diff --git a/SM2-WWMM-(2).md b/SM2-WWMM-(2).md
index 8d0f568..1f4f237 100644
--- a/SM2-WWMM-(2).md
+++ b/SM2-WWMM-(2).md
@@ -106,8 +106,10 @@ $t_0=t_0 - a_1$
   MOVQ acc0, DX           \
   SHLQ $32, AX            \  // AX = L(acc0 * 2^32), low part
   SHRQ $32, DX            \  // DX = H(acc0 * 2^32), high part
-  \// calculate the negative part: [1, -0x100000000, 0, -0x100000000] * acc0 + [0, acc3, acc2, acc1]
-  \ //[acc0, acc3, acc2, acc1] - [0, 0x100000000, 0, 0x100000000] * acc0
+  \// calculate the negative part: 
+  \//[1, -0x100000000, 0, -0x100000000] * acc0 + [0, acc3, acc2, acc1]
+  \//[acc0, acc3, acc2, acc1] - [0, 0x100000000, 0, 0x100000000] * acc0
+  \//[acc0, acc3, acc2, acc1] - [acc0>>32, acc0<<32, acc0>>32, acc0<<32]
   SUBQ AX, acc1            \ 
   SBBQ DX, acc2            \
   SBBQ AX, acc3            \