Specifications

OpenVMS System Routines Called by OpenVMS AXP Device Drivers

IOC$CRAM_CMD

Return Values

SS$_NORMAL The calculated command, mask, and remote bus

address values have been written to the CRAM

and/or the speciﬁed buffer.

SS$_BADPARAM Illegal command supplied as input or illegal

argument supplied in call

SS$_INSFARG Insufﬁcient arguments supplied in call

Description

IOC$CRAM_CMD calculates the COMMAND, MASK, and RBADR ﬁelds for a

hardware I/O mailbox according to the requirements of a speciﬁc I/O interconnect.

It performs the following tasks:

• Obtains the address of the command table speciﬁc to the given I/O

interconnect from ADP$PS_COMMAND_TBL.

• Uses the value speciﬁed in the command argument as an index into the

command table to determine the corresponding command supported by the

I/O interconnect.

• If the command is valid for the I/O interconnect, IOC$CRAM_CMD writes it

to CRAM$L_COMMAND, to the speciﬁed buffer, or to both. If the command is

invalid for the I/O interconnect, IOC$CRAM_CMD returns SS$_BADPARAM

status to its caller.

• Calculates the RBADR and MASK ﬁelds based of the hardware I/O mailbox,

basing their values on the command, the address of device register interface

space (ADP$Q_CSR or IDB$Q_CSR, if the cram argument is speciﬁed), the

byte_offset argument, and interconnect-speciﬁc requirements. It writes

these values to CRAM$B_BYTE_MASK and CRAM$Q_RBADR, to the

speciﬁed buffer, or to both.

• Returns SS$_NORMAL status to its caller.

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