Subzero, MIPS32: Floating point load/store and format conversion instructions

Introducing instructions for floating point format conversion.
These instructions are needed for full implementation of lowerCast
and missing floating point arithmetic instruction frem.

BUG=
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/2024183002 .

Patch from Srdjan Obucina <Srdjan.Obucina@imgtec.com>.
4 files changed