User`s manual

SBCSCSI/D14-1

NCR BUILD TOOLS

Introduction

The NCR build tools are a set of utilities provided to compile NCR SCSI

SCRIPTS source modules. The utilities provided are the SCRIPTS compiler

and the SCRIPTS preprocessor. The compiler, as written by the NCR

Corporation, is used to compile general purpose SCRIPTS source files into

executable NCR 53C710 machine instructions. The preprocessor, written

specifically for use in the Firmware environment, provides a mechanism

whereby SCRIPTS data references can be changed from the values assigned at

link time to new values defined dynamically at run time as required by the

Firmware.

SCSI SCRIPTS Data Reference Relocation

Because the siopdata data area required by the SIOP Firmware is dynamically

allocated, the references to this data area by SCRIPTS must then be changed

from the link time values through a patching process. This patching is done at

run-time by the siop_init() routine prior to SCRIPTS execution.

The SCRIPTS preprocessor utilities n710p68k and n710p80k are provided to

generate a relocation table used by siop_init() to perform this patch. This table

contains entries pointing to each script array contained in the script source file,

followed by offset values that point to locations within each script array

containing data references that must be patched.

During the Firmware initialization, the siop_init() function walks this

relocation table and patches all locations pointed to by this table to adjust for

the base address of the dynamically allocated siopdata.

Execution of the SCRIPTS preprocessor is required only when the SCRIPTS

source code is recompiled. However, the patching of the SCRIPTS is

performed on each call to siop_init(). Multiple calls to siop_init() perform this

relocation independently of any relocations performed on previous calls to

siop_init().