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xtensa: fix find_msb_set() and find_lsb_set()

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find_msb_set logic was wrong. find_lsb_set() is now an inline function.

Change-Id: I2c19540907723589298b2f6af2ce1d68704bf1d7
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2017-01-24 15:33:02 -08:00
commit 73691609b9
1 changed files with 35 additions and 2 deletions
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37
include/arch/xtensa/arch.h
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@ -38,8 +38,41 @@ extern "C" {
#include <arch/xtensa/exc.h>
#define find_lsb_set __builtin_ffs
#define find_msb_set __builtin_clz
/**
*
* @brief find most significant bit set in a 32-bit word
*
* This routine finds the first bit set starting from the most significant bit
* in the argument passed in and returns the index of that bit. Bits are
* numbered starting at 1 from the least significant bit. A return value of
* zero indicates that the value passed is zero.
*
* @return most significant bit set, 0 if @a op is 0
*/
static ALWAYS_INLINE unsigned int find_msb_set(uint32_t op)
{
if (!op)
return 0;
return 32 - __builtin_clz(op);
}
/**
*
* @brief find least significant bit set in a 32-bit word
*
* This routine finds the first bit set starting from the least significant bit
* in the argument passed in and returns the index of that bit. Bits are
* numbered starting at 1 from the least significant bit. A return value of
* zero indicates that the value passed is zero.
*
* @return least significant bit set, 0 if @a op is 0
*/
static ALWAYS_INLINE unsigned int find_lsb_set(uint32_t op)
{
return __builtin_ffs(op);
}
/* internal routine documented in C file, needed by IRQ_CONNECT() macro */
extern void _irq_priority_set(uint32_t irq, uint32_t prio, uint32_t flags);