[PATCH] 6fire: Convert byte_rev_table uses to bitrev8

Joe Perches joe at perches.com
Tue Oct 28 14:22:49 PDT 2014


Use the inline function instead of directly indexing the array.

This allows some architectures with hardware instructions
for bit reversals to eliminate the array.

Signed-off-by: Joe Perches <joe at perches.com>
---
On Sun, 2014-10-26 at 23:46 -0700, Joe Perches wrote:
> On Mon, 2014-10-27 at 14:37 +0800, Wang, Yalin wrote:
> > this change add CONFIG_HAVE_ARCH_BITREVERSE config option,
> > so that we can use arm/arm64 rbit instruction to do bitrev operation
> > by hardware.
[]
> > diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
> > index 7ffe03f..ef5b2bb 100644
> > --- a/include/linux/bitrev.h
> > +++ b/include/linux/bitrev.h
> > @@ -3,6 +3,14 @@
> >  
> >  #include <linux/types.h>
> >  
> > +#ifdef CONFIG_HAVE_ARCH_BITREVERSE
> > +#include <asm/bitrev.h>
> > +
> > +#define bitrev32 __arch_bitrev32
> > +#define bitrev16 __arch_bitrev16
> > +#define bitrev8 __arch_bitrev8
> > +
> > +#else
> >  extern u8 const byte_rev_table[256];

 sound/usb/6fire/firmware.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/6fire/firmware.c b/sound/usb/6fire/firmware.c
index 3b02e54..62c25e7 100644
--- a/sound/usb/6fire/firmware.c
+++ b/sound/usb/6fire/firmware.c
@@ -316,7 +316,7 @@ static int usb6fire_fw_fpga_upload(
 
 	while (c != end) {
 		for (i = 0; c != end && i < FPGA_BUFSIZE; i++, c++)
-			buffer[i] = byte_rev_table[(u8) *c];
+			buffer[i] = bitrev8((u8)*c);
 
 		ret = usb6fire_fw_fpga_write(device, buffer, i);
 		if (ret < 0) {





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