Changeset 1822

Timestamp:

Oct 10, 2008, 10:27:37 PM (16 years ago)

Author:

bird

Message:

inlined_memchr: hacked up a 8-byte loop unroll, doesn't by much/anything over the four byte one though so it's disabled.

File:

• trunk/src/kmk/inlined_memchr.h (modified) (3 diffs)

trunk/src/kmk/inlined_memchr.h ¶

@@ -1 +1 @@
 #include <string.h>
+
 #ifdef _MSC_VER
 _inline void *
@@ -9 +10 @@
     register const unsigned int   uch = (unsigned)ch;
     register const unsigned char *pb = (const unsigned char *)pv;
-#if 1
+#if 0 /* 8-byte loop unroll */
+    while (cb >= 8)
+    {
+        if (*pb == uch)
+            return (unsigned char *)pb;
+        if (pb[1] == uch)
+            return (unsigned char *)pb + 1;
+        if (pb[2] == uch)
+            return (unsigned char *)pb + 2;
+        if (pb[3] == uch)
+            return (unsigned char *)pb + 3;
+        if (pb[4] == uch)
+            return (unsigned char *)pb + 4;
+        if (pb[5] == uch)
+            return (unsigned char *)pb + 5;
+        if (pb[6] == uch)
+            return (unsigned char *)pb + 6;
+        if (pb[7] == uch)
+            return (unsigned char *)pb + 7;
+        cb -= 8;
+        pb += 8;
+    }
+    switch (cb & 7)
+    {
+        case 0:
+            break;
+        case 1:
+            if (*pb == uch)
+                return (unsigned char *)pb;
+            break;
+        case 2:
+            if (*pb == uch)
+                return (unsigned char *)pb;
+            if (pb[1] == uch)
+                return (unsigned char *)pb + 1;
+            break;
+        case 3:
+            if (*pb == uch)
+                return (unsigned char *)pb;
+            if (pb[1] == uch)
+                return (unsigned char *)pb + 1;
+            if (pb[2] == uch)
+                return (unsigned char *)pb + 2;
+            break;
+        case 4:
+            if (*pb == uch)
+                return (unsigned char *)pb;
+            if (pb[1] == uch)
+                return (unsigned char *)pb + 1;
+            if (pb[2] == uch)
+                return (unsigned char *)pb + 2;
+            if (pb[3] == uch)
+                return (unsigned char *)pb + 3;
+            break;
+        case 5:
+            if (*pb == uch)
+                return (unsigned char *)pb;
+            if (pb[1] == uch)
+                return (unsigned char *)pb + 1;
+            if (pb[2] == uch)
+                return (unsigned char *)pb + 2;
+            if (pb[3] == uch)
+                return (unsigned char *)pb + 3;
+            if (pb[4] == uch)
+                return (unsigned char *)pb + 4;
+            break;
+        case 6:
+            if (*pb == uch)
+                return (unsigned char *)pb;
+            if (pb[1] == uch)
+                return (unsigned char *)pb + 1;
+            if (pb[2] == uch)
+                return (unsigned char *)pb + 2;
+            if (pb[3] == uch)
+                return (unsigned char *)pb + 3;
+            if (pb[4] == uch)
+                return (unsigned char *)pb + 4;
+            if (pb[5] == uch)
+                return (unsigned char *)pb + 5;
+            break;
+        case 7:
+            if (*pb == uch)
+                return (unsigned char *)pb;
+            if (pb[1] == uch)
+                return (unsigned char *)pb + 1;
+            if (pb[2] == uch)
+                return (unsigned char *)pb + 2;
+            if (pb[3] == uch)
+                return (unsigned char *)pb + 3;
+            if (pb[4] == uch)
+                return (unsigned char *)pb + 4;
+            if (pb[5] == uch)
+                return (unsigned char *)pb + 5;
+            if (pb[6] == uch)
+                return (unsigned char *)pb + 6;
+            break;
+    }
+
+#elif 1 /* 4 byte loop unroll */
     while (cb >= 4)
     {
@@ -47 +146 @@
     }
 
-#else
+#else /* the basic loop */
     while (cb > 0)
     {