BaseMemoryLibSse2: Take advantage of write combining buffers

The current SSE2 implementation of the ZeroMem(), SetMem(),
SetMem16(), SetMem32 and SetMem64 functions is writing 16 bytes per 16
bytes. It hurts the performances so bad that this is even slower than
a simple 'rep stos' (4% slower) in regular DRAM.

To take full advantages of the 'movntdq' instruction it is better to
"queue" a total of 64 bytes in the write combining buffers.  This
patch implement such a change.  Below is a table where I measured
(with 'rdtsc') the time to write an entire 100MB RAM buffer. These
functions operate almost two times faster.

| Function | Arch | Untouched | 64 bytes | Result |
|----------+------+-----------+----------+--------|
| ZeroMem  | Ia32 |  17765947 |  9136062 | 1.945x |
| ZeroMem  | X64  |  17525170 |  9233391 | 1.898x |
| SetMem   | Ia32 |  17522291 |  9137272 | 1.918x |
| SetMem   | X64  |  17949261 |  9176978 | 1.956x |
| SetMem16 | Ia32 |  18219673 |  9372062 | 1.944x |
| SetMem16 | X64  |  17523331 |  9275184 | 1.889x |
| SetMem32 | Ia32 |  18495036 |  9273053 | 1.994x |
| SetMem32 | X64  |  17368864 |  9285885 | 1.870x |
| SetMem64 | Ia32 |  18564473 |  9241362 | 2.009x |
| SetMem64 | X64  |  17506951 |  9280148 | 1.886x |

Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>

MdePkg/Library/BaseMemoryLibSse2/X64/SetMem16.nasm

@@ -33,7 +33,7 @@ ASM_PFX(InternalMemSetMem16):
     mov     r9, rdi
     xor     rcx, rcx
     sub     rcx, rdi
-    and     rcx, 15
+    and     rcx, 63
     mov     rax, r8
     jz      .0
     shr     rcx, 1
@@ -43,15 +43,18 @@ ASM_PFX(InternalMemSetMem16):
     rep     stosw
 .0:
     mov     rcx, rdx
-    and     edx, 7
-    shr     rcx, 3
+    and     edx, 31
+    shr     rcx, 5
     jz      @SetWords
     movd    xmm0, eax
     pshuflw xmm0, xmm0, 0
     movlhps xmm0, xmm0
 .1:
     movntdq [rdi], xmm0
-    add     rdi, 16
+    movntdq [rdi + 16], xmm0
+    movntdq [rdi + 32], xmm0
+    movntdq [rdi + 48], xmm0
+    add     rdi, 64
     loop    .1
     mfence
 @SetWords: