Port script_movement

13 files changed, 257 insertions, 629 deletions

diff --git a/asm/script_movement.s b/asm/script_movement.s
deleted file mode 100644
index 7b3a70a25..000000000
--- a/asm/script_movement.s
+++ /dev/null
@@ -1,602 +0,0 @@
-	.include "asm/macros.inc"
-	.include "constants/constants.inc"
-
-	.syntax unified
-
-	.text
-
-	thumb_func_start ScriptMovement_StartObjectMovementScript
-ScriptMovement_StartObjectMovementScript: @ 8097434
-	push {r4,lr}
-	sub sp, 0x4
-	adds r4, r3, 0
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, 24
-	lsrs r1, 24
-	lsls r2, 24
-	lsrs r2, 24
-	mov r3, sp
-	bl TryGetObjectEventIdByLocalIdAndMap
-	lsls r0, 24
-	cmp r0, 0
-	beq _08097456
-	movs r0, 0x1
-	b _0809747E
-_08097456:
-	ldr r0, _08097488 @ =Task_80A244C
-	bl FuncIsActiveTask
-	lsls r0, 24
-	cmp r0, 0
-	bne _08097468
-	movs r0, 0x32
-	bl sub_80974F8
-_08097468:
-	bl sub_8097540
-	lsls r0, 24
-	lsrs r0, 24
-	mov r1, sp
-	ldrb r1, [r1]
-	adds r2, r4, 0
-	bl sub_8097554
-	lsls r0, 24
-	lsrs r0, 24
-_0809747E:
-	add sp, 0x4
-	pop {r4}
-	pop {r1}
-	bx r1
-	.align 2, 0
-_08097488: .4byte Task_80A244C
-	thumb_func_end ScriptMovement_StartObjectMovementScript
-
-	thumb_func_start ScriptMovement_IsObjectMovementFinished
-ScriptMovement_IsObjectMovementFinished: @ 809748C
-	push {r4,lr}
-	sub sp, 0x4
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, 24
-	lsrs r1, 24
-	lsls r2, 24
-	lsrs r2, 24
-	mov r3, sp
-	bl TryGetObjectEventIdByLocalIdAndMap
-	lsls r0, 24
-	cmp r0, 0
-	bne _080974CE
-	bl sub_8097540
-	lsls r0, 24
-	lsrs r4, r0, 24
-	mov r0, sp
-	ldrb r1, [r0]
-	adds r0, r4, 0
-	bl sub_80975C0
-	lsls r0, 24
-	lsrs r1, r0, 24
-	cmp r1, 0x10
-	beq _080974CE
-	adds r0, r4, 0
-	bl sub_80976D0
-	lsls r0, 24
-	lsrs r0, 24
-	b _080974D0
-_080974CE:
-	movs r0, 0x1
-_080974D0:
-	add sp, 0x4
-	pop {r4}
-	pop {r1}
-	bx r1
-	thumb_func_end ScriptMovement_IsObjectMovementFinished
-
-	thumb_func_start sub_80974D8
-sub_80974D8: @ 80974D8
-	push {r4,lr}
-	bl sub_8097540
-	lsls r0, 24
-	lsrs r4, r0, 24
-	cmp r4, 0xFF
-	beq _080974F2
-	adds r0, r4, 0
-	bl UnfreezeObjects
-	adds r0, r4, 0
-	bl DestroyTask
-_080974F2:
-	pop {r4}
-	pop {r0}
-	bx r0
-	thumb_func_end sub_80974D8
-
-	thumb_func_start sub_80974F8
-sub_80974F8: @ 80974F8
-	push {r4,r5,lr}
-	adds r1, r0, 0
-	lsls r1, 24
-	lsrs r1, 24
-	ldr r0, _08097534 @ =Task_80A244C
-	bl CreateTask
-	lsls r0, 24
-	lsrs r0, 24
-	movs r2, 0x1
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r3, r1, 3
-	ldr r5, _08097538 @ =gTasks+0x8
-	ldr r0, _0809753C @ =0x0000ffff
-	adds r4, r0, 0
-_08097518:
-	lsls r0, r2, 1
-	adds r0, r3
-	adds r0, r5
-	ldrh r1, [r0]
-	orrs r1, r4
-	strh r1, [r0]
-	adds r0, r2, 0x1
-	lsls r0, 24
-	lsrs r2, r0, 24
-	cmp r2, 0xF
-	bls _08097518
