Thomas David Rivers
2017-09-26 16:47:40 UTC
I was hoping to determine if a program is allowed
to use the Additional Floating Point (AFP) registers.
There are two qualifications for this; first the "basic floating point
extensions"
has to be installed (which can be assumed after OS/390 2.6) and
second, the AFP CONTROL BIT of Control Register 0 has to be enabled
(bit #13.)
So - while the hardware allows it, it's possible - for some reason or
other -
the control register disallows it.
I'm looking around in the various locations (CVT, PSA, etc...) and hunting
for a mechanism where an application program can ask "Am I allowed to
use all 16 floating-pt registers, or am I restricted to the traditional 4?"
Is there an assembler service somewhere that provides the value of control
registers? You can just use STORE CONTROL (STCTL) instruction as it is
privileged.
- Many thanks -
- Dave Rivers -
to use the Additional Floating Point (AFP) registers.
There are two qualifications for this; first the "basic floating point
extensions"
has to be installed (which can be assumed after OS/390 2.6) and
second, the AFP CONTROL BIT of Control Register 0 has to be enabled
(bit #13.)
So - while the hardware allows it, it's possible - for some reason or
other -
the control register disallows it.
I'm looking around in the various locations (CVT, PSA, etc...) and hunting
for a mechanism where an application program can ask "Am I allowed to
use all 16 floating-pt registers, or am I restricted to the traditional 4?"
Is there an assembler service somewhere that provides the value of control
registers? You can just use STORE CONTROL (STCTL) instruction as it is
privileged.
- Many thanks -
- Dave Rivers -
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***@dignus.com Work: (919) 676-0847
Get your mainframe programming tools at http://www.dignus.com