Prepare mult_matrix function

include/PSX/GTE/gte.hpp

@@ -55,6 +55,38 @@ namespace JabyEngine {
             __asm__ volatile("ctc2 $14, $7"     :: "r"(&matrix) : "$12", "$13", "$14");
         }
 
+        /*
+            MulMatrix0
+
+            m0: first input
+            m1: second input
+            result: result of multiplication
+            returns: result
+
+            Multiplies two matrices m0 and m1.
+            The function destroys the constant rotation matrix
+        */
+        static MATRIX& mult_matrix(const MATRIX& m0, const MATRIX& m1, MATRIX& result) {
+            /*
+                Jaby: Somehow this code creates stack usage.... Investigate!!
+            */
+            set_rot_matrix(m0);
+            
+            ldclmv(m1, 0);
+            rtir();
+            stclmv(result, 0);
+            
+            ldclmv(m1, 1);
+            rtir();
+            stclmv(result, 1);
+            
+            ldclmv(m1, 2);
+            rtir();
+            stclmv(result, 2);
+
+            return result;
+        }
+
         /*
             SetGeomOffset(ofx,ofy)