The HGPR option specifies that the compiler is permitted to
exploit 64-bit General Purpose Registers (GPRs) in 32-bit programs targeting z/Architecture hardware.

.-NOHGPR-------------------------.
>>-+-HGPR--+----------------------+-+--------------------------><
| .-NOPRESERVE-. |
'-(--+-PRESERVE---+--)-'
- PRESERVE
- PRESERVE Instructs the compiler to preserve the high halves of
the 64-bit GPRs that a function is using, by saving them in the prolog
for the function and restoring them in the epilog.
The PRESERVE suboption is necessary only if the caller is
not known to be Enterprise PL/I and/or the z/OS XL C/C++
compiler-generated code.
- NOPRESERVE
- NOPRESERVE lets the compiler omit preserving the high-halves of
the 64-bit GPRs that a function is using.
Because of performance considerations, the default suboption for HGPR is NOPRESERVE.
HGPR means "High-half of 64-bit GPR",
which refers to the use of native 64-bit instructions.
In particular, if the application use 8-byte integers, it should benefit from the native 64-bit instructions.
Note:
The NOHGPR option must be used in all CICS and SQL applications.
|
This information center is powered by Eclipse technology. (http://www.eclipse.org)