diff --git a/MFMM.md b/MFMM.md
index a73a12b..76e7d03 100644
--- a/MFMM.md
+++ b/MFMM.md
@@ -63,7 +63,7 @@ acc0, acc1, acc2, acc3, acc4, acc5是64位寄存器
 	UMULH	acc0, const1, acc0    // acc0 = H(acc0 * p3)
 	ADCS	t0, acc2              // (carry2, acc2) = carry1 + acc2 + H(acc0 * 2^32)
 	ADCS	t1, acc3              // (carry3, acc3) = carry2 + acc3 + L(acc0 * p3)
-	ADC	$0, acc0              // acc0 = carry3 + H(acc0 * p3), why? 猜测后续有优化
+	ADC	$0, acc0              // acc0 = carry3 + H(acc0 * p3), arm64的实现，((acc0, acc4), acc3, acc2, acc1)表示第一次reduction的结果, 不像amd64那样使用（acc5, acc4, acc3, acc2, acc1）。
 
     SM2曲线
     p = 0x fffffffeffffffff ffffffffffffffff ffffffff00000000 ffffffffffffffff