Hi Tom,
You are going to have to implement your own routines. Perhaps check
out how Algol or PL/1 handle subroutine calls. But standard call
routines do not support re-entrant calls.
Rich
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Thank you for the info. I need to figure out how to implement your
suggestion. I found in the documentation on SAVE an option
SAVE (14,12),,xxxxxxx
where xxxx is a ds 18f area to save the regs. I am trying to figure
out if the change will work on DOS/VS rel 34.
Cheers
/tom c
On Wed, Oct 12, 2022 at 9:59 AM Richard Cornwell
<rich@...> wrote:
Hi Tom,
Typically 360/370 subroutine calls are done with a what is
called a save area. This is 18 words allocated within the
subroutine. On entry the registers are saved into the previous
routines save area. Then the base register is set up and the save
pointer is pointed to the current save area. On exit the registers
are restore, this will include the previous save area.
This means that if you call a subroutine again it will wipe out the
previous calls information. To do this properly you will either
need to allocate a bunch of memory to save all the registers in and
advance the save pointer for each call. The other option is to
allocate and free save areas at each call.
Basically you will need to implement some sort of stack to handle
function calls if you want true recursive calls.
Rich
