Personal Computer User Manual

Multiprocessor Support
MVME197LEIG/D1 3-15
3
Network Boot Control Module
The “control” capability of the Network Boot Control Module is needed to tie
together all the necessary modules (capabilities) and to sequence the booting
process. The booting sequence consists of two phases: the first phase is labeled
“address determination and bootfile selection” and the second phase is labeled
“file transfer”. The first phase will utilize the RARP/BOOTP capability and the
second phase will utilize the TFTP capability.
Network I/O Error Codes
197Bug returns an error code if an attempted network operation is
unsuccessful.
Multiprocessor Support
The MVME197LE dual-port RAM feature makes the shared RAM available to
remote processors as well as to the local processor. This can be done by either
of the following two methods. Either method can be enabled/disabled by the
ENV command as its Remote Start Switch Method (refer to Appendix A).
Multiprocessor Control Register (MPCR) Method
A remote processor can initiate program execution in the local MVME197LE
dual-port RAM by issuing a remote GO command using the Multiprocessor
Control Register (MPCR). The MPCR, located at shared RAM location of $3000
offset from the base address the debugger loads it at, contains one of two
words used to control communication between processors. The MPCR
contents are organized as follows:
The status codes stored in the MPCR are of two types:
– Status returned (from the monitor)
– Status set (by the bus master)
The status codes that may be returned from the monitor are:
HEX 0 (HEX 00) Wait. Initialization not yet complete.
ASCII R (HEX 52) Ready. The firmware monitor is watching for
a change.
ASCII E (HEX 45) Code pointed to by the MPAR address is
executing.
$3000 * N/A N/A N/A (MPCR)