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_08097534: .4byte Task_80A244C
-_08097538: .4byte gTasks+0x8
-_0809753C: .4byte 0x0000ffff
-	thumb_func_end sub_80974F8
-
-	thumb_func_start sub_8097540
-sub_8097540: @ 8097540
-	push {lr}
-	ldr r0, _08097550 @ =Task_80A244C
-	bl FindTaskIdByFunc
-	lsls r0, 24
-	lsrs r0, 24
-	pop {r1}
-	bx r1
-	.align 2, 0
-_08097550: .4byte Task_80A244C
-	thumb_func_end sub_8097540
-
-	thumb_func_start sub_8097554
-sub_8097554: @ 8097554
-	push {r4-r7,lr}
-	mov r7, r9
-	mov r6, r8
-	push {r6,r7}
-	mov r9, r2
-	lsls r0, 24
-	lsrs r5, r0, 24
-	adds r7, r5, 0
-	lsls r1, 24
-	lsrs r6, r1, 24
-	mov r8, r6
-	adds r0, r5, 0
-	adds r1, r6, 0
-	bl sub_80975C0
-	lsls r0, 24
-	lsrs r4, r0, 24
-	cmp r4, 0x10
-	beq _08097590
-	adds r0, r5, 0
-	adds r1, r4, 0
-	bl sub_80976D0
-	lsls r0, 24
-	cmp r0, 0
-	beq _080975B0
-	adds r0, r5, 0
-	adds r1, r4, 0
-	adds r2, r6, 0
-	b _080975A6
-_08097590:
-	adds r0, r7, 0
-	movs r1, 0xFF
-	bl sub_80975C0
-	lsls r0, 24
-	lsrs r4, r0, 24
-	cmp r4, 0x10
-	beq _080975B0
-	adds r0, r7, 0
-	adds r1, r4, 0
-	mov r2, r8
-_080975A6:
-	mov r3, r9
-	bl sub_8097728
-	movs r0, 0
-	b _080975B2
-_080975B0:
-	movs r0, 0x1
-_080975B2:
-	pop {r3,r4}
-	mov r8, r3
-	mov r9, r4
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	thumb_func_end sub_8097554
-
-	thumb_func_start sub_80975C0
-sub_80975C0: @ 80975C0
-	push {lr}
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, 24
-	lsrs r3, r1, 24
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	ldr r0, _080975E4 @ =gTasks+0x8
-	adds r1, r0
-	adds r1, 0x2
-	movs r2, 0
-_080975D8:
-	ldrb r0, [r1]
-	cmp r0, r3
-	bne _080975E8
-	adds r0, r2, 0
-	b _080975F6
-	.align 2, 0
-_080975E4: .4byte gTasks+0x8
-_080975E8:
-	adds r0, r2, 0x1
-	lsls r0, 24
-	lsrs r2, r0, 24
-	adds r1, 0x1
-	cmp r2, 0xF
-	bls _080975D8
-	movs r0, 0x10
-_080975F6:
-	pop {r1}
-	bx r1
-	thumb_func_end sub_80975C0
-
-	thumb_func_start sub_80975FC
-sub_80975FC: @ 80975FC
-	push {lr}
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, 24
-	lsrs r3, r1, 24
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	ldr r0, _0809762C @ =gTasks+0x8
-	adds r1, r0
-	adds r1, 0x2
-	str r1, [r2]
-	movs r0, 0
-	cmp r0, r3
-	bcs _08097628
-_0809761A:
-	adds r0, 0x1
-	lsls r0, 24
-	lsrs r0, 24
-	adds r1, 0x1
-	cmp r0, r3
-	bcc _0809761A
-	str r1, [r2]
-_08097628:
-	pop {r0}
-	bx r0
-	.align 2, 0
-_0809762C: .4byte gTasks+0x8
-	thumb_func_end sub_80975FC
-
-	thumb_func_start sub_8097630
-sub_8097630: @ 8097630
-	push {r4,lr}
-	sub sp, 0x4
-	adds r4, r2, 0
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, 24
-	lsrs r1, 24
-	lsls r4, 24
-	lsrs r4, 24
-	mov r2, sp
-	bl sub_80975FC
-	ldr r0, [sp]
-	strb r4, [r0]
-	add sp, 0x4
-	pop {r4}
-	pop {r0}
-	bx r0
-	thumb_func_end sub_8097630
-
