diff --git a/include/gba/io_reg.h b/include/gba/io_reg.h
index 1daa99e1d..148ce31db 100644
--- a/include/gba/io_reg.h
+++ b/include/gba/io_reg.h
@@ -482,6 +482,7 @@
 #define REG_SIODATA32   (*(vu32 *)REG_ADDR_SIODATA32)
 #define REG_SIOMLT_SEND (*(vu16 *)REG_ADDR_SIOMLT_SEND)
 #define REG_SIOMLT_RECV (*(vu64 *)REG_ADDR_SIOMLT_RECV)
+#define REG_SIOMULTI(n) (*(vu16 *)(REG_ADDR_SIOMULTI0 + (n) * 2))
 #define REG_SIOMULTI0   (*(vu16 *)REG_ADDR_SIOMULTI0)
 #define REG_SIOMULTI1   (*(vu16 *)REG_ADDR_SIOMULTI1)
 #define REG_SIOMULTI2   (*(vu16 *)REG_ADDR_SIOMULTI2)
diff --git a/src/battle_anim_effects_2.c b/src/battle_anim_effects_2.c
index 27149873d..5944bc511 100755
--- a/src/battle_anim_effects_2.c
+++ b/src/battle_anim_effects_2.c
@@ -2394,12 +2394,12 @@ void AnimTask_SketchDrawMon(u8 taskId)
     if (GetBattlerSpriteBGPriorityRank(gBattleAnimTarget) == 1)
     {
         task->data[6] = gBattle_BG1_X;
-        params.dmaDest = (u16 *)REG_ADDR_BG1HOFS;
+        params.dmaDest = &REG_BG1HOFS;
     }
     else
     {
         task->data[6] = gBattle_BG2_X;
-        params.dmaDest = (u16 *)REG_ADDR_BG2HOFS;
+        params.dmaDest = &REG_BG2HOFS;
     }
 
     for (i = task->data[0] - 0x40; i <= task->data[0]; i++)
diff --git a/src/battle_anim_ghost.c b/src/battle_anim_ghost.c
index 03a003c60..60e943adf 100644
--- a/src/battle_anim_ghost.c
+++ b/src/battle_anim_ghost.c
@@ -653,9 +653,9 @@ static void AnimTask_SpiteTargetShadow_Step1(u8 taskId)
             startLine = 0;
 
         if (position == 1)
-            task->data[10] = ScanlineEffect_InitWave(startLine, startLine + 64, 2, 6, 0, 4, 1);
+            task->data[10] = ScanlineEffect_InitWave(startLine, startLine + 64, 2, 6, 0, SCANLINE_EFFECT_REG_BG1HOFS, 1);
         else
-            task->data[10] = ScanlineEffect_InitWave(startLine, startLine + 64, 2, 6, 0, 8, 1);
+            task->data[10] = ScanlineEffect_InitWave(startLine, startLine + 64, 2, 6, 0, SCANLINE_EFFECT_REG_BG2HOFS, 1);
 
         task->data[15]++;
         break;
diff --git a/src/battle_anim_water.c b/src/battle_anim_water.c
index 50918a24e..44df78421 100644
--- a/src/battle_anim_water.c
+++ b/src/battle_anim_water.c
@@ -960,7 +960,7 @@ static void AnimTask_SurfWaveScanlineEffect(u8 taskId)
         else
             gScanlineEffectRegBuffers[0][i] = gScanlineEffectRegBuffers[1][i] = task->data[2];
 
