[Info-vax] Volatile, was: Re: yet another sys$qiow question

[VAXman- at SendSpamHere.ORG]

In article <mrg2hk$2m1$1 at dont-email.me>, Simon Clubley <clubley at remove_me.eisner.decus.org-Earth.UFP> writes:
>On 2015-08-24, George Cornelius <cornelius at eisner.decus.org> wrote:
>> [VAXMAN wrote:]
>>
>>>> 	TSTL	IOSB
>>>> 	BNEQ	10$
>>>> 20$:	BRB	20$
>>>> 10$:
>>
>> Actually, to test just the status in VMS you would use TSTW.  But
>> when testing for nonzero TSTL works as well and does not require
>> any extra word extraction code on the newer architectures.
>>
>
>BTW, on ARM you can conditionally execute the following instructions
>(not just jumps) based on the last test you did so no messy jumping
>such as the above is required if you are doing something a bit more
>more complicated than the above.
>
>However, I have a question about the above code. First off, it's been
>a couple of decades since I last wrote some MACRO-32 code so go easy
>if I've got this wrong. :-)
>
>Brian wrote:
>	TSTL	IOSB
>	BNEQ	10$
>20$:	BRB	20$
>10$:
>
>Couldn't you make that more efficient with:
>
>	TSTL	IOSB
>10$:
>	BEQ	10$	; Or whatever branch if equal to zero is on VAX
>
>It's not important; I'm just curious as that style is something which
>works on ARM just fine. I was just wondering if there's something on
>VAX I've forgotten about which stops the above from being usable.

Sheesh, I was merely parallelling Johnny's PDP macro example.

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