-	thumb_func_start sub_8097654
-sub_8097654: @ 8097654
-	push {r4,lr}
-	sub sp, 0x4
-	adds r4, r2, 0
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, 24
-	lsrs r1, 24
-	mov r2, sp
-	bl sub_80975FC
-	ldr r0, [sp]
-	ldrb r0, [r0]
-	strb r0, [r4]
-	add sp, 0x4
-	pop {r4}
-	pop {r0}
-	bx r0
-	thumb_func_end sub_8097654
-
-	thumb_func_start sub_8097678
-sub_8097678: @ 8097678
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, 24
-	ldr r2, _080976A0 @ =gBitTable
-	lsrs r1, 22
-	adds r1, r2
-	ldr r2, [r1]
-	mvns r2, r2
-	lsls r2, 16
-	lsrs r2, 16
-	ldr r3, _080976A4 @ =gTasks
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	adds r1, r3
-	ldrh r0, [r1, 0x8]
-	ands r2, r0
-	strh r2, [r1, 0x8]
-	bx lr
-	.align 2, 0
-_080976A0: .4byte gBitTable
-_080976A4: .4byte gTasks
-	thumb_func_end sub_8097678
-
-	thumb_func_start sub_80976A8
-sub_80976A8: @ 80976A8
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, 24
-	ldr r3, _080976C8 @ =gTasks
-	lsls r2, r0, 2
-	adds r2, r0
-	lsls r2, 3
-	adds r2, r3
-	ldr r0, _080976CC @ =gBitTable
-	lsrs r1, 22
-	adds r1, r0
-	ldr r0, [r1]
-	ldrh r1, [r2, 0x8]
-	orrs r0, r1
-	strh r0, [r2, 0x8]
-	bx lr
-	.align 2, 0
-_080976C8: .4byte gTasks
-_080976CC: .4byte gBitTable
-	thumb_func_end sub_80976A8
-
-	thumb_func_start sub_80976D0
-sub_80976D0: @ 80976D0
-	push {lr}
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, 24
-	ldr r3, _080976F8 @ =gTasks
-	lsls r2, r0, 2
-	adds r2, r0
-	lsls r2, 3
-	adds r2, r3
-	ldr r0, _080976FC @ =gBitTable
-	lsrs r1, 22
-	adds r1, r0
-	ldr r0, [r1]
-	ldrh r1, [r2, 0x8]
-	ands r0, r1
-	cmp r0, 0
-	bne _08097700
-	movs r0, 0
-	b _08097702
-	.align 2, 0
-_080976F8: .4byte gTasks
-_080976FC: .4byte gBitTable
-_08097700:
-	movs r0, 0x1
-_08097702:
-	pop {r1}
-	bx r1
-	thumb_func_end sub_80976D0
-
-	thumb_func_start npc_obj_offscreen_culling_and_flag_update
-npc_obj_offscreen_culling_and_flag_update: @ 8097708
-	lsls r0, 24
-	ldr r2, _08097714 @ =gUnknown_2039830
-	lsrs r0, 22
-	adds r0, r2
-	str r1, [r0]
-	bx lr
-	.align 2, 0
-_08097714: .4byte gUnknown_2039830
-	thumb_func_end npc_obj_offscreen_culling_and_flag_update
-
-	thumb_func_start sub_8097718
-sub_8097718: @ 8097718
-	lsls r0, 24
-	ldr r1, _08097724 @ =gUnknown_2039830
-	lsrs r0, 22
-	adds r0, r1
-	ldr r0, [r0]
-	bx lr
-	.align 2, 0
-_08097724: .4byte gUnknown_2039830
-	thumb_func_end sub_8097718
-
-	thumb_func_start sub_8097728
-sub_8097728: @ 8097728
-	push {r4-r6,lr}
-	mov r6, r8
-	push {r6}
-	adds r5, r0, 0
-	adds r4, r1, 0
-	adds r6, r2, 0
-	mov r8, r3
-	lsls r5, 24
-	lsrs r5, 24
-	lsls r4, 24
-	lsrs r4, 24
-	lsls r6, 24
-	lsrs r6, 24
-	adds r0, r5, 0
-	adds r1, r4, 0
-	bl sub_8097678
-	adds r0, r4, 0
-	mov r1, r8
-	bl npc_obj_offscreen_culling_and_flag_update
-	adds r0, r5, 0
