* optimized align() so it no longer contains any branches which

    are undecidable at compile time
  + basic test for align() function


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@9674 3ad0048d-3df7-0310-abae-a5850022a9f2

2 files changed, 31 insertions, 8 deletions

diff --git a/rtl/inc/generic.inc b/rtl/inc/generic.inc
index 5f2c1d7d6e..1bb2134df5 100644
--- a/rtl/inc/generic.inc
+++ b/rtl/inc/generic.inc
@@ -1507,20 +1507,20 @@ procedure inclocked(var l:int64);
 
 
 function align(addr : PtrUInt;alignment : PtrUInt) : PtrUInt;{$ifdef SYSTEMINLINE}inline;{$endif}
+  var
+    tmp: PtrUInt;
   begin
-    if addr mod alignment<>0 then
-      result:=addr+(alignment-(addr mod alignment))
-    else
-      result:=addr;
+    tmp:=addr+alignment-1;
+    result:=tmp-(tmp mod alignment)
   end;
 
 
 function align(addr : Pointer;alignment : PtrUInt) : Pointer;{$ifdef SYSTEMINLINE}inline;{$endif}
+  var
+    tmp: PtrUInt;
   begin
-    if PtrUInt(addr) mod alignment<>0 then
-      result:=pointer(addr+(alignment-(PtrUInt(addr) mod alignment)))
-    else
-      result:=addr;
+    tmp:=PtrUInt(addr)+alignment-1;
+    result:=pointer(tmp-(tmp mod alignment));
   end;
 
 
diff --git a/tests/test/units/system/talign.pp b/tests/test/units/system/talign.pp
new file mode 100644
index 0000000000..ea39820331
--- /dev/null
+++ b/tests/test/units/system/talign.pp
@@ -0,0 +1,23 @@
+var
+  p: pointer;
+  u: ptruint;
+  i: cardinal;
+begin
+  p:=pointer(1);
+  for i:=0 to 15 do
+    if align(p+i,16)<>pointer(16) then
+      halt(1);
+  p:=pointer(41);
+  for i:=0 to 39 do
+    if align(p+i,40)<>pointer(80) then
+      halt(2);
+
+  u:=1;
+  for i:=0 to 15 do
+    if align(u+i,16)<>16 then
+      halt(3);
+  u:=41;
+  for i:=0 to 39 do
+    if align(u+i,40)<>80 then
+      halt(4);
+end.