74 lines
1.8 KiB
C
74 lines
1.8 KiB
C
|
/* 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.
|
||
|
*/
|
||
|
extern 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;
|
||
|
}
|
||
|
|
||
|
extern 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..
|
||
|
*/
|
||
|
extern 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.
|
||
|
*/
|
||
|
extern __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).
|
||
|
*/
|
||
|
|
||
|
extern inline unsigned long kernel_ffs(unsigned long w)
|
||
|
{
|
||
|
return w ? cris_swapwbrlz (w) + 1 : 0;
|
||
|
}
|
||
|
|
||
|
#endif
|