bitops.h

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/* 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);
}

static inline unsigned long __ffs(unsigned long word)
{
    return cris_swapnwbrlz(~word);
}

static inline unsigned long kernel_ffs(unsigned long w)
{
    return w ? cris_swapwbrlz (w) + 1 : 0;
}

#endif