-	adds r1, r4, 0
-	adds r2, r6, 0
-	bl sub_8097630
-	pop {r3}
-	mov r8, r3
-	pop {r4-r6}
-	pop {r0}
-	bx r0
-	thumb_func_end sub_8097728
-
-	thumb_func_start UnfreezeObjects
-UnfreezeObjects: @ 8097768
-	push {r4,r5,lr}
-	lsls r0, 24
-	lsrs r0, 24
-	lsls r1, r0, 2
-	adds r1, r0
-	lsls r1, 3
-	ldr r0, _080977A4 @ =gTasks+0x8
-	adds r1, r0
-	adds r4, r1, 0x2
-	movs r5, 0
-_0809777C:
-	ldrb r0, [r4]
-	cmp r0, 0xFF
-	beq _08097792
-	adds r1, r0, 0
-	lsls r0, r1, 3
-	adds r0, r1
-	lsls r0, 2
-	ldr r1, _080977A8 @ =gObjectEvents
-	adds r0, r1
-	bl UnfreezeObjectEvent
-_08097792:
-	adds r0, r5, 0x1
-	lsls r0, 24
-	lsrs r5, r0, 24
-	adds r4, 0x1
-	cmp r5, 0xF
-	bls _0809777C
-	pop {r4,r5}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_080977A4: .4byte gTasks+0x8
-_080977A8: .4byte gObjectEvents
-	thumb_func_end UnfreezeObjects
-
-	thumb_func_start Task_80A244C
-Task_80A244C: @ 80977AC
-	push {r4-r7,lr}
-	sub sp, 0x4
-	lsls r0, 24
-	lsrs r7, r0, 24
-	movs r5, 0
-	mov r6, sp
-_080977B8:
-	adds r0, r7, 0
-	adds r1, r5, 0
-	mov r2, sp
-	bl sub_8097654
-	ldrb r0, [r6]
-	cmp r0, 0xFF
-	beq _080977DC
-	adds r4, r0, 0
-	adds r0, r5, 0
-	bl sub_8097718
-	adds r3, r0, 0
-	adds r0, r7, 0
-	adds r1, r5, 0
-	adds r2, r4, 0
-	bl sub_80977F0
-_080977DC:
-	adds r0, r5, 0x1
-	lsls r0, 24
-	lsrs r5, r0, 24
-	cmp r5, 0xF
-	bls _080977B8
-	add sp, 0x4
-	pop {r4-r7}
-	pop {r0}
-	bx r0
-	thumb_func_end Task_80A244C
-
-	thumb_func_start sub_80977F0
-sub_80977F0: @ 80977F0
-	push {r4-r7,lr}
-	mov r7, r8
-	push {r7}
-	adds r6, r3, 0
-	lsls r0, 24
-	lsrs r0, 24
-	adds r7, r0, 0
-	lsls r1, 24
-	lsrs r5, r1, 24
-	mov r8, r5
-	lsls r2, 24
-	lsrs r4, r2, 24
-	adds r1, r5, 0
-	bl sub_80976D0
-	lsls r0, 24
-	lsrs r0, 24
-	cmp r0, 0x1
-	beq _0809786A
-	lsls r0, r4, 3
-	adds r0, r4
-	lsls r0, 2
-	ldr r1, _08097850 @ =gObjectEvents
-	adds r4, r0, r1
-	adds r0, r4, 0
-	bl ObjectEventIsSpecialAnimActive
-	lsls r0, 24
-	cmp r0, 0
-	beq _08097838
-	adds r0, r4, 0
-	bl ObjectEventClearHeldMovementIfFinished
-	lsls r0, 24
-	cmp r0, 0
-	beq _0809786A
-_08097838:
-	ldrb r1, [r6]
-	cmp r1, 0xFE
-	bne _08097854
-	adds r0, r7, 0
-	adds r1, r5, 0
-	bl sub_80976A8
-	adds r0, r4, 0
-	bl FreezeObjectEvent
-	b _0809786A
-	.align 2, 0
-_08097850: .4byte gObjectEvents
-_08097854:
-	adds r0, r4, 0
-	bl ObjectEventSetHeldMovement
-	lsls r0, 24
-	cmp r0, 0
-	bne _0809786A
-	adds r6, 0x1
-	mov r0, r8
-	adds r1, r6, 0
-	bl npc_obj_offscreen_culling_and_flag_update
-_0809786A:
-	pop {r3}
-	mov r8, r3
-	pop {r4-r7}
-	pop {r0}
-	bx r0
-	thumb_func_end sub_80977F0
-
-	.align 2, 0 @ Don't pad with nop.
diff --git a/include/script_movement.h b/include/script_movement.h
index 2a6dbd2a7..a6f3e7c3c 100644
--- a/include/script_movement.h
+++ b/include/script_movement.h
@@ -5,6 +5,6 @@
 
