diff --git a/tests/checkasm/aarch64/checkasm.S b/tests/checkasm/aarch64/checkasm.S
index 03bd983160..53a2a478dc 100644
--- a/tests/checkasm/aarch64/checkasm.S
+++ b/tests/checkasm/aarch64/checkasm.S
@@ -55,13 +55,13 @@ endconst
 #define CLOBBER_STACK ((8*MAX_ARGS + 15) & ~15)
 
 function checkasm_stack_clobber, export=1
-    mov         x29, sp
+    mov         x3,  sp
     mov         x2,  #CLOBBER_STACK
 1:
     stp         x0,  x1,  [sp, #-16]!
     subs        x2,  x2,  #16
     b.gt        1b
-    mov         sp,  x29
+    mov         sp,  x3
     ret
 endfunc