RE: what is unclear - LEAVE

[Vernon Hamberg <hambergv@xxxxxxxxxxxxxx>]

Brad

At 10:14 AM 5/7/1998 -0500, you wrote:
>Don't even start the DOU/DOW thing.  But, I agree with Rick.  A priming
>read with a DOW is correct way to do it.  DOU will always do the loop
>once, which we don't want.

-snip-

>> > Heh
>> > And Hans even uses one of my favorite opcodes break to out of a DOU;
>> the
>> > LEAVE statement.

Speaking of whom—are any of the "language" constructs more efficient after
compilation? Does the optimizing compiler consolidate things. I mean, if an
'IF' inside a loop (that tests the same indicator) is not, in fact,
'optimized' out, then we have concrete reasons to use the venerable priming
read. But if the loop has no test but is only a block of code, we don't
have possible duplicate tests, right?

Opinions, history, etc., are interesting, but can we get some facts? I
think I'll go generate an IR (intermediate representation). Actually, that
might be interesting and even helpful. <bg>

At the end of it all, everything's a GOTO—ain't no such thing as structured
opcodes at the machine level, eh?

Cheers

Vernon Hamberg
Systems Software Programmer
Old Republic National Title Insurance Company
400 Second Avenue South
Minneapolis, MN  55401-2499
(612) 371-1111 x480


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