From ef2496f4914c5e1a246c8cf55a3f1fc3540e88ab Mon Sep 17 00:00:00 2001
From: zhanghm18 <142378820+zhanghm18GIT@users.noreply.github.com>
Date: Sun, 26 Jul 2026 23:05:25 +0800
Subject: [PATCH 1/2] Complete HEAPMNG full-range bookkeeping

---
 hooks/HFix4GB.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/hooks/HFix4GB.cpp b/hooks/HFix4GB.cpp
index 5c151181..e98f1645 100644
--- a/hooks/HFix4GB.cpp
+++ b/hooks/HFix4GB.cpp
@@ -1,6 +1,8 @@
 asm(
+  // Allocate one 4-byte map entry for every 4 KiB page in the complete
+  // 32-bit virtual address space: 0x100000 entries * 4 = 0x400000 bytes.
   ".section h0; .set h0,0x957E35;"
-  "PUSH 0x3FF000;"
+  "PUSH 0x400000;"
 
   ".section h1; .set h1,0x915A92;"
   "ADD EAX,EAX;"
@@ -11,4 +13,9 @@ asm(
 
   ".section h2; .set h2,0x915B05;"
   "JMP .-0x73;"
-);
\ No newline at end of file
+
+  // Keep 0x100000 as the one-past-end page index while allowing free
+  // regions in the 3-4 GiB range to coalesce with a right neighbour.
+  ".section h3; .set h3,0x958107;"
+  "CMP EAX,0x100000;"
+);

From a402f341ddb0b09cea67ed115dd7bfe91f87a464 Mon Sep 17 00:00:00 2001
From: zhanghm18 <142378820+zhanghm18GIT@users.noreply.github.com>
Date: Sun, 26 Jul 2026 23:06:55 +0800
Subject: [PATCH 2/2] Document HEAPMNG full-range bookkeeping

---
 changelog.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/changelog.md b/changelog.md
index be9a8470..a5e35d1b 100644
--- a/changelog.md
+++ b/changelog.md
@@ -155,7 +155,7 @@ These don't matter except for other assembly patches
 
 ## Improvements
 
-- Allows to use 4GB on x64
+- Complete HEAPMNG page-map coverage and enable free-region coalescing across the 3-4 GiB range on x64.
 
   - hooks/HFix4GB.cpp