Z80 trst circuit

Z80 trst circuit

[Luke A. Guest]

Hi,

Just thought I'd post my first iterations of the Z80 test circuit.

https://youtu.be/WIz5J6fmplo

Re: Z80 trst circuit

[erlo]

On 27-01-2016 11:26, Luke A. Guest wrote:
> 
> 
> Hi,
> 
> Just thought I'd post my first iterations of the Z80 test circuit.
> 
> https://youtu.be/WIz5J6fmplo
> 
What is the Ada angle on this?

Erlo

Re: Z80 trst circuit

[Randy Brukardt]

"erlo" <erlo@valid.not> wrote in message news:n8b8s4$tme$1@dont-email.me...
> On 27-01-2016 11:26, Luke A. Guest wrote:
>>
>>
>> Hi,
>>
>> Just thought I'd post my first iterations of the Z80 test circuit.
>>
>> https://youtu.be/WIz5J6fmplo
>>
> What is the Ada angle on this?

?? Janus/Ada 83 targeted CP/M Z80 machines back when they were common (that 
was our first commercial compiler, as the IBM PC and MS-DOS hadn't been 
introduced yet -- showing my age, I guess ;-). So it's certainly possible to 
program in Ada on such machines, but I don't know if anyone has done so in 
decades (I think we stopped selling those versions around 1987).

                                Randy.

Re: Z80 trst circuit

[Luke A. Guest]

Randy Brukardt <randy@rrsoftware.com> wrote:
> "erlo" <erlo@valid.not> wrote in message news:n8b8s4$tme$1@dont-email.me...
>> On 27-01-2016 11:26, Luke A. Guest wrote:
>>> 
>>> 
>>> Hi,
>>> 
>>> Just thought I'd post my first iterations of the Z80 test circuit.
>>> 
>>> https://youtu.be/WIz5J6fmplo
>>> 
>> What is the Ada angle on this?
> 
> ?? Janus/Ada 83 targeted CP/M Z80 machines back when they were common (that 
> was our first commercial compiler, as the IBM PC and MS-DOS hadn't been 
> introduced yet -- showing my age, I guess ;-). So it's certainly possible to 
> program in Ada on such machines, but I don't know if anyone has done so in 
> decades (I think we stopped selling 

I reckon it'd be doable with GNAT, someone ported GCC to the 6502 ffs!
That's got less registers than the Z80, but it does use zero page in STAM
for virtual registers, which a AFAICT can't be used on Z80. 

I also think using pragma restrictions heavily here would help, also other
pragma a for restricting what gets generated, ie names.

Do you have Any advice re this?

Re: Z80 trst circuit

[Randy Brukardt]

"Luke A. Guest" <laguest@archeia.com> wrote in message 
news:652916932.475662642.036346.laguest-archeia.com@nntp.aioe.org...
> Randy Brukardt <randy@rrsoftware.com> wrote:
>> "erlo" <erlo@valid.not> wrote in message 
>> news:n8b8s4$tme$1@dont-email.me...
>>> On 27-01-2016 11:26, Luke A. Guest wrote:
>>>>
>>>>
>>>> Hi,
>>>>
>>>> Just thought I'd post my first iterations of the Z80 test circuit.
>>>>
>>>> https://youtu.be/WIz5J6fmplo
>>>>
>>> What is the Ada angle on this?
>>
>> ?? Janus/Ada 83 targeted CP/M Z80 machines back when they were common 
>> (that
>> was our first commercial compiler, as the IBM PC and MS-DOS hadn't been
>> introduced yet -- showing my age, I guess ;-). So it's certainly possible 
>> to
>> program in Ada on such machines, but I don't know if anyone has done so 
>> in
>> decades (I think we stopped selling
>
> I reckon it'd be doable with GNAT, someone ported GCC to the 6502 ffs!
> That's got less registers than the Z80, but it does use zero page in STAM
> for virtual registers, which a AFAICT can't be used on Z80.
>
> I also think using pragma restrictions heavily here would help, also other
> pragma a for restricting what gets generated, ie names.
>
> Do you have Any advice re this?

