The HGPR option controls the compiler usage of the 64-bit registers provided by IBM® z/Architecture® processors.

HGPR option syntax

Read syntax diagramSkip visual syntax diagramHGPR(PRESERVENOPRESERVE)

Default is: HGPR(PRESERVE)

Abbreviations are: None

The Enterprise COBOL compiler uses the 64-bit width of the IBM z/Architecture General Purpose Registers (GPRs). HGPR stands for "High-halves of 64-bit GPRs", which means the use of native 64-bit instructions.

If you specify HGPR(PRESERVE), the compiler preserves the high halves of the 64-bit GPRs that a program 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 of the program is not Enterprise COBOL, Enterprise PL/I, or z/OS® XL C/C++ compiler-generated code.
If you specify HGPR(NOPRESERVE), the compiler omits preserving the high-halves of the 64-bit GPRs that a program is using, which improves performance.

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