ecf2d82159
* Synchronize the code of the rt mart branch to the master branch.
* TTY device
* Add lwP code from rt-smart
* Add vnode in DFS, but DFS will be re-write for rt-smart
* There are three libcpu for rt-smart:
* arm/cortex-a, arm/aarch64
* riscv64
Co-authored-by: Rbb666 <zhangbingru@rt-thread.com>
Co-authored-by: zhkag <zhkag@foxmail.com>
42 lines
720 B
C
42 lines
720 B
C
#ifndef _ASM_GENERIC_BITOPS_FFS_H_
|
|
#define _ASM_GENERIC_BITOPS_FFS_H_
|
|
|
|
/**
|
|
* 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 int ffs(int x)
|
|
{
|
|
int r = 1;
|
|
|
|
if (!x)
|
|
return 0;
|
|
if (!(x & 0xffff)) {
|
|
x >>= 16;
|
|
r += 16;
|
|
}
|
|
if (!(x & 0xff)) {
|
|
x >>= 8;
|
|
r += 8;
|
|
}
|
|
if (!(x & 0xf)) {
|
|
x >>= 4;
|
|
r += 4;
|
|
}
|
|
if (!(x & 3)) {
|
|
x >>= 2;
|
|
r += 2;
|
|
}
|
|
if (!(x & 1)) {
|
|
x >>= 1;
|
|
r += 1;
|
|
}
|
|
return r;
|
|
}
|
|
|
|
#endif /* _ASM_GENERIC_BITOPS_FFS_H_ */
|