From 228a6be077a2e2f40e9cbc6f23ed232a8371e7d0 Mon Sep 17 00:00:00 2001
From: Grissiom <chaos.proton@gmail.com>
Date: Sat, 1 Jun 2013 02:16:10 +0800
Subject: [PATCH] cortex-r4: add __rt_ffs

---
 bsp/rm48x50/rtconfig.h     |  1 +
 libcpu/arm/cortex-r4/cpu.c | 13 +++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/bsp/rm48x50/rtconfig.h b/bsp/rm48x50/rtconfig.h
index 86fc630c8..d681ef736 100644
--- a/bsp/rm48x50/rtconfig.h
+++ b/bsp/rm48x50/rtconfig.h
@@ -212,6 +212,7 @@
 // </section>
 
 #define RT_VFP_LAZY_STACKING
+#define RT_USING_CPU_FFS
 // </RDTConfigurator>
 
 #endif
diff --git a/libcpu/arm/cortex-r4/cpu.c b/libcpu/arm/cortex-r4/cpu.c
index 569f7d0c2..3aa7cd35d 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
+
 /*@}*/
-- 
GitLab