Index: lib/libc/arch/arm/genassym.cf
===================================================================
RCS file: /cvsroot/src/lib/libc/arch/arm/genassym.cf,v
retrieving revision 1.1
diff -u -p -u -r1.1 genassym.cf
--- lib/libc/arch/arm/genassym.cf	27 Sep 2012 11:20:20 -0000	1.1
+++ lib/libc/arch/arm/genassym.cf	30 Apr 2013 10:42:15 -0000
@@ -32,5 +32,6 @@
 include <sys/types.h>
 include <ucontext.h>
 
+define _UC_REGS_R0	offsetof(ucontext_t, uc_mcontext.__gregs[_REG_R0])
 define _UC_REGS_SP	offsetof(ucontext_t, uc_mcontext.__gregs[_REG_SP])
 define _UC_REGS_PC	offsetof(ucontext_t, uc_mcontext.__gregs[_REG_PC])
Index: lib/libc/arch/arm/gen/swapcontext.S
===================================================================
RCS file: /cvsroot/src/lib/libc/arch/arm/gen/swapcontext.S,v
retrieving revision 1.9
diff -u -p -u -r1.9 swapcontext.S
--- lib/libc/arch/arm/gen/swapcontext.S	28 Nov 2012 02:18:24 -0000	1.9
+++ lib/libc/arch/arm/gen/swapcontext.S	30 Apr 2013 10:42:15 -0000
@@ -44,6 +44,8 @@ ENTRY(swapcontext)
 	add	sp, sp, #4
 	ldmfd	sp!, {r0-r1, lr}
 	RETc(ne)
+	mov	ip, #0
+	str	ip, [r0, #_UC_REGS_R0]
 	str	sp, [r0, #_UC_REGS_SP]	/* Adjust saved SP. */
 	str	lr, [r0, #_UC_REGS_PC]	/* Adjust saved PC. */
 #ifdef SOFTFLOAT