TOPS-10 Monitor Calls Manual Volume 2 AA-K039D ... - Trailing-Edge

PIINI [CALLI 135]
22.124 PIINI. [CALLI 135]
FUNCTION
Initializes the programmable software interrupt (PSI) facility by
clearing any old interrupts and storing the base address of the
interrupt vector block. Refer to Chapter 6 for more information about
using the PSI system.
CALLING SEQUENCE
MOVE ac, [flag + addr]
PIINI. ac,
error return
skip return
addr:
interrupt vector block address
In the calling sequence, the program supplies the following variables:
o
flag is one or more of the following:
Bits
o
1
Symbol
PS.UCS
PS.IEA
Meaning
Use the current (PC) section for the vector
section. (IFIW) If PS.UCS is not set, addr
is treated as a 30-bit address. This bit
is ignored if PS.IEA is not set.
Use extended addressing format. A 30-bit
PC word is stored in the old PC location in
the PSI block when an interrupt occurs. No
flags are stored in the PC. Flags are
stored in the monitor, and may be returned
using the PIFLG. UUO.
If PS.IEA is clear, the entire contents of
the left half of the ac will be ignored.
o
addr is the base address of the first interrupt vector block
(described below) .
The interrupt vector block is a list of one or more sub-blocks, each
of which is formatted as follows:
Offset
o
1
Symbol
.PSVNP
.PSVOP
Contents
New program counter; this is the address of the
interrupt service routine. This value is set by
the prog~m. The program supplies a 30-bit
address if you have not set PS.IEA (above). If
PS.IEA is not set, the left-hand half of this word
is ignored.
Old program counter; this is the address of the
next instruction after the instruction that was
being executed when the interrupt occurred. This
value is returned by the monitor on a interrupt.
If the instruction was a monitor call, .PSVOP
contains the return address for the calli however,
if the monitor terminated the call, .PSVOP
contains the address of the call itself.
22-309