Re: More on RPG style

Hi Sharon,

I think you're forgetting that there's a compiler and some microcode between the RPG source code and the actual logic circuit.

And from what I recall of x86 processors, to do a compare, a couple of registers are loaded and a compare instruction is issued. The hardware set a bit indicating whether the registers were equal or not (implemented by doing a subtract). The compiler writer (hi Barbara!) would probably implement "not =" and "<>" the same way.

Btw, my Engineering 101 instructor once said that you could implement an entire machine with a subtract operation...

*Peter Dow* /
Dow Software Services, Inc.
909 793-9050
pdow@xxxxxxxxxxxxxxx <mailto:pdow@xxxxxxxxxxxxxxx> /

On 3/1/2010 6:54 AM, Wintermute, Sharon wrote:

<> and NOT= are definitely NOT The same at the pure logical level.

Logic circuits don't work that way. By saying<> you are completing the
less than and the greater than test then making a decision based on both
results therefore making three tests.

Not = is only one test.



Sharon Wintermute
Sr. Software Engineer - Application Solutions
YRC Logistics
913.906.4309


-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Dennis Lovelady
Sent: Monday, March 01, 2010 8:46 AM
To: 'RPG programming on the IBM i / System i'
Subject: RE: More on RPG style

In general I would agree with you. But, when you are performing
multiple tests
and as soon as you fail the first one, it is generally acceptable to
return immediately.

On this point, we will not agree, then. But before I go: generally
acceptable by whom? By you, or by your firm, or by some standards
organization?

Some clients prefer 'Not =' to '<>'.
Not equal is only one logical test where '<>' is two logical tests.
Besides it is much easier to debug 'not =' vs '<>' when the previous
pgmr

<> and NOT = are equivalents, and fall under the "not" rule (in my
opinion).

If you can write =, then why do you need<>?

If a = b ;
Something() ;
Else ;
somethingElse() ;
Endif;

Rather than:
If a<> b ;


Dennis Lovelady
http://www.linkedin.com/in/dennislovelady
--
It's great to be smart 'cuz then you know stuff.