AFP
The AFP
option controls the compiler usage
of the Additional Floating Point (AFP) registers that are provided
by z/Architecture® processors.
Default is: AFP(NOVOLATILE)
Abbreviations are: None
The Enterprise COBOL compiler
generates code that uses the full complement of 16 floating point
registers (FPR) provided by a z/Architecture processor.
These FPRs are as follows:
- Original FPRs, which are numbered 0, 2, 4, and 6
- AFP registers, which are numbered 1, 3, 5, 7, and 8-15
AFP(VOLATILE)
- If you specify
AFP(VOLATILE)
, the AFP registers 8-15 are considered volatile, which means that they might be changed by a called subprogram. Therefore, the COBOL compiler generates extra code to protect the values in these registers. AFP(NOVOLATILE)
- If you specify
AFP(NOVOLATILE)
, the AFP registers 8-15 are considered nonvolatile, which means that they are known to be unchanged or preserved by every called subprogram. Therefore, the compiler can generate more efficient code sequences for programs with floating point operations. It is the normal z/OS® architecture convention.