* [TUHS] Happy birthday, PDP-8!
@ 2017-03-27 0:31 Noel Chiappa
2017-03-27 0:37 ` Arthur Krewat
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Noel Chiappa @ 2017-03-27 0:31 UTC (permalink / raw)
> From: Dave Horsfall
> And as for subroutine calls on the -8, let's not go there... As I dimly
> recall, it planted the return address into the first word of the called
> routine and jumped to the second instruction; to return, you did an
> indirect jump to the first word.
That do be correct.
That style of subroutine call goes back a _long_ way. IIRC, Whirlwind used
that kind of linkage (alas, I've misplaced my copy of the Whirlwind
instruction manual, sigh - a real tresure).
ISTVR there was something about the way Whirlwind did it that made it clear
how it came to be the way it was - IIRC, the last instruction in the
subroutine was normally a 'jump to literal' (i.e. a constant, in the
instruction), and the Whirlwind 'jump to subroutine' stored the return address
in a register; there was a special instruction (normally the first one in any
subroutine) that stored the low-order N bits of that register in the literal
field of the last instruction: i.e. self-modifying code.
The PDP-6 (of which the PDP-10 was a clone) was on the border of that period;
it had both types of subroutine linkage (store the return in the destination,
and jump to dest+1; and also push the return on the stack).
Noel
^ permalink raw reply [flat|nested] 6+ messages in thread
* [TUHS] Happy birthday, PDP-8!
2017-03-27 0:31 [TUHS] Happy birthday, PDP-8! Noel Chiappa
@ 2017-03-27 0:37 ` Arthur Krewat
2017-03-27 12:05 ` Tim Bradshaw
2017-03-27 13:45 ` [TUHS] Subroutine calling conventions - was " Toby Thain
2 siblings, 0 replies; 6+ messages in thread
From: Arthur Krewat @ 2017-03-27 0:37 UTC (permalink / raw)
Um. More like a natural progression.
Like 8086->80186->80286->80386->80486->...
On 3/26/2017 8:31 PM, Noel Chiappa wrote:
> The PDP-6 (of which the PDP-10 was a clone)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [TUHS] Happy birthday, PDP-8!
2017-03-27 0:31 [TUHS] Happy birthday, PDP-8! Noel Chiappa
2017-03-27 0:37 ` Arthur Krewat
@ 2017-03-27 12:05 ` Tim Bradshaw
2017-03-27 13:35 ` Tony Finch
2017-03-27 21:37 ` Terry Smith
2017-03-27 13:45 ` [TUHS] Subroutine calling conventions - was " Toby Thain
2 siblings, 2 replies; 6+ messages in thread
From: Tim Bradshaw @ 2017-03-27 12:05 UTC (permalink / raw)
On 27 Mar 2017, at 01:31, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
>
>
> That style of subroutine call goes back a _long_ way. IIRC, Whirlwind used
> that kind of linkage (alas, I've misplaced my copy of the Whirlwind
> instruction manual, sigh - a real tresure).
This is how subroutines worked on EDSAC. It might go back further than this, but it can't go back much further.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [TUHS] Happy birthday, PDP-8!
2017-03-27 12:05 ` Tim Bradshaw
@ 2017-03-27 13:35 ` Tony Finch
2017-03-27 21:37 ` Terry Smith
1 sibling, 0 replies; 6+ messages in thread
From: Tony Finch @ 2017-03-27 13:35 UTC (permalink / raw)
Tim Bradshaw <tfb at tfeb.org> wrote:
>
> This is how subroutines worked on EDSAC. It might go back further than
> this, but it can't go back much further.
I found this rather good survey of early subroutine linkage:
https://people.cs.clemson.edu/~mark/subroutines.html
Turing designed a stack-based linkage for the ACE, a few years before
Wheeler invented the EDSAC subroutine linkage.
Tony.
--
f.anthony.n.finch <dot at dotat.at> http://dotat.at/ - I xn--zr8h punycode
Irish Sea: East, veering south later, 4 or 5. Smooth or slight, occasionally
moderate later in south. Showers later. Good.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [TUHS] Subroutine calling conventions - was Re: Happy birthday, PDP-8!
2017-03-27 0:31 [TUHS] Happy birthday, PDP-8! Noel Chiappa
2017-03-27 0:37 ` Arthur Krewat
2017-03-27 12:05 ` Tim Bradshaw
@ 2017-03-27 13:45 ` Toby Thain
2 siblings, 0 replies; 6+ messages in thread
From: Toby Thain @ 2017-03-27 13:45 UTC (permalink / raw)
On 2017-03-26 8:31 PM, Noel Chiappa wrote:
> > From: Dave Horsfall
>
> > And as for subroutine calls on the -8, let's not go there... As I dimly
> > recall, it planted the return address into the first word of the called
> > routine and jumped to the second instruction; to return, you did an
> > indirect jump to the first word.
>
> That do be correct.
>
> That style of subroutine call goes back a _long_ way. IIRC, Whirlwind used
> that kind of linkage (alas, I've misplaced my copy of the Whirlwind
> instruction manual, sigh - a real tresure).
This link arrived in my twitter feed this morning.
https://people.cs.clemson.edu/~mark/subroutines.html
--T
>
> ISTVR there was something about the way Whirlwind did it that made it clear
> how it came to be the way it was - IIRC, the last instruction in the
> subroutine was normally a 'jump to literal' (i.e. a constant, in the
> instruction), and the Whirlwind 'jump to subroutine' stored the return address
> in a register; there was a special instruction (normally the first one in any
> subroutine) that stored the low-order N bits of that register in the literal
> field of the last instruction: i.e. self-modifying code.
>
> The PDP-6 (of which the PDP-10 was a clone) was on the border of that period;
> it had both types of subroutine linkage (store the return in the destination,
> and jump to dest+1; and also push the return on the stack).
>
> Noel
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [TUHS] Happy birthday, PDP-8!
2017-03-27 12:05 ` Tim Bradshaw
2017-03-27 13:35 ` Tony Finch
@ 2017-03-27 21:37 ` Terry Smith
1 sibling, 0 replies; 6+ messages in thread
From: Terry Smith @ 2017-03-27 21:37 UTC (permalink / raw)
We had a PDP 8E and an 8I at Humber College back in the day. I used to
play chess against Chekmo2 on it on paper tape.
On 2017-03-27 08:05 AM, Tim Bradshaw wrote:
> On 27 Mar 2017, at 01:31, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
>>
>> That style of subroutine call goes back a _long_ way. IIRC, Whirlwind used
>> that kind of linkage (alas, I've misplaced my copy of the Whirlwind
>> instruction manual, sigh - a real tresure).
> This is how subroutines worked on EDSAC. It might go back further than this, but it can't go back much further..
>
^ permalink raw reply [flat|nested] 6+ messages in thread
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2017-03-27 0:31 [TUHS] Happy birthday, PDP-8! Noel Chiappa
2017-03-27 0:37 ` Arthur Krewat
2017-03-27 12:05 ` Tim Bradshaw
2017-03-27 13:35 ` Tony Finch
2017-03-27 21:37 ` Terry Smith
2017-03-27 13:45 ` [TUHS] Subroutine calling conventions - was " Toby Thain
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