diff options
Diffstat (limited to 'libcpu')
| -rw-r--r-- | libcpu/arm/cortex-r4/cpu.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/libcpu/arm/cortex-r4/cpu.c b/libcpu/arm/cortex-r4/cpu.c index 569f7d0c29..3aa7cd35de 100644 --- a/libcpu/arm/cortex-r4/cpu.c +++ b/libcpu/arm/cortex-r4/cpu.c @@ -39,4 +39,17 @@ void rt_hw_cpu_shutdown() while (1); } +#ifdef RT_USING_CPU_FFS +int __rt_ffs(int value) +{ + if (value == 0) + return value; + + __asm(" rsb r1, r0, #0"); + __asm(" and r1, r1, r0"); + __asm(" clz r1, r1"); + __asm(" rsb r0, r1, #32"); +} +#endif + /*@}*/ |