 bool8 ScriptMovement_StartObjectMovementScript(u8, u8, u8, const u8 *);
 bool8 ScriptMovement_IsObjectMovementFinished(u8, u8, u8);
-void sub_80974D8(void);
+void ScriptMovement_UnfreezeObjectEvents(void);
 
 #endif // GUARD_SCRIPT_MOVEMENT_H
diff --git a/include/task.h b/include/task.h
index 7a7a2ff22..0d605b04d 100644
--- a/include/task.h
+++ b/include/task.h
@@ -3,20 +3,23 @@
 
 #include "global.h"
 
+#define HEAD_SENTINEL 0xFE
+#define TAIL_SENTINEL 0xFF
+
 #define NUM_TASKS 16
-#define TASK_NONE 0xFF
+#define NUM_TASK_DATA 16
 
 typedef void (*TaskFunc)(u8 taskId);
 
 struct Task
 {
-    /*0x00*/ TaskFunc func;
-    /*0x04*/ bool8 isActive;
-    /*0x05*/ u8 prev;
-    /*0x06*/ u8 next;
-    /*0x07*/ u8 priority;
-    /*0x08*/ s16 data[16];
-}; /*size = 0x28*/
+    TaskFunc func;
+    bool8 isActive;
+    u8 prev;
+    u8 next;
+    u8 priority;
+    s16 data[NUM_TASK_DATA];
+};
 
 extern struct Task gTasks[];
 
diff --git a/ld_script.txt b/ld_script.txt
index eb6f285e5..74607f92e 100644
--- a/ld_script.txt
+++ b/ld_script.txt
@@ -130,7 +130,7 @@ SECTIONS {
         src/trainer_card.o(.text);
         asm/pokemon_storage_system.o(.text);
         src/pokemon_icon.o(.text);
-        asm/script_movement.o(.text);
+        src/script_movement.o(.text);
         asm/fldeff_cut.o(.text);
         src/mail_data.o(.text);
         src/map_name_popup.o(.text);
diff --git a/src/battle_anim_sound_tasks.c b/src/battle_anim_sound_tasks.c
index d74b743e8..f2740a1a5 100644
--- a/src/battle_anim_sound_tasks.c
+++ b/src/battle_anim_sound_tasks.c
@@ -178,7 +178,7 @@ void sub_80DD148(u8 taskId)
     gTasks[taskId].data[2] = pan;
     if (species != SPECIES_NONE)
     {
-        if (gBattleAnimArgs[1] == TASK_NONE)
+        if (gBattleAnimArgs[1] == TAIL_SENTINEL)
             PlayCry3(species, pan, 9);
         else
             PlayCry3(species, pan, 7);
@@ -199,7 +199,7 @@ static void sub_80DD270(u8 taskId)
     {
         ++gTasks[taskId].data[9];
     }
-    else if (gTasks[taskId].data[0] == TASK_NONE)
+    else if (gTasks[taskId].data[0] == TAIL_SENTINEL)
     {
         if (!IsCryPlaying())
         {
diff --git a/src/battle_transition.c b/src/battle_transition.c
index 463a3d930..b33d72f15 100644
--- a/src/battle_transition.c
+++ b/src/battle_transition.c
@@ -644,7 +644,7 @@ static bool8 BT_Phase1Blink(struct Task *task)
 
 static bool8 BT_WaitForPhase1(struct Task *task)
 {
-    if (FindTaskIdByFunc(sBT_Phase1Tasks[task->tTransitionId]) == TASK_NONE)
+    if (FindTaskIdByFunc(sBT_Phase1Tasks[task->tTransitionId]) == TAIL_SENTINEL)
     {
         ++task->tState;
         return TRUE;
@@ -665,7 +665,7 @@ static bool8 BT_Phase2LaunchAnimTask(struct Task *task)
 static bool8 BT_WaitForPhase2(struct Task *task)
 {
     task->tTransitionDone = FALSE;
-    if (FindTaskIdByFunc(sBT_Phase2Tasks[task->tTransitionId]) == TASK_NONE)
+    if (FindTaskIdByFunc(sBT_Phase2Tasks[task->tTransitionId]) == TAIL_SENTINEL)
         task->tTransitionDone = TRUE;
     return FALSE;
 }
@@ -3432,7 +3432,7 @@ static void BT_CreatePhase1SubTask(s16 fadeOutDelay, s16 fadeInDelay, s16 blinkT
 
 static bool8 BT_IsPhase1Done(void)
 {
-    if (FindTaskIdByFunc(BT_Phase1SubTask) == TASK_NONE)
+    if (FindTaskIdByFunc(BT_Phase1SubTask) == TAIL_SENTINEL)
         return TRUE;
     else
         return FALSE;
diff --git a/src/event_object_lock.c b/src/event_object_lock.c
index 2bb9736aa..02f0557f2 100644
--- a/src/event_object_lock.c
+++ b/src/event_object_lock.c
@@ -87,7 +87,7 @@ void sub_80696C0(void)
 {
     u8 objectEventId = GetObjectEventIdByLocalIdAndMap(0xFF, 0, 0);
     ObjectEventClearHeldMovementIfFinished(&gObjectEvents[objectEventId]);
-    sub_80974D8();
+    ScriptMovement_UnfreezeObjectEvents();
     UnfreezeObjectEvents();
 }
 
@@ -98,7 +98,7 @@ void UnionRoom_UnlockPlayerAndChatPartner(void)
         ObjectEventClearHeldMovementIfFinished(&gObjectEvents[gSelectedObjectEvent]);
     objectEventId = GetObjectEventIdByLocalIdAndMap(0xFF, 0, 0);
     ObjectEventClearHeldMovementIfFinished(&gObjectEvents[objectEventId]);
-    sub_80974D8();
+    ScriptMovement_UnfreezeObjectEvents();
     UnfreezeObjectEvents();
 }
 
diff --git a/src/list_menu.c b/src/list_menu.c
index bd1d2699e..21ef40fbe 100644
--- a/src/list_menu.c
+++ b/src/list_menu.c
@@ -256,7 +256,7 @@ void DestroyListMenuTask(u8 listTaskId, u16 *cursorPos, u16 *itemsAbove)
     if (itemsAbove != NULL)
         *itemsAbove = list->itemsAbove;
 
