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

[George Cornelius]

In article <mr792b$f9l$1 at Iltempo.Update.UU.SE>, Johnny Billquist <bqt at softjar.se> writes:
[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.

TSTW is precisely what the PDP-11 code would be, but in that case the
IOSB has only two words, one of which is status.

> Yeah, I suspected it should look like that, it's just that I have not 
> programmed in Macro-32 in many years, and instead of feeling foolish for 
> doing something stupid with some mnemonic, I stayed with what I know 
> even in my sleep, and expect you to rescue me. :-)
> 
> (There are just so many variants of the instructions on the VAX...)

The ultimate CISC implementation for quite a few years.  Surprising to
see polynomial evaluation as a single instruction, for example.

By comparison, without autoincrement/autodecrement and non- at Rn
indirection, the PDP-11 was almost RISClike.

George