[Info-vax] Bliss was Re: Learning VMS application programming

[Johnny Billquist]

On 2014-09-10 15:24, John Reagan wrote:
> On Wednesday, September 10, 2014 9:05:50 AM UTC-4, Bob Koehler wrote:
>
>>     Macro-11 and Macro-32 I can understand.  But Macro-10 was one of
>>     the most different I've worked with, out of several.
>
> The assembler or the instruction set?

I think the assembler differed more, but of course there isn't much 
similarity in the instruction set either. But then again, it's all 
assembler, and if you just look at it that way, it is not really that 
different. You have some registers. You move data around. You compare 
data. You jump around. And that's about it...

> The assembler's ability to have code literals looks confusing to new reader.   It had lambda routines years before Python or C++.  Plus using "dot" in those nested literals often gave you results you didn't expect.  (but then again, it is an assembler - it is supposed to have sharp edges!)

Agreed. MACRO-10 do stuff that you'd definitely never find in MACRO-11 
or MACRO-32.

> For me, I always found it funny that the instruction set had a jump instruction (spelled JUMP) that did not jump.  I never understood why that form (other than just simplicity to implement in hardware).

Well, the JUMP doing no jump is totally in line with the instruction set 
as a whole, and is very consistent. If you look at the opcodes it is 
pretty obvious.
There is not only JUMP, you also have SKIP (which do not skip), and so on.
Any conditional instruction have the "never" condition. The PDP-10 is 
very consistent.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
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