Format: FDSXF dest, source.

Phase0: FDSXF FT0, S0{.NEG}{.ABS}

Phase1: FDSXF FT1, S3{.NEG}{.ABS}

Phase2: -

Description: Gradient in x direction, one source

If (Pix0, Pix1) D = Pix1 – Pix0

If (Pix2, Pix3) D = Pix3 – Pix2

(DX 11 version)