-    if (list->taskId != TASK_NONE)
+    if (list->taskId != TAIL_SENTINEL)
         ListMenuRemoveCursorObject(list->taskId, list->template.cursorKind - 2);
 
     DestroyTask(listTaskId);
@@ -346,7 +346,7 @@ static u8 ListMenuInitInternal(const struct ListMenuTemplate *listMenuTemplate,
     list->itemsAbove = itemsAbove;
     list->unk_1C = 0;
     list->unk_1D = 0;
-    list->taskId = TASK_NONE;
+    list->taskId = TAIL_SENTINEL;
     list->unk_1F = 0;
     gListMenuOverride.cursorPal = list->template.cursorPal;
     gListMenuOverride.fillValue = list->template.fillValue;
@@ -418,12 +418,12 @@ static void ListMenuDrawCursor(struct ListMenu *list)
     case 1:
         break;
     case 2:
-        if (list->taskId == TASK_NONE)
+        if (list->taskId == TAIL_SENTINEL)
             list->taskId = ListMenuAddCursorObject(list, 0);
         ListMenuUpdateCursorObject(list->taskId, GetWindowAttribute(list->template.windowId, WINDOW_TILEMAP_LEFT) * 8 - 1, GetWindowAttribute(list->template.windowId, WINDOW_TILEMAP_TOP) * 8 + y - 1, 0);
         break;
     case 3:
-        if (list->taskId == TASK_NONE)
+        if (list->taskId == TAIL_SENTINEL)
             list->taskId = ListMenuAddCursorObject(list, 1);
         ListMenuUpdateCursorObject(list->taskId, GetWindowAttribute(list->template.windowId, WINDOW_TILEMAP_LEFT) * 8 + x, GetWindowAttribute(list->template.windowId, WINDOW_TILEMAP_TOP) * 8 + y, 1);
         break;
diff --git a/src/palette.c b/src/palette.c
index 6609c9baa..04638f6d1 100644
--- a/src/palette.c
+++ b/src/palette.c
@@ -948,7 +948,7 @@ void sub_8071898(void)
     while (TRUE)
     {
         taskId = FindTaskIdByFunc(sub_80718B8);
-        if (taskId == TASK_NONE)
+        if (taskId == TAIL_SENTINEL)
             break;
         DestroyTask(taskId);
     }
diff --git a/src/rock.c b/src/rock.c
index 082f3b655..3ec9cec04 100644
--- a/src/rock.c
+++ b/src/rock.c
@@ -704,7 +704,7 @@ static void sub_80B4F78(struct Sprite *sprite)
     {
         u8 taskId = FindTaskIdByFunc(sub_80B4D00);
 
