Updated SM2 MFMM (2) (markdown)

SM2-MFMM-(2).md

@@ -616,3 +616,36 @@ $t_5=t_5 - 0$
 加法：9  
 减法：4  
 
+**使用MULXQ**:  
+```asm
+	// First reduction step
+	MOVQ acc0, DX
+	MULXQ p256ordK0<>(SB), t0, AX 
+
+	MOVQ t0, DX
+	MULXQ p256ord<>+0x00(SB), AX, BX
+	ADDQ AX, acc0
+	ADCQ BX, acc1
+
+	MULXQ p256ord<>+0x08(SB), AX, BX
+	ADCQ $0, BX
+	ADDQ AX, acc1
+	ADCQ BX, acc2
+	ADCQ $0, acc3
+	ADCQ t0, acc4
+	ADCQ $0, acc5
+
+	MOVQ t0, AX
+	//MOVQ t0, DX // This is not required due to t0=DX already
+	SHLQ $32, AX
+	SHRQ $32, DX
+		
+	SUBQ t0, acc2
+	SBBQ AX, acc3
+	SBBQ DX, acc4
+	SBBQ $0, acc5
+```
+乘法: 3  
+移位：2    
+加法：8  
+减法：4