ACLE/SIMD32: add `ssub8` and `usub8`#696

Merged

gnzlbg merged 2 commits intorust-lang:masterfrom

paoloteti:arm-dsp

Feb 27, 2019

Commits on Feb 23, 2019

ACLE/SIMD32: add `ssub8` and `usub8`
paoloteti
committed

Commits on Feb 25, 2019

The GE bits of the APSR are set also by USUB8
paoloteti
committed