memcmp: Compress lines

(cherry picked from commit f90d5d0)
Signed-off-by: LIU Hao <[email protected]>

mcfgthread/memcmp.c

@@ -17,10 +17,10 @@ int
 __cdecl
 memcmp(const void* src, const void* cmp, size_t size)
   {
-    int diff = 0;
+    int diff;
     const uint8_t* psrc = src;
     const uint8_t* pcmp = cmp;
-    size_t dp = size;
+    size_t t = size;
 
 #if defined __i386__ || defined __amd64__
     /* Perform string comparison with hardware.  */
@@ -30,14 +30,13 @@ memcmp(const void* src, const void* cmp, size_t size)
       "setnz al; "      /* EAX = 0 if equal, 1 if less or greater  */
       "sbb ecx, ecx; "  /* ECX = 0 if equal or greater, -1 if less  */
       "or eax, ecx; "
-      : "=a"(diff), "+S"(psrc), "+D"(pcmp), "+c"(dp) :
+      : "=a"(diff), "+S"(psrc), "+D"(pcmp), "+c"(t) :
       : "memory");
 #else
     /* Get the number of matching bytes. If there is a mismatch, get the
      * difference between the first pair of mismatching bytes.  */
-    dp = RtlCompareMemory(psrc, pcmp, dp);
-    if(dp != size)
-      diff = psrc[dp] - pcmp[dp];
+    t = RtlCompareMemory(psrc, pcmp, t);
+    diff = (t == size) ? 0 : (psrc[t] - pcmp[t]);
 #endif
     return diff;
   }