[Info-vax] Bounce buffers, was: Re: $sndopr() and dsc64$descriptor

[Simon Clubley]

On 2021-03-12, John Reagan <xyzzy1959 at gmail.com> wrote:
> For those of you keeping score at home, I checked the sources (Macro-32) and it seems to only deal with 32-bit descriptors.  Since the $SND* services use descriptors to describe non-strings, the internal consumers would also need to handle 64-bit addresses and/or lengths > 64K.  I guess it is the 64-bit addresses that is the "most common" request (ie, this thread).   I think we can deliver this change at the same time we ship object-oriented BASIC.
>

Interesting. I think David is going to look forward to playing with
OO Basic from next month. :-)

On a more serious note, has anyone ever considered implementing a
bounce buffer in the system service interface for these problem
system services ?

How easy would it be to mark a specific system service as being 32-bit
only so the system service interface could implement a bounce buffer
and do the copying to and from the user's buffer as required if the
user's buffer was outside of the 32-bit address range ?

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.