10 Apr
2026
10 Apr
'26
4:19 p.m.
On 10/04/2026 16.13, Mark Matlock wrote:
Dave,
Johnny reminded me about a limitation of this FPEM, specifically it does not work
with tasks that have external headers. When you TKB your F77 program add the /-XH switch
to make a task that does not have an external header. RSX11M+ by default would have /XH on
by default.
That's what I found in the code. There was also some conditional about
external headers, so it's a little confusing. But I didn't see it having
any proper handling of external headers, so I would probably say don't
use them.
As I recall (maybe wrongly), you don’t have to
specify F77EIS when building the task, as long as FPEM is running. Also, if you needFPEM
to remove itself, I think you can UNStop it and it will change the vectors back. I am
interested in whether this will work on RSX11M+ V4.6
No. You also need F77EIS when using FPEM. The reason is that otherwise
the initialization tries to setup an FPP AST, which RSX gives an error
about if you don't have an FPP.
You should also build a kernel without FPP support, since FPEM will not
handle traps for FPP instructions in the kernel, and will completely
crash you out then. And finally, you do need to build the tasks with
/FP, so that the task header contains the storage for the FPP information.
These are some of the reasons I think it would be interesting to develop
another FP emulation, but one that is more complete and which would work
with a FP-enabled kernel.
Johnny