On Mon, Oct 27, 2008 at 05:02:41PM -0700, David Daney wrote:
> Enable the basic bitops like __ffs and so forth that would normally be
> on if we were MIPS32 or MIPS64, but aren't since Cavium sets neither.
>
> Signed-off-by: Tomaso Paoletti <tpaoletti@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: David Daney<ddaney@xxxxxxxxxxxxxxxxxx>
Counter proposal. Instead of making the #ifdefery worse get rid of it
entirely and give the optimizer a little hand with __builtin_constant_p
to get things right for every platform.
(This patch has gone through it-looks-good-so-it-must-be-good QA ...)
Ralf
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
arch/mips/include/asm/bitops.h | 108 +++++++++++++++++++++++------------
arch/mips/include/asm/cpu-features.h | 2
2 files changed, 75 insertions(+), 35 deletions(-)
Index: linux-mips/arch/mips/include/asm/bitops.h
===================================================================
--- linux-mips.orig/arch/mips/include/asm/bitops.h
+++ linux-mips/arch/mips/include/asm/bitops.h
@@ -558,39 +558,67 @@ static inline void __clear_bit_unlock(un
__clear_bit(nr, addr);
}
-#if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
-
/*
* Return the bit position (0..63) of the most significant 1 bit in a word
* Returns -1 if no 1 bit exists
*/
static inline unsigned long __fls(unsigned long x)
{
- int lz;
+ int num;
- if (sizeof(x) == 4) {
+ if (BITS_PER_LONG == 32 &&
+ __builtin_constant_p(cpu_has_mips_r) && cpu_has_mips_r) {
__asm__(
" .set push \n"
" .set mips32 \n"
" clz %0, %1 \n"
" .set pop \n"
- : "=r" (lz)
+ : "=r" (num)
: "r" (x));
- return 31 - lz;
+ return 31 - num;
}
- BUG_ON(sizeof(x) != 8);
+ if (BITS_PER_LONG == 64 &&
+ __builtin_constant_p(cpu_has_mips64) && cpu_has_mips64) {
+ __asm__(
+ " .set push \n"
+ " .set mips64 \n"
+ " dclz %0, %1 \n"
+ " .set pop \n"
+ : "=r" (num)
+ : "r" (x));
+
+ return 63 - num;
+ }
- __asm__(
- " .set push \n"
- " .set mips64 \n"
- " dclz %0, %1 \n"
- " .set pop \n"
- : "=r" (lz)
- : "r" (x));
+ num = BITS_PER_LONG - 1;
- return 63 - lz;
+#if BITS_PER_LONG == 64
+ if (!(word & (~0ul << 32))) {
+ num -= 32;
+ word <<= 32;
+ }
+#endif
+ if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
+ num -= 16;
+ word <<= 16;
+ }
+ if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
+ num -= 8;
+ word <<= 8;
+ }
+ if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
+ num -= 4;
+ word <<= 4;
+ }
+ if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
+ num -= 2;
+ word <<= 2;
+ }
+ if (!(word & (~0ul << (BITS_PER_LONG-1))))
+ num -= 1;
+ return num;
}
/*
@@ -614,21 +642,41 @@ static inline unsigned long __ffs(unsign
*/
static inline int fls(int word)
{
- __asm__("clz %0, %1" : "=r" (word) : "r" (word));
+ int r;
- return 32 - word;
-}
+ if (__builtin_constant_p(cpu_has_mips_r) && cpu_has_mips_r) {
+ __asm__("clz %0, %1" : "=r" (word) : "r" (word));
-#if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPS64)
-static inline int fls64(__u64 word)
-{
- __asm__("dclz %0, %1" : "=r" (word) : "r" (word));
+ return 32 - word;
+ }
- return 64 - word;
+ r = 32;
+ if (!x)
+ return 0;
+ if (!(x & 0xffff0000u)) {
+ x <<= 16;
+ r -= 16;
+ }
+ if (!(x & 0xff000000u)) {
+ x <<= 8;
+ r -= 8;
+ }
+ if (!(x & 0xf0000000u)) {
+ x <<= 4;
+ r -= 4;
+ }
+ if (!(x & 0xc0000000u)) {
+ x <<= 2;
+ r -= 2;
+ }
+ if (!(x & 0x80000000u)) {
+ x <<= 1;
+ r -= 1;
+ }
+ return r;
}
-#else
+
#include <asm-generic/bitops/fls64.h>
-#endif
/*
* ffs - find first bit set.
@@ -646,16 +694,6 @@ static inline int ffs(int word)
return fls(word & -word);
}
-#else
-
-#include <asm-generic/bitops/__ffs.h>
-#include <asm-generic/bitops/__fls.h>
-#include <asm-generic/bitops/ffs.h>
-#include <asm-generic/bitops/fls.h>
-#include <asm-generic/bitops/fls64.h>
-
-#endif /*defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64) */
-
#include <asm-generic/bitops/ffz.h>
#include <asm-generic/bitops/find.h>
Index: linux-mips/arch/mips/include/asm/cpu-features.h
===================================================================
--- linux-mips.orig/arch/mips/include/asm/cpu-features.h
+++ linux-mips/arch/mips/include/asm/cpu-features.h
@@ -141,6 +141,8 @@
#define cpu_has_mips64 (cpu_has_mips64r1 | cpu_has_mips64r2)
#define cpu_has_mips_r1 (cpu_has_mips32r1 | cpu_has_mips64r1)
#define cpu_has_mips_r2 (cpu_has_mips32r2 | cpu_has_mips64r2)
+#define cpu_has_mips_r (cpu_has_mips32r1 | cpu_has_mips32r2 | \
+ cpu_has_mips64r1 | cpu_has_mips64r2)
#ifndef cpu_has_dsp
#define cpu_has_dsp (cpu_data[0].ases & MIPS_ASE_DSP)
