Re: A Packed-Decimal Machine? (was Entry Parameters)

[Jon.Paris@xxxxxxxxxx]

 >> You've gotta be joking me!

Nope - that's pretty much it.  Forget parameters and just take simple case of a
field stored in a DS as type B.  Note I'm using "type" because I and U are also
binary.

To multiply your field by another (assume packed) the compiler will generate:

Move field to packed temp
Multiply temp by second value
Move packed result to binary field.

This does not happen for types I and U.

Basic reason is that a B type is defined as having a specific number of digits.
For example a 4 digit B field will occupy 2 bytes.  But 2 bytes can accommodate
values up to 32K - well beyond the 9,999 capacity of a 4 digit field.  The
conversion to packed ensures that only 4 digits are passed into the calculation
and only four digits come out.  When you use types I and U the compiler assumes
you know what you are doing and don't need the safety blanket.  For the same
reasons you should always use I or U when an API specifies a field as binary
otherwise there is the possibility you will incur truncation.



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