OPCOM - Open communication

General

Application areas:	Intertask communication; see "Intertask communication (ITC)"Communication; see "Communication (programs, users, system)"
Macro type:	Type O; see "O-type macros"

Macro description

The macro OPCOM allows the user to participate in intertask communication (ITC). The caller specifies a name, to be used as the ITC identification when sending or receiving messages. This name is entered in the ITC participants list, unless it is already being used by another ITC participant (see “Return information and error flags”, below).
The first participant to call the macro OPCOM implicitly causes ITC to be opened (a communication table is created).

Macro format and description of operands

OPCOM

name / (1)

name
Name which the caller wishes to use as an ITC name. This name may consist of up to 8 characters. Alphanumeric and special characters are permitted, except for:

X'00' through X'3F'X'41' through X'49'X'51' through X'59'X'62' through X'69'X'70' through X'79'X'80' through X'C0'X'CA' through X'D0'X'DA' through X'E1'X'EA' through X'EF'X'FA' through X'FE'

Character X'40' may only be specified as the last character of “name”.

(1)
Register R1 contains the address value of a field which contains the ITC name. Field length = 8 bytes.

Return information and error flags

R15:

+---------------+
|   |   |   |   |
| | | | | | |a|a|
+---------------+

A return code relating to the execution of the OPCOM macro is transferred in the rightmost byte of register R15.

X'aa'	Meaning
X' 00'	ITC participation opened
X' 04'	Operand error, ITC participation not opened
X' 08'	Name already in use, ITC participation not opened
X' 0C'	No system memory available to open ITC, or the internal maximum length for receive queues has been exceeded
X' 10'	ITC participation has already been enabled