[ion] 23887: - Fix a bug in RtlFillMemory. - Fix overlap check comments.

Author: ion
Date: Sat Sep  2 20:36:48 2006
New Revision: 23887

URL: http://svn.reactos.org/svn/reactos?rev=23887&view=rev
Log:
- Fix a bug in RtlFillMemory.
- Fix overlap check comments.

Modified:
    trunk/reactos/lib/rtl/i386/rtlmem.s

Modified: trunk/reactos/lib/rtl/i386/rtlmem.s
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/lib/rtl/i386/rtlmem.s?rev=2...
==============================================================================
--- trunk/reactos/lib/rtl/i386/rtlmem.s (original)
+++ trunk/reactos/lib/rtl/i386/rtlmem.s Sat Sep  2 20:36:48 2006
@@ -110,7 +110,7 @@
     /* Get pattern */
     mov al, [esp+16]
     mov ah, al
-    shr eax, 16
+    shl eax, 16
     mov al, [esp+16]
     mov ah, al

@@ -227,7 +227,7 @@
     mov ecx, [esp+20]
     cld

-    /* Check for overlap */
+    /* Check if the destination is higher (or equal) */
     cmp esi, edi
     jbe Overlap

@@ -252,15 +252,16 @@
     rep stosb

DoneMove:
+    /* Restore volatiles */
     pop edi
     pop esi
     ret 12

Overlap:
-    /* Avoid full overlap */
+    /* Don't copy if they're equal */
     jz DoneMove

-    /* Remove overlap */
+    /* Compare pointer distance with given length and check for overlap */
     mov eax, edi
     sub eax, esi
     cmp ecx, eax
@@ -269,7 +270,7 @@
     /* Set direction flag for backward move */
     std

-    /* Can only move some bytes, calculate how many */
+    /* Copy byte-by-byte the non-overlapping distance */
     add esi, ecx
     add edi, ecx
     dec esi