diff --git a/base64_arm64.go b/base64_arm64.go
index bd269d3..febf0e9 100644
--- a/base64_arm64.go
+++ b/base64_arm64.go
@@ -3,9 +3,23 @@
 
 package base64
 
+var dencodeStdLut1 = [128]byte{
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
+	255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63,
+	52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255, 255, 255, 255, 255,
+	0, 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,
+	14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255,
+	255, 255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
+	40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 255, 255, 255, 255,
+}
+
 //go:noescape
 func encodeAsm(dst, src []byte, lut *[64]byte) int
 
+//go:noescape
+func decodeAsm(dst, src []byte, lut *[128]byte) int
+
 func encode(enc *Encoding, dst, src []byte) {
 	if len(src) >= 48 {
 		encoded := encodeAsm(dst, src, &enc.encode)
diff --git a/base64_arm64.s b/base64_arm64.s
index f6a4e7f..6000e57 100644
--- a/base64_arm64.s
+++ b/base64_arm64.s
@@ -53,3 +53,32 @@ loop:
 done:
 	MOVD R5, ret+56(FP)
 	RET
+
+//func decodeAsm(dst, src []byte, lut *[128]byte) int
+TEXT ·decodeAsm(SB),NOSPLIT,$0
+	MOVD dst_base+0(FP), R0
+	MOVD src_base+24(FP), R1
+	MOVD src_len+32(FP), R2
+	MOVD lut+48(FP), R3
+
+	VLD1.P 64(R3), [V8.B16, V9.B16, V10.B16, V11.B16]
+	VLD1 (R3), [V12.B16, V13.B16, V14.B16, V15.B16]
+	MOVD $0x63, R4
+	VDUP R4, V7.B16
+
+loop:
+	CMP $64, R2
+	BLT done
+
+	VLD4.P 64(R1), [V0.B16, V1.B16, V2.B16, V3.B16]
+	VUQSUB V7.B16, V0.B16, V16.B16
+	VUQSUB V7.B16, V1.B16, V17.B16
+	VUQSUB V7.B16, V2.B16, V18.B16
+	VUQSUB V7.B16, V3.B16, V19.B16
+
+	SUB $64, R2
+	B loop
+
+done:
+	MOVD R2, ret+56(FP)
+	RET