Not really. Ada 2012 is way different than the subset of Ada 83 that we had 
on the Z80. I don't remember off-hand precisely what Ada features were 
available on that compiler; I know we had some software floating point, and 
certainly not any tasking. But certainly there wasn't anything like tagged 
types, or dispatching, or preconditions.

                                                        Randy. 

Re: Z80 trst circuit

[Luke A. Guest]

Randy Brukardt <randy@rrsoftware.com> wrote:

>> Do you have Any advice re this?
> 
> Not really. Ada 2012 is way different than the subset of Ada 83 that we had 
> on the Z80. I don't remember off-hand precisely what Ada features were 
> available on that compiler; I know we had some software floating point, and 
> certainly not any tasking. But certainly there wasn't anything like tagged 
> types, or dispatching, or preconditions.

You can definitely do multitasking on Z80, I've seen projects that do it,
they use memory banking to implement it though.

Luke.

Re: Z80 trst circuit

[Randy Brukardt]

"Luke A. Guest" <laguest@archeia.com> wrote in message 
news:2084722069.475747788.515903.laguest-archeia.com@nntp.aioe.org...
> Randy Brukardt <randy@rrsoftware.com> wrote:
>
>>> Do you have Any advice re this?
>>
>> Not really. Ada 2012 is way different than the subset of Ada 83 that we 
>> had
>> on the Z80. I don't remember off-hand precisely what Ada features were
>> available on that compiler; I know we had some software floating point, 
>> and
>> certainly not any tasking. But certainly there wasn't anything like 
>> tagged
>> types, or dispatching, or preconditions.
>
> You can definitely do multitasking on Z80, I've seen projects that do it,
> they use memory banking to implement it though.

It's surely possible; we did it on the 8086 using early MS-DOS, and that's 
essentially the same sort of hardware (with a 16-times bigger address 
space). And it's the address space that's the problem; our task runtime 
takes up approximately 32K on the 8086, but of course on a pure 16-bit 
processor that would leave almost no space for the program. (The rest of the 
runtime was around 4K, if I remember right.) I'm sure you could do better 
with a Ravenscar task supervisor (that of course didn't exist in 1984), but 
it still would be a substantial amount of the code space available.

We used the equivalent of memory banking to expand the data space on 8086 
processors (it allows our 16-bit compilers to compile programs about 3 times 
larger than they otherwise could), but using that with code would be very 
difficult. <Shivers>

                        Randy.

Re: Z80 trst circuit

[erlo]

On 28-01-2016 01:26, Randy Brukardt wrote:

> ?? Janus/Ada 83 targeted CP/M Z80 machines back when they were common (that 
> was our first commercial compiler, as the IBM PC and MS-DOS hadn't been 
> introduced yet -- showing my age, I guess ;-). So it's certainly possible to 
> program in Ada on such machines, but I don't know if anyone has done so in 
> decades (I think we stopped selling those versions around 1987).
> 
>                                 Randy.
> 
> 
> 
And the sources for CP/M are available, both 2.2 and 3.0 as far as i know.
I did quite some Z80 programming in the earlier days, both on CP/M and
assembler on the bare iron. Shows my age too ;o)
I always liked the Z80 for some reason.

Erlo

Re: Z80 trst circuit

[patrick]

Hi Erlo

Luke has been tinkering with Ada runtimes to make them available to smaller devices. Even if your not into the Z80, the code will be valuable for other devices as the runtime and compilation process for his experiments could be reused for other targets.

-Patrick

Re: Z80 trst circuit

[erlo]

On 28-01-2016 01:58, patrick@spellingbeewinnars.org wrote:
> Hi Erlo
> 
> Luke has been tinkering with Ada runtimes to make them available to smaller devices. Even if your not into the Z80, the code will be valuable for other devices as the runtime and compilation process for his experiments could be reused for other targets.
> 
> -Patrick
> 

I wasn't aware of this. Then it starts to make sense. Z80 was/is a nice
processor to work with.

Erlo

Re: Z80 trst circuit

[patrick]

Hi Erlo

Luke has been tinkering with Ada runtimes to make them available to smaller devices. Even if your not into the Z80, the code will be valuable for other devices as the runtime and compilation process for his experiments could be reused for other targets.

-Patrick