-        params.dmaDest = (vu16 *)REG_ADDR_BLDALPHA;
+        params.dmaDest = &REG_BLDALPHA;
         params.dmaControl = SCANLINE_EFFECT_DMACNT_16BIT;
         params.initState = 1;
         params.unused9 = 0;
diff --git a/src/battle_dome.c b/src/battle_dome.c
index 45df83c7c..1b067924f 100644
--- a/src/battle_dome.c
+++ b/src/battle_dome.c
@@ -870,7 +870,7 @@ static const struct WindowTemplate sInfoCardWindowTemplates[] =
 
 static const struct ScanlineEffectParams sTourneyTreeScanlineEffectParams =
 {
-    .dmaDest = (void *)REG_ADDR_BG3CNT,
+    .dmaDest = &REG_BG3CNT,
     .dmaControl = SCANLINE_EFFECT_DMACNT_16BIT,
     .initState = 1,
 };
diff --git a/src/battle_main.c b/src/battle_main.c
index 8079546d4..85e1e1796 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -249,13 +249,13 @@ u8 gBattleControllerData[MAX_BATTLERS_COUNT]; // Used by the battle controllers
 
 static const struct ScanlineEffectParams sIntroScanlineParams16Bit =
 {
-    (void *)REG_ADDR_BG3HOFS, SCANLINE_EFFECT_DMACNT_16BIT, 1
+    &REG_BG3HOFS, SCANLINE_EFFECT_DMACNT_16BIT, 1
 };
 
 // unused
 static const struct ScanlineEffectParams sIntroScanlineParams32Bit =
 {
-    (void *)REG_ADDR_BG3HOFS, SCANLINE_EFFECT_DMACNT_32BIT, 1
+    &REG_BG3HOFS, SCANLINE_EFFECT_DMACNT_32BIT, 1
 };
 
 const struct SpriteTemplate gUnusedBattleInitSprite =
diff --git a/src/field_screen_effect.c b/src/field_screen_effect.c
index c27ec6c4c..0cf5e4145 100644
--- a/src/field_screen_effect.c
+++ b/src/field_screen_effect.c
@@ -56,7 +56,7 @@ const s32 gMaxFlashLevel = ARRAY_COUNT(sFlashLevelPixelRadii) - 1;
 
 const struct ScanlineEffectParams sFlashEffectParams =
 {
-    (void *)REG_ADDR_WIN0H,
+    &REG_WIN0H,
     ((DMA_ENABLE | DMA_START_HBLANK | DMA_REPEAT | DMA_DEST_RELOAD) << 16) | 1,
     1
 };
diff --git a/src/intro.c b/src/intro.c
index 5cf99c97e..024706f6c 100644
--- a/src/intro.c
+++ b/src/intro.c
@@ -1848,7 +1848,7 @@ static void Task_Scene3_StartGroudon(u8 taskId)
 {
     gTasks[taskId].tState = 0;
     gTasks[taskId].func = Task_Scene3_Groudon;
-    ScanlineEffect_InitWave(0, 160, 4, 4, 1, 4, 0);
+    ScanlineEffect_InitWave(0, 160, 4, 4, 1, SCANLINE_EFFECT_REG_BG1HOFS, 0);
 }
 
 #define tScreenX data[1]
@@ -2058,7 +2058,7 @@ static void Task_Scene3_LoadKyogre(u8 taskId)
     gTasks[taskId].tDelay = 16;
     gTasks[taskId].tZoom = 256;
     PanFadeAndZoomScreen(gTasks[taskId].tScreenX, gTasks[taskId].tScreenY, gTasks[taskId].tZoom, 0);
-    ScanlineEffect_InitWave(0, 0xA0, 4, 4, 1, 6, 0);
+    ScanlineEffect_InitWave(0, 0xA0, 4, 4, 1, SCANLINE_EFFECT_REG_BG1VOFS, 0);
 }
 
 static void Task_Scene3_Kyogre(u8 taskId)
diff --git a/src/libisagbprn.c b/src/libisagbprn.c
index e0e979e95..69c6986ae 100644
--- a/src/libisagbprn.c
+++ b/src/libisagbprn.c
@@ -31,7 +31,7 @@ void AGBPrintFlush1Block(void);
 void AGBPrintInit(void)
 {
     volatile struct AGBPrintStruct *pPrint = (struct AGBPrintStruct *)AGB_PRINT_STRUCT_ADDR;
-    u16 *pWSCNT = (u16 *)REG_ADDR_WAITCNT;
+    u16 *pWSCNT = &REG_WAITCNT;
     u16 *pProtect = (u16 *)AGB_PRINT_PROTECT_ADDR;
     u16 nOldWSCNT = *pWSCNT;
     *pWSCNT = WSCNT_DATA;
@@ -57,7 +57,7 @@ static void AGBPutcInternal(const char cChr)
 
