diff --git a/base14_amd64.go b/base14_amd64.go
index 80675d6..b6c8aa5 100644
--- a/base14_amd64.go
+++ b/base14_amd64.go
@@ -9,7 +9,7 @@ import (
 
 //go:noescape
 //go:nosplit
-func _encode(offset, outlen int, b, encd []byte) (sum uint64, n uint64)
+func _encode(offset int, b, encd []byte) (sum uint64, n uint64)
 
 //go:noescape
 //go:nosplit
@@ -17,10 +17,7 @@ func _decode(offset, outlen int, b, decd []byte)
 
 func encode(offset, outlen int, b, encd []byte) {
 	if movbe {
-		if len(b) == 7 {
-			b = append(b, 0)
-		}
-		sum, n := _encode(offset, outlen, b, encd)
+		sum, n := _encode(offset, b, encd)
 		if offset == 0 {
 			return
 		}
@@ -36,9 +33,6 @@ func encode(offset, outlen int, b, encd []byte) {
 
 func decode(offset, outlen int, b, decd []byte) {
 	if movbe {
-		if offset != 0 && cap(b) == len(b) {
-			b = append(b, make([]byte, 8)...)
-		}
 		_decode(offset, outlen, b, decd)
 	} else {
 		decodeGeneric(offset, outlen, b, decd)
diff --git a/base14_amd64.s b/base14_amd64.s
index 29eadda..f345288 100644
--- a/base14_amd64.s
+++ b/base14_amd64.s
@@ -3,13 +3,12 @@
 
 #include "textflag.h"
 
-// func _encode(offset, outlen int, b, encd []byte) (sum uint64, n uint64)
-TEXT ·_encode(SB), NOSPLIT, $0-81
+// func _encode(offset int, b, encd []byte) (sum uint64, n uint64)
+TEXT ·_encode(SB), NOSPLIT, $0-72
     MOVQ ·offset+0(FP), R10
-    MOVQ ·outlen+8(FP), AX
-    MOVQ ·data+16(FP), DI
-    MOVQ ·dlen+24(FP), R8
-    MOVQ ·encd+40(FP), R9
+    MOVQ ·data+8(FP), DI
+    MOVQ ·dlen+16(FP), R8
+    MOVQ ·encd+32(FP), R9
     XORQ CX, CX
     XORQ SI, SI
     SUBQ $6, R8
@@ -117,8 +116,8 @@ encsav:
     MOVQ $21955383195992142, CX
     ADDQ CX, DX
     SHLQ $3, SI
-    MOVQ DX, ·sum+64(FP)
-    MOVQ SI, ·n+72(FP)
+    MOVQ DX, ·sum+56(FP)
+    MOVQ SI, ·n+64(FP)
 
 encend:
     RET