diff --git a/constants/map_data_constants.asm b/constants/map_data_constants.asm
index 32a56518c..ac00e4260 100644
--- a/constants/map_data_constants.asm
+++ b/constants/map_data_constants.asm
@@ -2,19 +2,14 @@
 ; height of north/south connections
 DEF MAP_BORDER EQU 3
 
-; connection directions
-	const_def
-	const EAST_F
-	const WEST_F
-	const SOUTH_F
-	const NORTH_F
+; wCurMapConnections    : \1
+; connection directions : BIT_\1
+	bit_const_def
+	shift_const EAST   ; $01 (BIT_EAST  ; 0)
+	shift_const WEST   ; $02 (BIT_WEST  ; 1)
+	shift_const SOUTH  ; $04 (BIT_SOUTH ; 2)
+	shift_const NORTH  ; $08 (BIT_NORTH ; 4)
 
-; wCurMapConnections
-	const_def
-	shift_const EAST   ; 1
-	shift_const WEST   ; 2
-	shift_const SOUTH  ; 4
-	shift_const NORTH  ; 8
 
 ; wWarpEntries
 DEF MAX_WARP_EVENTS EQU 32
diff --git a/constants/sprite_data_constants.asm b/constants/sprite_data_constants.asm
index e8c028d22..95f97b771 100644
--- a/constants/sprite_data_constants.asm
+++ b/constants/sprite_data_constants.asm
@@ -14,12 +14,7 @@ DEF NPC_CHANGE_FACING EQU $E0
 
