HP 3000 Manuals HP 3000 Manuals
ARITRAP Collectively enables or disables arithmetic traps.
NOTE When arithmetic traps are ignored (disabled) on MPE XL, the results are not guaranteed to be identical to those on MPE V/E. On MPE XL, a better way to prevent arithmetic traps is to use compiler directives, for example, $ovflcheck off$ in HP Pascal/XL. When compiler directives are used, the compiler generates arithmetic instructions that do not trap on overflow. This is a more natural way of preventing arithmetic traps. When arithmetic traps are ignored using ARITRAP, the trap actually takes place, but the MPE XL trap subsystem recovers from the trap and takes the action required to continue execution.
Syntax The ARITRAP intrinsic is called as follows: ARITRAP(trapstate); Parameters The ARITRAP intrinsic has one required parameter: trapstate 32-bit signed integer by value (required) A value enabling or disabling arithmetic traps. Enter 0 if you want to disable arithmetic traps or 1 if you want to enable all traps except the IEEE inexact result trap.
NOTE By default, all traps except IEEE floating-point exceptions are enabled, and the system trap handler is armed. Many floating-point operations result in an inexact result. Consequently, most compiler libraries doing floating-point operations will result in an inexact trap if the IEEE Inexact Result trap is enabled. Therefore, you should enable the IEEE Inexact Result trap (using the HPENBLTRAP intrinsic) only if absolutely necessary.
Condition Codes The ARITRAP intrinsic can return one of the following condition codes: CCE Request granted. All arithmetic traps were originally disabled. CCG Request granted. At least one arithmetic trap was originally enabled. CCL Not returned by this intrinsic.