fix: IOP gp register access on newer compiler

Now the respective functions are always exposed

iop/kernel/include/defs.h

@@ -34,50 +34,38 @@ extern "C" {
 #define KSEG1ADDR(a)	((__typeof__(a))(((u32)(a) & 0x1fffffff) | KSEG1))
 
 #if !defined(USE_GP_REGISTER)
-#if __GNUC__ > 3
-#define USE_GP_REGISTER 0
-#else
 #define USE_GP_REGISTER 1
 #endif
-#endif
-
-#if USE_GP_REGISTER
-static __inline__ void *ChangeGP(void *gp)
-{
-	void *OldGP;
-
-	__asm__ volatile(	"move %0, $gp\n"
-				"move $gp, %1"
-				: "=&r"(OldGP)
-				: "r"(gp)
-				: "gp", "memory");
-
-	return OldGP;
-}
 
 static __inline__ void SetGP(void *gp)
 {
-	__asm__ volatile(	"move $gp, %0"
-				:
-				: "r"(gp)
-				: "gp", "memory");
+	register void *gpReg __asm__("gp");
+
+	gpReg = gp;
+	__asm__ __volatile__(" " ::"r"(gpReg));
 }
 
 extern void *_gp;
-#define SetModuleGP()	ChangeGP(&_gp)
 
 static __inline__ void *GetGP(void)
 {
-	void *gp;
+	register void *gpReg __asm__("gp");
 
-	__asm__ volatile(	"move %0, $gp"
-				: "=r"(gp)
-				:
-				: "memory");
+	__asm__ __volatile__(" " : "=r"(gpReg));
+	return gpReg;
+}
+
+static __inline__ void *ChangeGP(void *gp)
+{
+	void *OldGP;
 
-	return gp;
+	OldGP = GetGP();
+	SetGP(gp);
+
+	return OldGP;
 }
-#endif
+
+#define SetModuleGP()	ChangeGP(&_gp)
 
 static inline void *iop_memcpy(void *dest, const void *src, int size)
 {