From 0645c724d1bac953857d16120ee4d1c217714d96 Mon Sep 17 00:00:00 2001
From: Jan Rysavy <janrysavy@users.noreply.github.com>
Date: Tue, 21 Jul 2026 11:35:47 +0200
Subject: [PATCH] Use FillChar for larger debug block fills

---
 FastMM5.pas | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/FastMM5.pas b/FastMM5.pas
index 4d6aa4f..5dd05d3 100644
--- a/FastMM5.pas
+++ b/FastMM5.pas
@@ -4243,6 +4243,14 @@ procedure FillFreedDebugBlockWithDebugPattern(APDebugBlockHeader: PFastMM_DebugB
   LByteOffset := APDebugBlockHeader.UserSize;
   LPUserArea := PByte(APDebugBlockHeader) + CDebugBlockHeaderSize;
 
+  {Use FillChar above the measured crossover and retain the scalar path for smaller blocks.}
+  if LByteOffset >= 40 then
+  begin
+    FillChar(LPUserArea^, LByteOffset, CDebugFillByteFreedBlock);
+    PPointerArray(LPUserArea)[0] := TFastMM_FreedObject;
+    Exit;
+  end;
+
   {Store a pointer to the freed object class if the block is large enough.}
   if LByteOffset >= CTObjectInstanceSize then
   begin
@@ -4290,6 +4298,13 @@ procedure FillAllocatedDebugBlockWithDebugPattern(APDebugBlockHeader: PFastMM_De
   LByteOffset := APDebugBlockHeader.UserSize;
   LPUserArea := PByte(APDebugBlockHeader) + CDebugBlockHeaderSize;
 
+  {Use FillChar above the measured crossover and retain the scalar path for smaller blocks.}
+  if LByteOffset >= 40 then
+  begin
+    FillChar(LPUserArea^, LByteOffset, CDebugFillByteAllocatedBlock);
+    Exit;
+  end;
+
   if LByteOffset and 1 <> 0 then
   begin
     Dec(LByteOffset);