diff --git a/internal/sm2ec/p256_asm_arm64.s b/internal/sm2ec/p256_asm_arm64.s
index 164a305..6ee0ff8 100644
--- a/internal/sm2ec/p256_asm_arm64.s
+++ b/internal/sm2ec/p256_asm_arm64.s
@@ -569,7 +569,7 @@ ordSqrLoop:
 	// Last reduction step
 	MUL	acc3, hlp1, hlp0
 
-	MUL	const0, hlp1, t0
+	MUL	const0, hlp0, t0
 	ADDS	t0, acc3, acc3
 	UMULH	const0, hlp0, t1
 
@@ -650,7 +650,7 @@ TEXT ·p256OrdMul(SB),NOSPLIT,$0
 	// First reduction step
 	MUL	acc0, hlp1, hlp0
 
-	MUL	const0, hlp1, t0
+	MUL	const0, hlp0, t0
 	ADDS	t0, acc0, acc0
 	UMULH	const0, hlp0, t1
 
@@ -697,7 +697,7 @@ TEXT ·p256OrdMul(SB),NOSPLIT,$0
 	// Second reduction step
 	MUL	acc1, hlp1, hlp0
 
-	MUL	const0, hlp1, t0
+	MUL	const0, hlp0, t0
 	ADDS	t0, acc1, acc1
 	UMULH	const0, hlp0, t1
 
@@ -744,7 +744,7 @@ TEXT ·p256OrdMul(SB),NOSPLIT,$0
 	// Third reduction step
 	MUL	acc2, hlp1, hlp0
 
-	MUL	const0, hlp1, t0
+	MUL	const0, hlp0, t0
 	ADDS	t0, acc2, acc2
 	UMULH	const0, hlp0, t1
 
@@ -791,7 +791,7 @@ TEXT ·p256OrdMul(SB),NOSPLIT,$0
 	// Last reduction step
 	MUL	acc3, hlp1, hlp0
 
-	MUL	const0, hlp1, t0
+	MUL	const0, hlp0, t0
 	ADDS	t0, acc3, acc3
 	UMULH	const0, hlp0, t1