[Info-vax] Userland programming languages on VMS.

[Dave Froble]

On 1/31/2022 3:33 AM, Johnny Billquist wrote:
> On 2022-01-31 01:43, Arne Vajhøj wrote:
>> On 1/30/2022 7:19 PM, Simon Clubley wrote:
>>> On 2022-01-29, Arne Vajhøj <arne at vajhoej.dk> wrote:
>>>> On 1/29/2022 1:53 AM, George Cornelius wrote:
>>>>>
>>>>> Works on Eisner.
>>>>>
>>>>> $ show sys/noproc
>>>>> OpenVMS V8.4-2L2  on node EISNER   29-JAN-2022 [...]
>>>>>
>>>>> Here's the memory layout synopsis from a linker map:
>>>>>
>>>>> Virtual memory allocated:                         00010000 0005FFFF
>>>>> 00050000 (327680. bytes, 640. pages)
>>>>> 64-Bit Virtual memory allocated:                  00000000 00000000 00000000
>>>>>                                                     80000000 80010000
>>>>> 00010000 (65536. bytes, 128. pages)
>>>>>
>>>>> The example, though, shows too small an allocation to escape 32 bit address
>>>>> space.
>>>>
>>>> I consider 0000000080000000 to be 64 bit space.
>>>>
>>>> 0000000000000000 - 000000007FFFFFFF is P0 and P1 space
>>>> FFFFFFFF80000000 - FFFFFFFFFFFFFFFF is S0 and S1 space
>>>> 0000000080000000 and upward is P2 space
>>>>
>>>
>>> I think George's point is that this specific address can be
>>> represented in a 32-bit pointer.
>>
>> It can't.
>>
>> A 32 bit pointer with the value 80000000 will end up as
>> FFFFFFFF80000000.
>
> Since when are pointers considered to be signed and need sign extension?
>
>   Johnny

When one is using a signed integer to store the value of the pointer.

Hey, you asked ...

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