No, to my knowledge NO compiler I ever came across (I worked on the dark side DOS BATCH, RT-11, RSX-11, and RSTS-11 in various languages though primarily MACRO-11 and FORTRAN) ever used this linkage. Certainly, none of the UNIX products did. It was goofy. We played around with it and it just didn’t do anything you couldn’t do better with JSR/RET and some clever stack manipulation with MOV instructions.

On Jan 5, 2016, at 12:43 PM, Clem Cole <clemc@ccc.com> wrote:

On Tue, Jan 5, 2016 at 12:28 PM, Ronald Natalie <ron@ronnatalie.com> wrote:
I remember going to the T11 (PDP-11 on a single chip) announcement and having them say the complete instruction set was supported with the exception of MARK.

right... which is why I don't think FTN use it, or the HW folks would have been forced to put it in.

Clem