Available on

**ARM**only.## Expand description

Inserts a `USUB8`

instruction.

Returns the 8-bit unsigned equivalent of

res[0] = a[0] - a[0] res[1] = a[1] - a[1] res[2] = a[2] - a[2] res[3] = a[3] - a[3]

where [0] is the lower 8 bits and [3] is the upper 8 bits. The GE bits of the APSR are set.