HP 3000 Manuals HP 3000 Manuals
Step One: Remove Hardware Dependencies Many SPL constructs are highly hardware-dependent, such as ASSEMBLE statements and references to hardware registers. In most cases, these constructs were used by SPL programmers for reasons of efficiency, not for lack of higher level alternatives. Rewriting these portions and testing the program again should be a first step. Normally, this is a matter of determining exactly what the old statements are intended to do, and implementing the same function in SPL statements that do not depend on specific hardware instructions or registers. The direct use of the stack, via PUSH, DEL, and TOS operators is done for one of two reasons: either to avoid declaring temporary variables, or to retrieve information left on the stack after an operation such as SCAN. In the first case, simply declaring extra variables will allow the stack references to be eliminated. In the case of operations such as SCAN, see the relevant areas of this guide for SPL procedures that isolate these operations and may later be replaced by equivalent HP C/XL functions.