diff --git a/core/cpu/x86/64/64.factor b/core/cpu/x86/64/64.factor
index 2216445e96..cb1fdc85b8 100755
--- a/core/cpu/x86/64/64.factor
+++ b/core/cpu/x86/64/64.factor
@@ -13,8 +13,8 @@ PREDICATE: x86-backend amd64-backend
 M: amd64-backend ds-reg R14 ;
 M: amd64-backend rs-reg R15 ;
 M: amd64-backend stack-reg RSP ;
-M: x86-backend xt-reg RCX ;
-M: x86-backend stack-save-reg RSI ;
+M: amd64-backend xt-reg RCX ;
+M: amd64-backend stack-save-reg RSI ;
 
 M: temp-reg v>operand drop RBX ;