diff --git a/components/lwp/arch/arm/cortex-a/lwp_arch.h b/components/lwp/arch/arm/cortex-a/lwp_arch.h
index 6132ce46d9e8c2310fbea3619df47d46769f10c0..d627632493f529e28b31a500028cce134c88caca 100644
--- a/components/lwp/arch/arm/cortex-a/lwp_arch.h
+++ b/components/lwp/arch/arm/cortex-a/lwp_arch.h
@@ -30,7 +30,7 @@ extern "C" {
 
 rt_inline unsigned long rt_hw_ffz(unsigned long x)
 {
-    return __builtin_ffsll(~x) - 1;
+    return __builtin_ffsl(~x) - 1;
 }
 
 rt_inline void icache_invalid_all(void)
diff --git a/components/lwp/arch/risc-v/rv64/lwp_arch.h b/components/lwp/arch/risc-v/rv64/lwp_arch.h
index cb7d8831358974f15bc52878170586a8a3162fc4..9e12aa5ba70463413941b4c0e7db9f12de8c420e 100644
--- a/components/lwp/arch/risc-v/rv64/lwp_arch.h
+++ b/components/lwp/arch/risc-v/rv64/lwp_arch.h
@@ -53,7 +53,7 @@ rt_mmu_info* arch_kernel_get_mmu_info(void);
 
 rt_inline unsigned long rt_hw_ffz(unsigned long x)
 {
-    return __builtin_ffsll(~x) - 1;
+    return __builtin_ffsl(~x) - 1;
 }
 
 rt_inline void icache_invalid_all(void)
diff --git a/components/lwp/arch/x86/i386/lwp_arch.h b/components/lwp/arch/x86/i386/lwp_arch.h
index 6d15aebcd1be5f61a8333f546514c386bdd5c03b..f9a56ca3f5f52ee716e829a945492a7991c3ffb3 100644
--- a/components/lwp/arch/x86/i386/lwp_arch.h
+++ b/components/lwp/arch/x86/i386/lwp_arch.h
@@ -37,7 +37,7 @@ void lwp_signal_do_return(rt_hw_stack_frame_t *frame);
         
 rt_inline unsigned long rt_hw_ffz(unsigned long x)
 {
-    return __builtin_ffsll(~x) - 1;
+    return __builtin_ffsl(~x) - 1;
 }
 
 #ifdef __cplusplus
diff --git a/libcpu/aarch64/common/cpu_gcc.S b/libcpu/aarch64/common/cpu_gcc.S
index a1029906bf362be58f1c164dfbfe170f092045f9..445c104dcea7a50697a5de4514d75d7783814999 100644
--- a/libcpu/aarch64/common/cpu_gcc.S
+++ b/libcpu/aarch64/common/cpu_gcc.S
@@ -86,6 +86,9 @@ rt_cpu_vector_set_base:
     RET
 
 
+/**
+ * unsigned long rt_hw_ffz(unsigned long x)
+ */
 .global rt_hw_ffz
 rt_hw_ffz:
     mvn x1, x0