diff --git a/src/runtime/mkduff.go b/src/runtime/mkduff.go
index b7f07b5087caf9353cb0adae0c5070177850e425..86521d6d04ad3ad14387697bca21400ba01c850e 100644
--- a/src/runtime/mkduff.go
+++ b/src/runtime/mkduff.go
@@ -179,8 +179,8 @@ func copyARM64(w io.Writer) {
 
 func zeroLOONG64(w io.Writer) {
 	// R0: always zero
-	// R19 (aka REGRT1): ptr to memory to be zeroed
-	// On return, R19 points to the last zeroed dword.
+	// R20: ptr to memory to be zeroed
+	// On return, R20 points to the last zeroed dword.
 	fmt.Fprintln(w, "TEXT runtime·duffzero<ABIInternal>(SB), NOSPLIT|NOFRAME, $0-0")
 	for i := 0; i < 128; i++ {
 		fmt.Fprintln(w, "\tMOVV\tR0, (R20)")