 ; player direction constants
 	bit_const_def
-	const PLAYER_DIR_BIT_RIGHT ; 0
-	const PLAYER_DIR_BIT_LEFT  ; 1
-	const PLAYER_DIR_BIT_DOWN  ; 2
-	const PLAYER_DIR_BIT_UP    ; 3
-
-DEF PLAYER_DIR_RIGHT EQU 1 << PLAYER_DIR_BIT_RIGHT
-DEF PLAYER_DIR_LEFT  EQU 1 << PLAYER_DIR_BIT_LEFT
-DEF PLAYER_DIR_DOWN  EQU 1 << PLAYER_DIR_BIT_DOWN
-DEF PLAYER_DIR_UP    EQU 1 << PLAYER_DIR_BIT_UP
+	shift_const PLAYER_DIR_RIGHT ; $01 (BIT_PLAYER_DIR_RIGHT ; 0)
+	shift_const PLAYER_DIR_LEFT  ; $02 (BIT_PLAYER_DIR_LEFT  ; 1)
+	shift_const PLAYER_DIR_DOWN  ; $04 (BIT_PLAYER_DIR_DOWN  ; 2)
+	shift_const PLAYER_DIR_UP    ; $08 (BIT_PLAYER_DIR_UP    ; 3)
diff --git a/engine/items/item_effects.asm b/engine/items/item_effects.asm
index c4ce13de6..539f878ac 100644
--- a/engine/items/item_effects.asm
+++ b/engine/items/item_effects.asm
@@ -726,13 +726,13 @@ ItemUseSurfboard:
 ; uses a simulated button press to make the player move forward
 .makePlayerMoveForward
 	ld a, [wPlayerDirection] ; direction the player is going
-	bit PLAYER_DIR_BIT_UP, a
+	bit BIT_PLAYER_DIR_UP, a
 	ld b, PAD_UP
 	jr nz, .storeSimulatedButtonPress
-	bit PLAYER_DIR_BIT_DOWN, a
+	bit BIT_PLAYER_DIR_DOWN, a
 	ld b, PAD_DOWN
 	jr nz, .storeSimulatedButtonPress
-	bit PLAYER_DIR_BIT_LEFT, a
+	bit BIT_PLAYER_DIR_LEFT, a
 	ld b, PAD_LEFT
 	jr nz, .storeSimulatedButtonPress
 	ld b, PAD_RIGHT
diff --git a/engine/overworld/movement.asm b/engine/overworld/movement.asm
index a353c4f1e..27fa1f69c 100644
--- a/engine/overworld/movement.asm
+++ b/engine/overworld/movement.asm
@@ -29,22 +29,22 @@ UpdatePlayerSprite:
 	jr nz, .moving
 	ld a, [wPlayerMovingDirection]
 ; check if down
-	bit PLAYER_DIR_BIT_DOWN, a
+	bit BIT_PLAYER_DIR_DOWN, a
 	jr z, .checkIfUp
 	xor a ; ld a, SPRITE_FACING_DOWN
 	jr .next
 .checkIfUp
-	bit PLAYER_DIR_BIT_UP, a
+	bit BIT_PLAYER_DIR_UP, a
 	jr z, .checkIfLeft
 	ld a, SPRITE_FACING_UP
 	jr .next
 .checkIfLeft
-	bit PLAYER_DIR_BIT_LEFT, a
+	bit BIT_PLAYER_DIR_LEFT, a
 	jr z, .checkIfRight
 	ld a, SPRITE_FACING_LEFT
 	jr .next
 .checkIfRight
-	bit PLAYER_DIR_BIT_RIGHT, a
+	bit BIT_PLAYER_DIR_RIGHT, a
 	jr z, .notMoving
 	ld a, SPRITE_FACING_RIGHT
 	jr .next
@@ -415,17 +415,17 @@ MakeNPCFacePlayer:
 	jr nz, NotYetMoving
 	res BIT_FACE_PLAYER, [hl]
 	ld a, [wPlayerDirection]
-	bit PLAYER_DIR_BIT_UP, a
+	bit BIT_PLAYER_DIR_UP, a
 	jr z, .notFacingDown
 	ld c, SPRITE_FACING_DOWN
 	jr .facingDirectionDetermined
 .notFacingDown
-	bit PLAYER_DIR_BIT_DOWN, a
+	bit BIT_PLAYER_DIR_DOWN, a
 	jr z, .notFacingUp
 	ld c, SPRITE_FACING_UP
 	jr .facingDirectionDetermined
 .notFacingUp
-	bit PLAYER_DIR_BIT_LEFT, a
+	bit BIT_PLAYER_DIR_LEFT, a
 	jr z, .notFacingRight
 	ld c, SPRITE_FACING_RIGHT
 	jr .facingDirectionDetermined
diff --git a/home/overworld.asm b/home/overworld.asm
index e994f6942..b462f7500 100644
--- a/home/overworld.asm
+++ b/home/overworld.asm
@@ -2047,22 +2047,22 @@ LoadMapHeader::
 	ld a, [wCurMapConnections]
 	ld b, a
 ; check north
-	bit NORTH_F, b
+	bit BIT_NORTH, b
 	jr z, .checkSouth
 	ld de, wNorthConnectionHeader
 	call CopyMapConnectionHeader
 .checkSouth
-	bit SOUTH_F, b
+	bit BIT_SOUTH, b
 	jr z, .checkWest
 	ld de, wSouthConnectionHeader
 	call CopyMapConnectionHeader
 .checkWest
-	bit WEST_F, b
+	bit BIT_WEST, b
 	jr z, .checkEast
 	ld de, wWestConnectionHeader
 	call CopyMapConnectionHeader
 .checkEast
-	bit EAST_F, b
+	bit BIT_EAST, b
 	jr z, .getObjectDataPointer
 	ld de, wEastConnectionHeader
 	call CopyMapConnectionHeader
diff --git a/macros/const.asm b/macros/const.asm
index fcec8b83d..0b4c1f124 100644
--- a/macros/const.asm
+++ b/macros/const.asm
@@ -77,8 +77,14 @@ MACRO? const_export
 ENDM
 
 MACRO? shift_const
-	DEF \1 EQU 1 << const_value
-	DEF const_value += const_inc
+	IF (const_format != $FFFFFFFF) && ((const_inc > 0 && const_value > const_limit) || (const_inc < 0 && const_value < const_limit))
+		DEF failed_const_value = 1 << const_value
+		fail "Constant value cannot be {const_size_compare} than {const_limit}. Attempted to use constant value {const_value} to define constant \1 for shifted value {failed_const_value}."
+	ELSE
+		DEF BIT_\1 EQU const_value
+		DEF \1 EQU 1 << const_value
+		DEF const_value += const_inc
+	ENDC
 ENDM
 
 MACRO? const_skip