 void AGBPutc(const char cChr)
 {
-    u16 *pWSCNT = (u16 *)REG_ADDR_WAITCNT;
+    u16 *pWSCNT = &REG_WAITCNT;
     u16 nOldWSCNT = *pWSCNT;
     volatile struct AGBPrintStruct *pPrint;
     *pWSCNT = WSCNT_DATA;
@@ -71,7 +71,7 @@ void AGBPutc(const char cChr)
 void AGBPrint(const char *pBuf)
 {
     volatile struct AGBPrintStruct *pPrint = (struct AGBPrintStruct *)AGB_PRINT_STRUCT_ADDR;
-    u16 *pWSCNT = (u16 *)REG_ADDR_WAITCNT;
+    u16 *pWSCNT = &REG_WAITCNT;
     u16 nOldWSCNT = *pWSCNT;
     *pWSCNT = WSCNT_DATA;
     while (*pBuf)
@@ -105,9 +105,9 @@ static void AGBPrintTransferDataInternal(u32 bAllData)
     pProtect = (u16 *)AGB_PRINT_PROTECT_ADDR;
     pPrint = (struct AGBPrintStruct *)AGB_PRINT_STRUCT_ADDR;
     lpfnFuncFlush = (LPFN_PRINT_FLUSH)AGB_PRINT_FLUSH_ADDR;
-    pIME = (u16 *)REG_ADDR_IME;
+    pIME = &REG_IME;
     nIME = *pIME;
-    pWSCNT = (u16 *)REG_ADDR_WAITCNT;
+    pWSCNT = &REG_WAITCNT;
     nOldWSCNT = *pWSCNT;
     *pIME = nIME & ~1;
     *pWSCNT = WSCNT_DATA;
diff --git a/src/librfu_intr.c b/src/librfu_intr.c
index 19ea60b06..d902b1c45 100644
--- a/src/librfu_intr.c
+++ b/src/librfu_intr.c
@@ -336,8 +336,8 @@ static u16 handshake_wait(u16 slot)
 
 static void STWI_set_timer_in_RAM(u8 count)
 {
-    vu16* regTMCNTL = (vu16*)(REG_ADDR_TMCNT_L + gSTWIStatus->timerSelect * 4);
-    vu16* regTMCNTH = (vu16*)(REG_ADDR_TMCNT_H + gSTWIStatus->timerSelect * 4);
+    vu16* regTMCNTL = &REG_TMCNT_L(gSTWIStatus->timerSelect);
+    vu16* regTMCNTH = &REG_TMCNT_H(gSTWIStatus->timerSelect);
     REG_IME = 0;
     switch (count)
     {
diff --git a/src/multiboot.c b/src/multiboot.c
index 19245b5b3..15b062ed6 100644
--- a/src/multiboot.c
+++ b/src/multiboot.c
@@ -90,7 +90,7 @@ output_burst:
         k = 0x0e;
         for (i = MULTIBOOT_NCHILD; i != 0; i--)
         {
-            if (*(vu16 *)(REG_ADDR_SIOMULTI0 + i * 2) != 0xffff)
+            if (REG_SIOMULTI(i) != 0xffff)
             {
                 break;
             }
@@ -102,7 +102,7 @@ output_burst:
 
