BUGFIX: battle scripts (#1436)

src/battle_ai_script_commands.c

@@ -1761,7 +1761,11 @@ static void Cmd_if_cant_faint(void)
 
     gBattleMoveDamage = gBattleMoveDamage * AI_THINKING_STRUCT->simulatedRNG[AI_THINKING_STRUCT->movesetIndex] / 100;
 
-    // This macro is missing the damage 0 = 1 assumption.
+#ifdef BUGFIX
+    // Moves always do at least 1 damage.
+    if (gBattleMoveDamage == 0)
+        gBattleMoveDamage = 1;
+#endif
 
     if (gBattleMons[gBattlerTarget].hp > gBattleMoveDamage)
         gAIScriptPtr = T1_READ_PTR(gAIScriptPtr + 1);
@@ -2019,18 +2023,24 @@ static void Cmd_if_holds_item(void)
 {
     u8 battlerId = BattleAI_GetWantedBattler(gAIScriptPtr[1]);
     u16 item;
-    u8 var1, var2;
+    u8 itemLo, itemHi;
 
     if ((battlerId & BIT_SIDE) == (sBattler_AI & BIT_SIDE))
         item = gBattleMons[battlerId].item;
     else
         item = BATTLE_HISTORY->itemEffects[battlerId];
 
-    // UB: doesn't properly read an unaligned u16
+    itemHi = gAIScriptPtr[2];
-    var2 = gAIScriptPtr[2];
+    itemLo = gAIScriptPtr[3];
-    var1 = gAIScriptPtr[3];
 
-    if ((var1 | var2) == item)
+#ifdef BUGFIX
+    // This bug doesn't affect the vanilla game because this script command
+    // is only used to check ITEM_PERSIM_BERRY, whose high byte happens to
+    // be 0.
+    if (((itemHi << 8) | itemLo) == item)
+#else
+    if ((itemLo | itemHi) == item)
+#endif
         gAIScriptPtr = T1_READ_PTR(gAIScriptPtr + 4);
     else
         gAIScriptPtr += 8;

src/battle_script_commands.c

@@ -3357,7 +3357,7 @@ static void Cmd_getexp(void)
                     // get exp getter battlerId
                     if (gBattleTypeFlags & BATTLE_TYPE_DOUBLE)
                     {
-                        if (!(gBattlerPartyIndexes[2] != gBattleStruct->expGetterMonId) && !(gAbsentBattlerFlags & gBitTable[2]))
+                        if (gBattlerPartyIndexes[2] == gBattleStruct->expGetterMonId && !(gAbsentBattlerFlags & gBitTable[2]))
                             gBattleStruct->expGetterBattlerId = 2;
                         else
                         {
@@ -3431,14 +3431,13 @@ static void Cmd_getexp(void)
                     gBattleMons[0].maxHP = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_MAX_HP);
                     gBattleMons[0].attack = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_ATK);
                     gBattleMons[0].defense = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_DEF);
-                    // Why is this duplicated?
+                    // Speed is duplicated, likely due to a copy-paste error.
                     gBattleMons[0].speed = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_SPEED);
                     gBattleMons[0].speed = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_SPEED);
-
                     gBattleMons[0].spAttack = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_SPATK);
                     gBattleMons[0].spDefense = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_SPDEF);
                 }
-                // What is else if?
+
                 if (gBattlerPartyIndexes[2] == gBattleStruct->expGetterMonId && gBattleMons[2].hp && (gBattleTypeFlags & BATTLE_TYPE_DOUBLE))
                 {
                     gBattleMons[2].level = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_LEVEL);
@@ -3446,10 +3445,13 @@ static void Cmd_getexp(void)
                     gBattleMons[2].maxHP = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_MAX_HP);
                     gBattleMons[2].attack = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_ATK);
                     gBattleMons[2].defense = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_DEF);
-                    // Duplicated again, but this time there's no Sp Defense
                     gBattleMons[2].speed = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_SPEED);
+                    // Speed is duplicated again, but Special Defense is missing.
+#ifdef BUGFIX
+                    gBattleMons[2].spDefense = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_SPDEF);
+#else
                     gBattleMons[2].speed = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_SPEED);
-
+#endif
                     gBattleMons[2].spAttack = GetMonData(&gPlayerParty[gBattleStruct->expGetterMonId], MON_DATA_SPATK);
                 }
                 gBattleScripting.getexpState = 5;
@@ -6168,7 +6170,13 @@ static void Cmd_recordlastability(void)
 {
     gActiveBattler = GetBattlerForBattleScript(gBattlescriptCurrInstr[1]);
     RecordAbilityBattle(gActiveBattler, gLastUsedAbility);
-    gBattlescriptCurrInstr += 1; // UB: Should be + 2, one byte for command and one byte for battlerId argument.
+
+#ifdef BUGFIX
+    // This command occupies two bytes (one for the command id, and one for the battler id parameter).
+    gBattlescriptCurrInstr += 2;
+#else
+    gBattlescriptCurrInstr += 1;
+#endif
 }
 
 void BufferMoveToLearnIntoBattleTextBuff2(void)