movb	%%al, %%bl\n"
-		"shrl	$8, %%eax\n"
-		"xorb	1(%%esi), %%bl\n"
-		"xorl	(%%edi,%%ebx,4), %%eax\n"
-
-		"decl	%%ecx\n"
-		"jz	2f\n"
-
-		"movb	%%al, %%bl\n"
-		"shrl	$8, %%eax\n"
-		"xorb	2(%%esi), %%bl\n"
-		"xorl	(%%edi,%%ebx,4), %%eax\n"
-	"2:\n"
-		: "=a" (_crc)
-		: "0" (_crc), "g" (p), "g" (len)
-		: "bx", "cx", "dx", "si", "di"
-	);
-
-	return  _crc;
-}
-
-#else	/* ASM_CRC */
-
 static u32
 calc_crc32( u32  crc,  u8  *p,  u32  len )
 {
@@ -1642,9 +1556,6 @@  calc_crc32( u32  crc,  u8  *p,  u32  len )
 	return  crc;
 }
 
-#endif	/* ASM_CRC */
-
-
 static u32  crc32tab[] __attribute__ ((aligned(8))) = {
 	0xD202EF8D,  0xA505DF1B,  0x3C0C8EA1,  0x4B0BBE37,
 	0xD56F2B94,  0xA2681B02,  0x3B614AB8,  0x4C667A2E,