User`s manual

SBCSCSI/D1C-1

EXTERNAL ROUTINES

Introduction

The SCSI Software requires services to be provided external to the SCSI

Software itself. These services must be provided by the specific application.

There are two global services which must be provided:

splhi A routine used to mask interrupts from the NCR 53C710 SCSI

chip. This may be a null routine if the specific application of

the SCSI Software uses the software in polled mode (i.e., at

interrupt level 0).

splx A companion routine to splhi, used to restore interrupts to

the level existing before the corresponding splhi. This may be

a null routine if the specific application of the SCSI Software

uses the software in polled mode (i.e., at interrupt level 0).

Also, a command-specific service must be provided:

ret_stat A routine called by the Firmware to notify the user that final

status is available for a command request. A pointer to this

routine is supplied in each command structure (siop_struc)

issued to the Firmware.

Firmware for the MVME197 also requires routines to enforce serialized access

to I/O registers:

serialize_memory_access

deserialize_memory_access

When compiling to run on that board (refer to the file incl/sfw_cnfg.h), the

user-supplied routines set/clear the

SRM (serialize memory) bit in the 88110 PSR

(processor status register). If one compiled object may be executed on both an

88100 and an 88110, then those routines should verify that the processor is an

88110.

All of the above routines are described further on the following pages.