https://dyncall.org/pub/dyncall/dyncall/rev/d982a00c2177

Index: dyncall/dyncall_call_ppc64.S
--- dyncall/dyncall_call_ppc64.S.orig
+++ dyncall/dyncall_call_ppc64.S
@@ -116,7 +116,7 @@ ENTRY_C(dcCall_ppc64)
 
 	srwi r5,r5,3            /* r5 = size in double words */
 
-	cmpi cr0,r5,0           /* if stacksize != 0 .. */
+	cmpi cr0,0,r5,0         /* if stacksize != 0 .. */
 	beq  cr0,.copy_done
 
 	mtctr r5                /* copy loop */