Implement Math.log1p using port from fdlibm.

third_party/fdlibm/fdlibm.cc

 // The following is adapted from fdlibm (http://www.netlib.org/fdlibm).
 //
 // ====================================================
 // Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 //
 // Developed at SunSoft, a Sun Microsystems, Inc. business.
 // Permission to use, copy, modify, and distribute this
 // software is freely granted, provided that this notice
 // is preserved.
 // ====================================================
@@ skipping 43 matching lines @@
     3.59207910759131235356e-03,   //          24
     1.45620945432529025516e-03,   //          25
     5.88041240820264096874e-04,   //          26
     2.46463134818469906812e-04,   //          27
     7.81794442939557092300e-05,   //          28
     7.14072491382608190305e-05,   //          29
     -1.85586374855275456654e-05,  //          30
     2.59073051863633712884e-05,   // T12      31
     7.85398163397448278999e-01,   // pio4     32
     3.06161699786838301793e-17,   // pio4lo   33
+    6.93147180369123816490e-01,   // ln2_hi   34
+    1.90821492927058770002e-10,   // ln2_lo   35
+    1.80143985094819840000e+16,   // 2^54     36
+    6.666666666666666666e-01,     // 2/3      37
+    6.666666666666735130e-01,     // LP1      38
+    3.999999999940941908e-01,     //          39
+    2.857142874366239149e-01,     //          40
+    2.222219843214978396e-01,     //          41
+    1.818357216161805012e-01,     //          42
+    1.531383769920937332e-01,     //          43
+    1.479819860511658591e-01,     // LP7      44
 };
 
 
 // Table of constants for 2/pi, 396 Hex digits (476 decimal) of 2/pi
 static const int two_over_pi[] = {
     0xA2F983, 0x6E4E44, 0x1529FC, 0x2757D1, 0xF534DD, 0xC0DB62, 0x95993C,
     0x439041, 0xFE5163, 0xABDEBB, 0xC561B7, 0x246E3A, 0x424DD2, 0xE00649,
     0x2EEA09, 0xD1921C, 0xFE1DEB, 0x1CB129, 0xA73EE8, 0x8235F5, 0x2EBB44,
     0x84E99C, 0x7026B4, 0x5F7E41, 0x3991D6, 0x398353, 0x39F49C, 0x845F8B,
     0xBDF928, 0x3B1FF8, 0x97FFDE, 0x05980F, 0xEF2F11, 0x8B5A0A, 0x6D1F6D,
@@ skipping 179 matching lines @@
   int n = __kernel_rem_pio2(tx, y, e0, nx);
   if (hx < 0) {
     y[0] = -y[0];
     y[1] = -y[1];
     return -n;
   }
   return n;
 }
 }
 }  // namespace v8::internal