-        if (taskId != TASK_NONE)
+        if (taskId != TAIL_SENTINEL)
             --gTasks[taskId].data[11];
         DestroySprite(sprite);
     }
diff --git a/src/scrcmd.c b/src/scrcmd.c
index 389bf0cc2..77b87aaa8 100644
--- a/src/scrcmd.c
+++ b/src/scrcmd.c
@@ -1238,7 +1238,7 @@ bool8 ScrCmd_releaseall(struct ScriptContext *ctx)
     HideFieldMessageBox();
     playerObjectId = GetObjectEventIdByLocalIdAndMap(0xFF, 0, 0);
     ObjectEventClearHeldMovementIfFinished(&gObjectEvents[playerObjectId]);
-    sub_80974D8();
+    ScriptMovement_UnfreezeObjectEvents();
     UnfreezeObjectEvents();
     return FALSE;
 }
@@ -1252,7 +1252,7 @@ bool8 ScrCmd_release(struct ScriptContext *ctx)
         ObjectEventClearHeldMovementIfFinished(&gObjectEvents[gSelectedObjectEvent]);
     playerObjectId = GetObjectEventIdByLocalIdAndMap(0xFF, 0, 0);
     ObjectEventClearHeldMovementIfFinished(&gObjectEvents[playerObjectId]);
-    sub_80974D8();
+    ScriptMovement_UnfreezeObjectEvents();
     UnfreezeObjectEvents();
     return FALSE;
 }
diff --git a/src/script_movement.c b/src/script_movement.c
new file mode 100644
index 000000000..7503e8f44
--- /dev/null
+++ b/src/script_movement.c
@@ -0,0 +1,226 @@
+#include "global.h"
+#include "task.h"
+#include "util.h"
+#include "event_object_movement.h"
+#include "constants/event_objects.h"
+#include "constants/event_object_movement.h"
+
+static EWRAM_DATA const u8 (*sMovementScripts[OBJECT_EVENTS_COUNT]) = {};
+
+static void ScriptMovement_StartMoveObjects(u8 priority);
+static u8 GetMoveObjectsTaskId(void);
+static u8 ScriptMovement_TryAddNewMovement(u8 taskId, u8 objEventId, const u8 *movementScript);
+static u8 GetMovementScriptIdFromObjectEventId(u8 taskId, u8 objEventId);
+static bool8 IsMovementScriptFinished(u8 taskId, u8 moveScrId);
+static void ScriptMovement_MoveObjects(u8 taskId);
+static void ScriptMovement_AddNewMovement(u8 taskId, u8 moveScrId, u8 objEventId, const u8 *movementScript);
+static void ScriptMovement_UnfreezeActiveObjects(u8 taskId);
+static void ScriptMovement_TakeStep(u8 taskId, u8 moveScrId, u8 objEventId, const u8 *movementScript);
+
+bool8 ScriptMovement_StartObjectMovementScript(u8 localId, u8 mapNum, u8 mapGroup, const u8 *movementScript)
+{
+    u8 objEventId;
+    if (TryGetObjectEventIdByLocalIdAndMap(localId, mapNum, mapGroup, &objEventId))
+        return TRUE;
+
+    if (!FuncIsActiveTask(ScriptMovement_MoveObjects))
+        ScriptMovement_StartMoveObjects(50);
+    return ScriptMovement_TryAddNewMovement(GetMoveObjectsTaskId(), objEventId, movementScript);
+}
+
+bool8 ScriptMovement_IsObjectMovementFinished(u8 localId, u8 mapNum, u8 mapGroup)
+{
+    u8 objEventId;
+    u8 taskId;
+    u8 moveScrId;
+    if (TryGetObjectEventIdByLocalIdAndMap(localId, mapNum, mapGroup, &objEventId))
+        return TRUE;
+    taskId = GetMoveObjectsTaskId();
+    moveScrId = GetMovementScriptIdFromObjectEventId(taskId, objEventId);
+    if (moveScrId == OBJECT_EVENTS_COUNT)
+        return TRUE;
+    return IsMovementScriptFinished(taskId, moveScrId);
+}
+
+void ScriptMovement_UnfreezeObjectEvents(void)
+{
+    u8 taskId = GetMoveObjectsTaskId();
+    if (taskId != TAIL_SENTINEL)
+    {
+        ScriptMovement_UnfreezeActiveObjects(taskId);
+        DestroyTask(taskId);
+    }
+}
+
+void ScriptMovement_StartMoveObjects(u8 priority)
+{
+    u8 i;
+    u8 taskId = CreateTask(ScriptMovement_MoveObjects, priority);
+    for (i = 1; i < NUM_TASK_DATA; i++)
+    {
+        gTasks[taskId].data[i] = -1;
+    }
+}
+
+u8 GetMoveObjectsTaskId(void)
+{
+    return FindTaskIdByFunc(ScriptMovement_MoveObjects);
+}
+
+bool8 ScriptMovement_TryAddNewMovement(u8 taskId, u8 objEventId, const u8 *movementScript)
+{
+    u8 moveScrId;
+
+    moveScrId = GetMovementScriptIdFromObjectEventId(taskId, objEventId);
+    if (moveScrId != OBJECT_EVENTS_COUNT)
+    {
+        if (IsMovementScriptFinished(taskId, moveScrId) == FALSE)
+        {
+            return TRUE;
+        }
+        else
+        {
+            ScriptMovement_AddNewMovement(taskId, moveScrId, objEventId, movementScript);
+            return FALSE;
+        }
+    }
