Modified VU0MixVec. Corrected clobbers.

For readability the operands have also been changed to symbolic
names. The noinline attribute is required for functionality on
the new toolchain. It should have virtually no effect on the old
toolchain.

src/gui.c

@@ -994,30 +994,29 @@ static float fade(float t)
 // The same as mix, but with 8 (2*4) values mixed at once
 static void VU0MixVec(VU_VECTOR *a, VU_VECTOR *b, float mix, VU_VECTOR *res)
 {
-    asm(
+    asm volatile(
 #if __GNUC__ > 3
-        "lqc2   $vf1, 0(%0)\n"          // load the first vector
-        "lqc2   $vf2, 0(%1)\n"          // load the second vector
-        "lw $2, 0(%2)\n"               // load value from ptr to reg
-        "qmtc2  $2, $vf3\n"             // load the mix value from reg to VU
-        "vaddw.x $vf5, $vf0, $vf0\n"    // vf5.x = 1
-        "vsub.x $vf4x, $vf5x, $vf3x\n"    // subtract 1 - vf3,x, store the result in vf4.x
+        "lqc2   $vf1, (%[a])\n"           // load the first vector
+        "lqc2   $vf2, (%[b])\n"           // load the second vector
+        "qmtc2  %[mix], $vf3\n"           // move the mix value from reg to VU
+        "vaddw.x $vf5, $vf0, $vf0\n"      // vf5.x = 1
+        "vsub.x  $vf4x, $vf5x, $vf3x\n"   // subtract 1 - vf3,x, store the result in vf4.x
         "vmulax.xyzw $ACC, $vf1, $vf3x\n" // multiply vf1 by vf3.x, store the result in ACC
         "vmaddx.xyzw $vf1, $vf2, $vf4x\n" // multiply vf2 by vf4.x add ACC, store the result in vf1
-        "sqc2   $vf1, 0(%3)\n"          // transfer the result in acc to the ee
+        "sqc2   $vf1, (%[res])\n"         // transfer the result in acc to the ee
 #else
-        "lqc2	vf1, 0(%0)\n"          // load the first vector
-        "lqc2	vf2, 0(%1)\n"          // load the second vector
-        "lw	$2, 0(%2)\n"               // load value from ptr to reg
-        "qmtc2	$2, vf3\n"             // load the mix value from reg to VU
+        "lqc2	vf1, (%[a])\n"         // load the first vector
+        "lqc2	vf2, (%[b])\n"         // load the second vector
+        "qmtc2	%[mix], vf3\n"         // move the mix value from reg to VU
         "vaddw.x vf5, vf00, vf00\n"    // vf5.x = 1
         "vsub.x vf4x, vf5x, vf3x\n"    // subtract 1 - vf3,x, store the result in vf4.x
         "vmulax.xyzw ACC, vf1, vf3x\n" // multiply vf1 by vf3.x, store the result in ACC
         "vmaddx.xyzw vf1, vf2, vf4x\n" // multiply vf2 by vf4.x add ACC, store the result in vf1
-        "sqc2	vf1, 0(%3)\n"          // transfer the result in acc to the ee
+        "sqc2	vf1, (%[res])\n"       // transfer the result in acc to the ee
 #endif
-        :
-        : "r"(a), "r"(b), "r"(&mix), "r"(res));
+        : [res] "+r"(res)
+        : [a] "r"(a), [b] "r"(b), [mix] "r"(mix)
+        : "memory");
 }
 
 static float guiCalcPerlin(float x, float y, float z)