update documentation files for mips64 port

COPYRIGHT

@@ -43,6 +43,7 @@ Gianluca Anzolin
 Hauke Mehrtens
 Hiltjo Posthuma
 Isaac Dunham
+Jaydeep Patil
 Jens Gustedt
 Jeremy Huntwork
 Jo-Philipp Wich
@@ -55,6 +56,7 @@ Kylie McClain
 Luca Barbato
 Luka Perkov
 M Farkas-Dyck (Strake)
+Mahesh Bodapati
 Michael Forney
 Natanael Copa
 Nicholas J. Kain
@@ -123,6 +125,9 @@ Pennington for use in the ellcc project. The original code was adapted
 by Rich Felker for build system and code conventions during upstream
 integration. It is licensed under the standard MIT terms.
 
+The mips64 port was contributed by Imagination Technologies and is
+licensed under the standard MIT terms.
+
 The powerpc port was also originally written by Richard Pennington,
 and later supplemented and integrated by John Spencer. It is licensed
 under the standard MIT terms.

INSTALL

@@ -62,6 +62,12 @@ and ABI combinations:
     * MIPS2 or later, or kernel emulation of ll/sc (standard in Linux)
       is required
 
+* MIPS64
+    * ABI is n64 (LP64)
+    * Big-endian default; little-endian variants also supported
+    * Default ABI variant uses FPU registers; alternate soft-float ABI
+      that does not use FPU registers or instructions is available
+
 * PowerPC
     * Only 32-bit is supported
     * Compiler toolchain must provide 64-bit long double, not IBM