[Info-vax] Listeners in VMS Basic, was: Re: Integrity iLO Configuration?

[Dave Froble]

On 7/12/2021 7:43 PM, abrsvc wrote:
> On Monday, July 12, 2021 at 7:13:08 PM UTC-4, Dave Froble wrote:
>> On 7/12/2021 4:16 PM, Stephen Hoffman wrote:
>>> On 2021-07-09 23:45:31 +0000, Dave Froble said:
>>>
>>>> Just because some agree, doesn't make them right.
>>>>
>>>> But, Ok, a practical example, tell me, too many comments, not enough
>>>> comments, what?
>>>>
>>>> ;+
>>>> ; Base block must be > 0
>>>> ; # of blocks must be > 0 & < 128
>>>> ; End block must be <= EOF block
>>>> ; Grant lock if caller has exclusive access to the file
>>>> ;-
>>>>
>>>> MOVZWL #SS$_ABORT,R0 ; Assume failure
>>>> TSTL R3 ; Base block zero?
>>>> BNEQU 020$ ; No, continue
>>>> 010$: BRW RETURN ; Yes, return
>>>> 020$: TSTL R4 ; Block count zero?
>>>> BEQLU 010$ ; Yes, return
>>>> CMPL #127,R4 ; Block count <= 127
>>>> BLSSU 010$ ; No, return
>>>> MOVAB -1(R3)[R4],R5 ; Last block to lock
>>>> CMPL CIB_L_FILSIZ(R7),R5 ; LE filesize?
>>>> BGEQU 030$ ; Yes, continue
>>>> MOVL CIB_L_FILSIZ(R7),R5 ; Else lock only to EOF
>>>
>>>
>>> BLEQU, not BLSSU? Or BLSSU with 128?
>>>
>>> I'd suggest using a string constant for 127 (or 128) rather than a magic
>>> number, too.
>>>
>>>
>> Now I'm sorry I started this ...
>>
>> Ok, could you expound upon your comments? I'm totally not understanding.
>>
>> This particular code is from 1984, and written by Ben Carter, a much
>> better Macro-32 programmer than I have ever been.
>> --
>> David Froble Tel: 724-529-0450
>> Dave Froble Enterprises, Inc. E-Mail: da... at tsoft-inc.com
>> DFE Ultralights, Inc.
>> 170 Grimplin Road
>> Vanderbilt, PA 15486
>
> I think the issue is more of style than anything else.  This is kind of like opposite logic in higher level languages.
> How often have you seen if statements like:  If z .ge.20 then...  Where: If Z .lt. 20 then  could be used with different code.   Both statements differentiate the value at the same point.  Perhaps using less than makes more sense given the code stream where greater or equal does not?  Context is important here.
>
> In your code segment, maybe the 127 makes more sense as a pivot point where 128 does not.

The database code allows transfers up to 127 blocks.  Sure looks right 
to me.

> In regards to the use of a constant:  I get it as using a constant allows for a name that may mean something rather than just hte value.
>

Ok, I understand.  Not necessarily agree.

-- 
David Froble                       Tel: 724-529-0450
Dave Froble Enterprises, Inc.      E-Mail: davef at tsoft-inc.com
DFE Ultralights, Inc.
170 Grimplin Road
Vanderbilt, PA  15486