math: ARM assembly implementation for Abs
math: ARM assembly implementation for Abs

Obtained on 700MHz OMAP4460:
benchmark       old ns/op    new ns/op    delta
BenchmarkAbs           61           23  -61.63%

R=dave, remyoudompheng, mtj, rsc
CC=golang-dev
http://codereview.appspot.com/6094047

scirelli/scirelli-go,Triskite/willstone-goclone,bryanxu/go-zh,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,Triskite/willstone-goclone,mhennings/marcohennings-go,mhennings/marcohennings-go,sanjosh/sanjos100-tipc,bryanxu/go-zh,bryanxu/go-zh,rflanagan/reginaldflanagan-project1,rflanagan/reginaldflanagan-project1,rdp/rogerpack2005-golang,bryanxu/go-zh,webfd/go-zh,scirelli/scirelli-go,rflanagan/reginaldflanagan-project1,mhennings/marcohennings-go,d0f/go-zh,webfd/go-zh,Triskite/willstone-goclone,webfd/go-zh,glycerine/jeaten-go-arrayof-structof,d0f/go-zh,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,rflanagan/reginaldflanagan-project1,rdp/rogerpack2005-golang,bryanxu/go-zh,d0f/go-zh,bryanxu/go-zh,scirelli/scirelli-go,Triskite/willstone-goclone,glycerine/jeaten-go-arrayof-structof,Triskite/willstone-goclone,mhennings/marcohennings-go,glycerine/jeaten-go-arrayof-structof,glycerine/jeaten-go-arrayof-structof,webfd/go-zh,bryanxu/go-zh,sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc,webfd/go-zh,rflanagan/reginaldflanagan-project1,rdp/rogerpack2005-golang,webfd/go-zh,scirelli/scirelli-go,glycerine/jeaten-go-arrayof-structof,rdp/rogerpack2005-golang,scirelli/scirelli-go,Triskite/willstone-goclone,rflanagan/reginaldflanagan-project1,Triskite/willstone-goclone,sanjosh/sanjos100-tipc,sanjosh/sanjos100-tipc,webfd/go-zh,rflanagan/reginaldflanagan-project1,rdp/rogerpack2005-golang,mhennings/marcohennings-go,d0f/go-zh,d0f/go-zh,Triskite/willstone-goclone,rdp/rogerpack2005-golang,rdp/rogerpack2005-golang,rflanagan/reginaldflanagan-project1,d0f/go-zh,d0f/go-zh,mhennings/marcohennings-go,webfd/go-zh,scirelli/scirelli-go,sanjosh/sanjos100-tipc,scirelli/scirelli-go,sanjosh/sanjos100-tipc,scirelli/scirelli-go,mhennings/marcohennings-go,bryanxu/go-zh,mhennings/marcohennings-go,sanjosh/sanjos100-tipc