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cortex-r4: add __rt_ffs

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This commit is contained in:
Grissiom 2013-06-01 02:16:10 +08:00
parent 480ac34445
commit 228a6be077
2 changed files with 14 additions and 0 deletions
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1
bsp/rm48x50/rtconfig.h
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@ -212,6 +212,7 @@
// </section> // </section>
#define RT_VFP_LAZY_STACKING #define RT_VFP_LAZY_STACKING
#define RT_USING_CPU_FFS
// </RDTConfigurator> // </RDTConfigurator>
#endif #endif

13
libcpu/arm/cortex-r4/cpu.c
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@ -39,4 +39,17 @@ void rt_hw_cpu_shutdown()
while (1); 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
/*@}*/ /*@}*/