diff options
Diffstat (limited to 'arch/cris/include/arch-v10/arch/bitops.h')
-rw-r--r-- | arch/cris/include/arch-v10/arch/bitops.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/arch/cris/include/arch-v10/arch/bitops.h b/arch/cris/include/arch-v10/arch/bitops.h new file mode 100644 index 00000000000..be85f6de25d --- /dev/null +++ b/arch/cris/include/arch-v10/arch/bitops.h @@ -0,0 +1,73 @@ +/* asm/arch/bitops.h for Linux/CRISv10 */ + +#ifndef _CRIS_ARCH_BITOPS_H +#define _CRIS_ARCH_BITOPS_H + +/* + * Helper functions for the core of the ff[sz] functions, wrapping the + * syntactically awkward asms. The asms compute the number of leading + * zeroes of a bits-in-byte and byte-in-word and word-in-dword-swapped + * number. They differ in that the first function also inverts all bits + * in the input. + */ +static inline unsigned long cris_swapnwbrlz(unsigned long w) +{ + /* Let's just say we return the result in the same register as the + input. Saying we clobber the input but can return the result + in another register: + ! __asm__ ("swapnwbr %2\n\tlz %2,%0" + ! : "=r,r" (res), "=r,X" (dummy) : "1,0" (w)); + confuses gcc (sched.c, gcc from cris-dist-1.14). */ + + unsigned long res; + __asm__ ("swapnwbr %0 \n\t" + "lz %0,%0" + : "=r" (res) : "0" (w)); + return res; +} + +static inline unsigned long cris_swapwbrlz(unsigned long w) +{ + unsigned res; + __asm__ ("swapwbr %0 \n\t" + "lz %0,%0" + : "=r" (res) + : "0" (w)); + return res; +} + +/* + * ffz = Find First Zero in word. Undefined if no zero exists, + * so code should check against ~0UL first.. + */ +static inline unsigned long ffz(unsigned long w) +{ + return cris_swapnwbrlz(w); +} + +/** + * __ffs - find first bit in word. + * @word: The word to search + * + * Undefined if no bit exists, so code should check against 0 first. + */ +static inline unsigned long __ffs(unsigned long word) +{ + return cris_swapnwbrlz(~word); +} + +/** + * ffs - find first bit set + * @x: the word to search + * + * This is defined the same way as + * the libc and compiler builtin ffs routines, therefore + * differs in spirit from the above ffz (man ffs). + */ + +static inline unsigned long kernel_ffs(unsigned long w) +{ + return w ? cris_swapwbrlz (w) + 1 : 0; +} + +#endif |