mirror of
https://github.com/RIOT-OS/RIOT.git
synced 2025-12-22 04:53:50 +01:00
61 lines
1.1 KiB
C
61 lines
1.1 KiB
C
/*
|
|
* SPDX-FileCopyrightText: 2016 Eistec AB
|
|
* SPDX-License-Identifier: LGPL-2.1-only
|
|
*/
|
|
|
|
/**
|
|
* @ingroup cpu
|
|
* @{
|
|
*
|
|
* @file
|
|
* @brief MSPGCC supplemental functions
|
|
*
|
|
* @author Joakim Nohlgård <joakim.nohlgard@eistec.se
|
|
*
|
|
* @}
|
|
*/
|
|
|
|
#ifdef __MSPGCC__
|
|
|
|
/* internal GCC type for "half integer" (16 bit) */
|
|
/* See also:
|
|
* http://stackoverflow.com/questions/4559025/what-does-gcc-attribute-modexx-actually-do
|
|
* http://www.delorie.com/gnu/docs/gcc/gccint_53.html
|
|
*/
|
|
typedef unsigned int UHItype __attribute__ ((mode (HI)));
|
|
|
|
/**
|
|
* @brief Count leading zeros
|
|
*
|
|
* Naive implementation
|
|
*/
|
|
int __clzhi2(UHItype x)
|
|
{
|
|
int i = 0;
|
|
for (UHItype mask = (1 << 15); mask != 0; mask >>= 1) {
|
|
if (x & mask) {
|
|
return i;
|
|
}
|
|
++i;
|
|
}
|
|
return i; /* returns 16 if x == 0 */
|
|
}
|
|
|
|
/**
|
|
* @brief Count trailing zeros
|
|
*
|
|
* Naive implementation
|
|
*/
|
|
int __ctzhi2(UHItype x)
|
|
{
|
|
int i = 0;
|
|
for (UHItype mask = 1; mask != 0; mask <<= 1) {
|
|
if (x & mask) {
|
|
return i;
|
|
}
|
|
++i;
|
|
}
|
|
return i; /* returns 16 if x == 0 */
|
|
}
|
|
#endif /* __MSPGCC__ */
|