commit 81ba5c301ffeff2c7b5f8cc1030b4a678ff63d27
Author:     Roman Fomin <rfomin@gmail.com>
AuthorDate: Tue Nov 7 15:41:48 2023 +0700
Commit:     GitHub <noreply@github.com>
CommitDate: Tue Nov 7 09:41:48 2023 +0100

    Increase default heap size for 64-bit build (#1635)
---
 src/i_system.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/i_system.c b/src/i_system.c
index dae2107c..dba35903 100644
--- a/src/i_system.c
+++ b/src/i_system.c
@@ -134,7 +134,7 @@ byte *I_ZoneBase (int *size)
     // @category obscure
     // @arg <mb>
     //
-    // Specify the heap size, in MiB (default 16).
+    // Specify the heap size, in MiB.
     //

     p = M_CheckParmWithArgs("-mb", 1);
@@ -146,7 +146,21 @@ byte *I_ZoneBase (int *size)
     }
     else
     {
-        default_ram = DEFAULT_RAM;
+        // Because of the 8-byte pointer size in a 64-bit build, the default
+        // heap size (16 MiB) is insufficient compared to a 32-bit build. For
+        // example, the Alien Vendetta avm62402.lmp demo completes successfully
+        // on a 32-bit build, but terminates with an out of memory error on a
+        // 64-bit build. Therefore, to maintain consistency with a 32-bit
+        // build, the heap size should be increased.
+
+        if (sizeof(void *) == 8)
+        {
+            default_ram = DEFAULT_RAM * 2;
+        }
+        else
+        {
+            default_ram = DEFAULT_RAM;
+        }
         min_ram = MIN_RAM;
     }