M src/gba/gba-video.h → src/gba/gba-video.h

@@ -141,19 +141,14 @@ DECL_BIT(GBARegisterDISPSTAT, HblankIRQ, 4);
 DECL_BIT(GBARegisterDISPSTAT, VcounterIRQ, 5);
 DECL_BITS(GBARegisterDISPSTAT, VcountSetting, 8, 8);
 
-union GBARegisterBGCNT {
-	struct {
-		unsigned priority : 2;
-		unsigned charBase : 2;
-		unsigned : 2;
-		unsigned mosaic : 1;
-		unsigned multipalette : 1;
-		unsigned screenBase : 5;
-		unsigned overflow : 1;
-		unsigned size : 2;
-	};
-	uint16_t packed;
-};
+DECL_BITFIELD(GBARegisterBGCNT, uint16_t);
+DECL_BITS(GBARegisterBGCNT, Priority, 0, 2);
+DECL_BITS(GBARegisterBGCNT, CharBase, 2, 2);
+DECL_BIT(GBARegisterBGCNT, Mosaic, 6);
+DECL_BIT(GBARegisterBGCNT, 256Color, 7);
+DECL_BITS(GBARegisterBGCNT, ScreenBase, 8, 5);
+DECL_BIT(GBARegisterBGCNT, Overflow, 13);
+DECL_BITS(GBARegisterBGCNT, Size, 14, 2);
 
 struct GBAVideoRenderer {
 	void (*init)(struct GBAVideoRenderer* renderer);

M src/gba/renderers/video-software.c → src/gba/renderers/video-software.c

@@ -532,14 +532,13 @@ }
 
 static void GBAVideoSoftwareRendererWriteBGCNT(struct GBAVideoSoftwareRenderer* renderer, struct GBAVideoSoftwareBackground* bg, uint16_t value) {
 	UNUSED(renderer);
-	union GBARegisterBGCNT reg = { .packed = value };
-	bg->priority = reg.priority;
-	bg->charBase = reg.charBase << 14;
-	bg->mosaic = reg.mosaic;
-	bg->multipalette = reg.multipalette;
-	bg->screenBase = reg.screenBase << 11;
-	bg->overflow = reg.overflow;
-	bg->size = reg.size;
+	bg->priority = GBARegisterBGCNTGetPriority(value);
+	bg->charBase = GBARegisterBGCNTGetCharBase(value) << 14;
+	bg->mosaic = GBARegisterBGCNTGetMosaic(value);
+	bg->multipalette = GBARegisterBGCNTGet256Color(value);
+	bg->screenBase = GBARegisterBGCNTGetScreenBase(value) << 11;
+	bg->overflow = GBARegisterBGCNTGetOverflow(value);
+	bg->size = GBARegisterBGCNTGetSize(value);
 }
 
 static void GBAVideoSoftwareRendererWriteBGPA(struct GBAVideoSoftwareBackground* bg, uint16_t value) {