From f388d888518486676931e0fc3bd915fbb8b338e3 Mon Sep 17 00:00:00 2001
From: alexey.lysiuk
Date: Sat, 10 May 2014 15:50:44 +0300
Subject: hexen: Fix desync of demo1 on some platforms/compilers

Official release of Hexen's source code relies on unspecified behavior the in order of function's argument evaluation, see ISO-IEC 9899-1999, [6.5.2.2.10]
P_Random() are called in different parameters of P_SpawnMobj() within A_LeafSpawn()
---
 src/hexen/a_action.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

(limited to 'src')

diff --git a/src/hexen/a_action.c b/src/hexen/a_action.c
index 3100a074..e25b4f84 100644
--- a/src/hexen/a_action.c
+++ b/src/hexen/a_action.c
@@ -295,10 +295,15 @@ void A_LeafSpawn(mobj_t * actor)
 
     for (i = (P_Random() & 3) + 1; i; i--)
     {
-        mo = P_SpawnMobj(actor->x + ((P_Random() - P_Random()) << 14),
-                         actor->y + ((P_Random() - P_Random()) << 14),
-                         actor->z + (P_Random() << 14),
-                         MT_LEAF1 + (P_Random() & 1));
+        // Official release of Hexen's source code relies on unspecified behavior
+        // the in order of function's argument evaluation,
+        // see ISO-IEC 9899-1999, [6.5.2.2.10]
+        mobjtype_t type = MT_LEAF1 + (P_Random() & 1);
+        fixed_t z = actor->z + (P_Random() << 14);
+        fixed_t y = actor->y + ((P_Random() - P_Random()) << 14);
+        fixed_t x = actor->x + ((P_Random() - P_Random()) << 14);
+
+        mo = P_SpawnMobj(x, y, z, type);
         if (mo)
         {
             P_ThrustMobj(mo, actor->angle, (P_Random() << 9) + 3 * FRACUNIT);
-- 
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