[Feature]add MT2731_MP2_MR2_SVN388 baseline version

Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/bsp/lk/lib/libm/s_scalbn.c b/src/bsp/lk/lib/libm/s_scalbn.c
new file mode 100644
index 0000000..ef5a685
--- /dev/null
+++ b/src/bsp/lk/lib/libm/s_scalbn.c
@@ -0,0 +1,70 @@
+/* @(#)s_scalbn.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+/*
+ * scalbn (double x, int n)
+ * scalbn(x,n) returns x* 2**n  computed by  exponent
+ * manipulation rather than by actually performing an
+ * exponentiation or a multiplication.
+ */
+
+#include <sys/cdefs.h>
+#include <float.h>
+
+#include "math.h"
+#include "math_private.h"
+
+static const double
+two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
+twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
+huge   = 1.0e+300,
+tiny   = 1.0e-300;
+
+double
+scalbn (double x, int n)
+{
+    int32_t k,hx,lx;
+    EXTRACT_WORDS(hx,lx,x);
+    k = (hx&0x7ff00000)>>20;        /* extract exponent */
+    if (k==0) {             /* 0 or subnormal x */
+        if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
+        x *= two54;
+        GET_HIGH_WORD(hx,x);
+        k = ((hx&0x7ff00000)>>20) - 54;
+        if (n< -50000) return tiny*x;   /*underflow*/
+    }
+    if (k==0x7ff) return x+x;       /* NaN or Inf */
+    k = k+n;
+    if (k >  0x7fe) return huge*copysign(huge,x); /* overflow  */
+    if (k > 0)              /* normal result */
+        {SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20)); return x;}
+
+    if (k <= -54) {
+        if (n > 50000) {  /* in case integer overflow in n+k */
+            return huge*copysign(huge,x);   /*overflow*/
+        } else {
+            return tiny*copysign(tiny,x);   /*underflow*/
+        }
+    }
+    k += 54;                /* subnormal result */
+    SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20));
+    return x*twom54;
+}
+
+#if SUPPORT_LONG_DOUBLE
+
+#if (LDBL_MANT_DIG == 53)
+__weak_reference(scalbn, ldexpl);
+__weak_reference(scalbn, scalbnl);
+#endif
+
+#endif