diff --git a/headers/posix/arch/x86_64/arch_setjmp.h b/headers/posix/arch/x86_64/arch_setjmp.h
index 2d8f39ec4d..e1043da0c3 100644
--- a/headers/posix/arch/x86_64/arch_setjmp.h
+++ b/headers/posix/arch/x86_64/arch_setjmp.h
@@ -6,6 +6,6 @@
 #define _ARCH_SETJMP_H_
 
 
-typedef int __jmp_buf[8];
+typedef unsigned long __jmp_buf[8];
 
 #endif	/* _ARCH_SETJMP_H_ */
diff --git a/src/system/libroot/posix/arch/x86_64/sigsetjmp.S b/src/system/libroot/posix/arch/x86_64/sigsetjmp.S
index 25bef80a68..0e7b5afc77 100644
--- a/src/system/libroot/posix/arch/x86_64/sigsetjmp.S
+++ b/src/system/libroot/posix/arch/x86_64/sigsetjmp.S
@@ -31,7 +31,7 @@ FUNCTION_END(setjmp)
 /* int setjmp(jmp_buf buffer) */
 FUNCTION(setjmp):
 	// Jump to sigsetjmp with a zero saveMask.
-	xorl	%edi, %edi
+	xorl	%esi, %esi
 	jmp		sigsetjmp
 FUNCTION_END(setjmp)