1 files changed, 15 insertions, 4 deletions
diff --git a/MdePkg/Library/BaseMemoryLibSse2/X64/SetMem64.nasm b/MdePkg/Library/BaseMemoryLibSse2/X64/SetMem64.nasm
index d4f740e9d474..bff2cf46504e 100644
--- a/MdePkg/Library/BaseMemoryLibSse2/X64/SetMem64.nasm
+++ b/MdePkg/Library/BaseMemoryLibSse2/X64/SetMem64.nasm
@@ -37,17 +37,28 @@ ASM_PFX(InternalMemSetMem64):
     add     rdx, 8
     dec     rcx
 .0:
-    shr     rcx, 1
+    push    rbx
+    mov     rbx, rcx
+    and     rbx, 7
+    shr     rcx, 3
     jz      @SetQwords
     movlhps xmm0, xmm0
 .1:
     movntdq [rdx], xmm0
-    lea     rdx, [rdx + 16]
+    movntdq [rdx + 16], xmm0
+    movntdq [rdx + 32], xmm0
+    movntdq [rdx + 48], xmm0
+    lea     rdx, [rdx + 64]
     loop    .1
     mfence
 @SetQwords:
-    jnc     .2
-    mov     [rdx], r8
+    push    rdi
+    mov     rcx, rbx
+    mov     rax, r8
+    mov     rdi, rdx
+    rep     stosq
+    pop     rdi
 .2:
+    pop rbx
     ret