diff --git a/src/BossFrog.cpp b/src/BossFrog.cpp
index 172c71c3..82541d2f 100644
--- a/src/BossFrog.cpp
+++ b/src/BossFrog.cpp
@@ -573,17 +573,9 @@ void ActBossChar_Frog(void)
 			break;
 	}
 
-	boss->ym += 0x40;
-	if (boss->ym > 0x5FF)
-		boss->ym = 0x5FF;
-
-	boss->x += boss->xm;
-	boss->y += boss->ym;
-
-	if (boss->direct == DIR_LEFT)
-		boss->rect = rcLeft[boss->ani_no];
-	else
-		boss->rect = rcRight[boss->ani_no];
+	NPC_DO_GRAVITY(boss, 0x40, 0x5FF);
+	NPC_UPDATE_POSITIONS_WITH_VELOCITIES(boss);
+	NPC_SET_RECT_FROM_LEFT_RIGHT(boss, rcLeft, rcRight);
 
 	ActBossChar02_01();
 	ActBossChar02_02();
diff --git a/src/NpChar.h b/src/NpChar.h
index 185a26b8..7fb14295 100644
--- a/src/NpChar.h
+++ b/src/NpChar.h
@@ -1,11 +1,30 @@
 #pragma once
 
+#include "CommonDefines.h"
 #include "WindowsWrapper.h"
 
 #include "Draw.h"
 
 #define NPC_MAX 0x200
 
+#define NPC_CAP_Y_VELOCITY(npc, maxYVel) \
+	if (npc->ym > (maxYVel)) \
+		npc->ym = (maxYVel)
+
+#define NPC_DO_GRAVITY(npc, ymAdd, maxYVel) \
+	npc->ym += ymAdd; \
+	NPC_CAP_Y_VELOCITY(npc, maxYVel)
+
+#define NPC_UPDATE_POSITIONS_WITH_VELOCITIES(npc) \
+	npc->x += npc->xm; \
+	npc->y = npc->ym;
+
+#define NPC_SET_RECT_FROM_LEFT_RIGHT(npc, rcLeft, rcRight) \
+	if (npc->direct == DIR_LEFT) \
+		npc->rect = rcLeft[npc->ani_no]; \
+	else \
+		npc->rect = rcRight[npc->ani_no];
+
 // Be careful when changing these: they're baked into the 'npc.tbl' file
 enum NPCFlags
 {