+    moveScrId = GetMovementScriptIdFromObjectEventId(taskId, OBJ_EVENT_ID_PLAYER);
+    if (moveScrId == OBJECT_EVENTS_COUNT)
+    {
+        return TRUE;
+    }
+    else
+    {
+        ScriptMovement_AddNewMovement(taskId, moveScrId, objEventId, movementScript);
+        return FALSE;
+    }
+}
+
+u8 GetMovementScriptIdFromObjectEventId(u8 taskId, u8 objEventId)
+{
+    u8 i;
+    u8 *moveScriptId = (u8 *)&gTasks[taskId].data[1];
+    for (i = 0; i < OBJECT_EVENTS_COUNT; i++, moveScriptId++)
+    {
+        if (*moveScriptId == objEventId)
+            return i;
+    }
+    return OBJECT_EVENTS_COUNT;
+}
+
+void LoadObjectEventIdPtrFromMovementScript(u8 taskId, u8 moveScrId, u8 **pObjEventId)
+{
+    u8 i;
+
+    *pObjEventId = (u8 *)&gTasks[taskId].data[1];
+    for (i = 0; i < moveScrId; i++, (*pObjEventId)++)
+        ;
+}
+
+void SetObjectEventIdAtMovementScript(u8 taskId, u8 moveScrId, u8 objEventId)
+{
+    u8 *ptr;
+
+    LoadObjectEventIdPtrFromMovementScript(taskId, moveScrId, &ptr);
+    *ptr = objEventId;
+}
+
+void LoadObjectEventIdFromMovementScript(u8 taskId, u8 moveScrId, u8 *objEventId)
+{
+    u8 *ptr;
+
+    LoadObjectEventIdPtrFromMovementScript(taskId, moveScrId, &ptr);
+    *objEventId = *ptr;
+}
+
+
+static void ClearMovementScriptFinished(u8 taskId, u8 moveScrId)
+{
+    u16 mask = ~gBitTable[moveScrId];
+
+    gTasks[taskId].data[0] &= mask;
+}
+
+static void SetMovementScriptFinished(u8 taskId, u8 moveScrId)
+{
+    gTasks[taskId].data[0] |= gBitTable[moveScrId];
+}
+
+static bool8 IsMovementScriptFinished(u8 taskId, u8 moveScrId)
+{
+    u16 moveScriptFinished = (u16)gTasks[taskId].data[0] & gBitTable[moveScrId];
+
+    if (moveScriptFinished != 0)
+        return TRUE;
+    else
+        return FALSE;
+}
+
+static void SetMovementScript(u8 moveScrId, const u8 *movementScript)
+{
+    sMovementScripts[moveScrId] = movementScript;
+}
+
+static const u8 *GetMovementScript(u8 moveScrId)
+{
+    return sMovementScripts[moveScrId];
+}
+
+static void ScriptMovement_AddNewMovement(u8 taskId, u8 moveScrId, u8 objEventId, const u8 *movementScript)
+{
+    ClearMovementScriptFinished(taskId, moveScrId);
+    SetMovementScript(moveScrId, movementScript);
+    SetObjectEventIdAtMovementScript(taskId, moveScrId, objEventId);
+}
+
+static void ScriptMovement_UnfreezeActiveObjects(u8 taskId)
+{
+    u8 *pObjEventId;
+    u8 i;
+
+    pObjEventId = (u8 *)&gTasks[taskId].data[1];
+    for (i = 0; i < OBJECT_EVENTS_COUNT; i++, pObjEventId++)
+    {
+        if (*pObjEventId != 0xFF)
+            UnfreezeObjectEvent(&gObjectEvents[*pObjEventId]);
+    }
+}
+
+static void ScriptMovement_MoveObjects(u8 taskId)
+{
+    u8 i;
+    u8 objEventId;
+
+    for (i = 0; i < OBJECT_EVENTS_COUNT; i++)
+    {
+        LoadObjectEventIdFromMovementScript(taskId, i, &objEventId);
+        if (objEventId != 0xFF)
+            ScriptMovement_TakeStep(taskId, i, objEventId, GetMovementScript(i));
+    }
+}
+
+static void ScriptMovement_TakeStep(u8 taskId, u8 moveScrId, u8 objEventId, const u8 *movementScript)
+{
+    u8 nextMoveActionId;
+
+    if (IsMovementScriptFinished(taskId, moveScrId) == TRUE)
+        return;
+    if (ObjectEventIsSpecialAnimActive(&gObjectEvents[objEventId])
+        && !ObjectEventClearHeldMovementIfFinished(&gObjectEvents[objEventId]))
+        return;
+
+    nextMoveActionId = *movementScript;
+    if (nextMoveActionId == MOVEMENT_ACTION_STEP_END)
+    {
+        SetMovementScriptFinished(taskId, moveScrId);
+        FreezeObjectEvent(&gObjectEvents[objEventId]);
+    }
+    else
+    {
+        if (!ObjectEventSetHeldMovement(&gObjectEvents[objEventId], nextMoveActionId))
+        {
+            movementScript++;
+            SetMovementScript(moveScrId, movementScript);
+        }
+    }
+}
diff --git a/sym_ewram.txt b/sym_ewram.txt
index 877a870c5..d358929eb 100644
--- a/sym_ewram.txt
+++ b/sym_ewram.txt
@@ -216,9 +216,10 @@ gUnknown_2039828: @ 2039828
 gUnknown_203982C: @ 203982C
 	.space 0x4
 
-gUnknown_2039830: @ 2039830
-	.space 0x40
+	.align 2
+	.include "src/script_movement.o"
 
+	.align 2
 gUnknown_2039870: @ 2039870
 	.space 0x4