         for (i = MULTIBOOT_NCHILD; i != 0; i--)
         {
-            j = *(vu16 *)(REG_ADDR_SIOMULTI0 + i * 2);
+            j = REG_SIOMULTI(i);
             if (mp->client_bit & (1 << i))
             {
                 if (j != ((MULTIBOOT_CLIENT_INFO << 8) | (1 << i)))
@@ -141,7 +141,7 @@ output_burst:
         mp->probe_target_bit = 0;
         for (i = MULTIBOOT_NCHILD; i != 0; i--)
         {
-            j = *(vu16 *)(REG_ADDR_SIOMULTI0 + i * 2);
+            j = REG_SIOMULTI(i);
             if ((j >> 8) == MULTIBOOT_CLIENT_INFO)
             {
                 MultiBoot_required_data[i - 1] = j;
@@ -166,7 +166,7 @@ output_burst:
         {
             if (mp->probe_target_bit & (1 << i))
             {
-                j = *(vu16 *)(REG_ADDR_SIOMULTI0 + i * 2);
+                j = REG_SIOMULTI(i);
                 if (j != MultiBoot_required_data[i - 1])
                 {
                     mp->probe_target_bit ^= 1 << i;
@@ -179,7 +179,7 @@ output_burst:
         k = 1;
         for (i = MULTIBOOT_NCHILD; i != 0; i--)
         {
-            j = *(vu16 *)(REG_ADDR_SIOMULTI0 + i * 2);
+            j = REG_SIOMULTI(i);
             mp->client_data[i - 1] = j;
             if (mp->probe_target_bit & (1 << i))
             {
@@ -214,7 +214,7 @@ output_burst:
     case 0xd1:
         for (i = MULTIBOOT_NCHILD; i != 0; i--)
         {
-            j = *(vu16 *)(REG_ADDR_SIOMULTI0 + i * 2);
+            j = REG_SIOMULTI(i);
             if (mp->probe_target_bit & (1 << i))
             {
                 if ((j >> 8) != MULTIBOOT_CLIENT_DLREADY)
@@ -242,7 +242,7 @@ output_burst:
         {
             if (mp->probe_target_bit & (1 << i))
             {
-                j = *(vu16 *)(REG_ADDR_SIOMULTI0 + i * 2);
+                j = REG_SIOMULTI(i);
                 if ((j >> 8) != (MULTIBOOT_MASTER_START_PROBE + 1 - (mp->probe_count >> 1))
                  || ((j & 0xff) != (1 << i)))
                 {
@@ -391,7 +391,7 @@ static int MultiBootHandShake(struct MultiBootParam *mp)
     default:
         for (i = MULTIBOOT_NCHILD; i != 0; i--)
         {
-            j = *(vu16 *)(REG_ADDR_SIOMULTI0 + i * 2);
+            j = REG_SIOMULTI(i);
             if ((mp->client_bit & (1 << i))
                 && j != must_data)
             {
@@ -413,7 +413,7 @@ static int MultiBootHandShake(struct MultiBootParam *mp)
     case 0xe8:
         for (i = MULTIBOOT_NCHILD; i != 0; i--)
         {
-            j = *(vu16 *)(REG_ADDR_SIOMULTI0 + i * 2);
+            j = REG_SIOMULTI(i);
             if ((mp->client_bit & (1 << i)) && j != must_data)
             {
                 MultiBootInit(mp);
diff --git a/src/overworld.c b/src/overworld.c
index 9a5c41a7f..c9aa9ba57 100644
--- a/src/overworld.c
+++ b/src/overworld.c
@@ -313,7 +313,7 @@ static const struct BgTemplate sOverworldBgTemplates[] =
 
 static const struct ScanlineEffectParams sFlashEffectParams =
 {
-    (void *)REG_ADDR_WIN0H,
+    &REG_WIN0H,
     ((DMA_ENABLE | DMA_START_HBLANK | DMA_REPEAT | DMA_DEST_RELOAD) << 16) | 1,
     1,
     0,
diff --git a/src/rayquaza_scene.c b/src/rayquaza_scene.c
index 51498fa1d..6525daa1e 100644
--- a/src/rayquaza_scene.c
+++ b/src/rayquaza_scene.c
@@ -490,7 +490,7 @@ static const struct SpriteTemplate sSpriteTemplate_DuoFightPre_KyogreDorsalFin =
 
 static const struct ScanlineEffectParams sScanlineParams_DuoFight_Clouds =
 {
-    .dmaDest = (vu16 *)REG_ADDR_BG1HOFS,
+    .dmaDest = &REG_BG1HOFS,
     .dmaControl = SCANLINE_EFFECT_DMACNT_16BIT,
     .initState = 1
 };