GB, GBA: Prevent loading null ROMs

CHANGES

@@ -24,6 +24,7 @@ Misc:
  - VFS: Call msync when syncing mapped data
  - GBA Video, GB Video: Colors are now fully scaled
  - PSP2: Improved controller rumble
+ - GB, GBA: Prevent loading null ROMs
 
 0.5.1: (2016-10-05)
 Bugfixes:

src/gb/gb.c

@@ -81,6 +81,9 @@ static void GBInit(void* cpu, struct mCPUComponent* component) {
 }
 
 bool GBLoadROM(struct GB* gb, struct VFile* vf) {
+	if (!vf) {
+		return false;
+	}
 	GBUnloadROM(gb);
 	gb->romVf = vf;
 	gb->pristineRomSize = vf->size(vf);

src/gba/gba.c

@@ -490,6 +490,9 @@ bool GBALoadMB(struct GBA* gba, struct VFile* vf) {
 }
 
 bool GBALoadROM(struct GBA* gba, struct VFile* vf) {
+	if (!vf) {
+		return false;
+	}
 	GBAUnloadROM(gba);
 	gba->romVf = vf;
 	gba->pristineRomSize = vf->size(vf);