StdLib: Add support for AArch64

- Use some files from ARM version.
- Use NetBSD software floating point library to provide floating point
  operations not handled directly by hardware floating point enabled
  GCC compiler.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Harry Liebel <Harry.Liebel@arm.com>
Reviewed-by: Olivier Martin <Olivier.Martin@arm.com>
Reviewed-by: Daryl McDaniel <edk2-lists@mc2research.org>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18118 6f19259b-4bc3-4df7-8a09-765794883524

StdLib/LibC/LibC.inf

@@ -89,6 +89,9 @@
   Main/Arm/floatunsidf.c
   Main/Arm/flt_rounds.c
 
+[Sources.AARCH64]
+  Main/Arm/flt_rounds.c
+
 [Binaries.IA32]
   LIB|Main/Ia32/ftol2.obj|*|MSFT
 

StdLib/LibC/Softfloat/Softfloat.inf

@@ -22,7 +22,7 @@
   LIBRARY_CLASS                  = LibSoftfloat
 
 #
-#  VALID_ARCHITECTURES           = ARM
+#  VALID_ARCHITECTURES           = ARM AARCH64
 #
 
 #  Only tested with GCC
@@ -43,6 +43,15 @@
   Arm/__aeabi_dcmpun.c
   Arm/__aeabi_fcmpun.c
 
+[Sources.AARCH64]
+  bits64/softfloat.c
+  eqtf2.c
+  getf2.c
+  gttf2.c
+  letf2.c
+  lttf2.c
+  netf2.c
+
 [Sources]
   fpgetround.c
   fpsetround.c

StdLib/LibC/gdtoa/gdtoa.inf

@@ -46,6 +46,10 @@
   strtof.c
   Ipf/strtold.c
 
+[Sources.AARCH64]
+  strtof.c
+  Ipf/strtold.c
+
 [Sources]
   strtod.c      # Public interfaces
   atof.c