Format: FDSYF dest, source.

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

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

Phase2: -

Description: Gradient in y direction, one source

If (Pix0, Pix2) D = Pix2 – Pix0

If (Pix1, Pix3) D = Pix3 – Pix1

(DX 11 version)