Table of Contents
Advertisement
INTRODUCTION
•
Part II - System Implementation (chapters 11-17) identifies requirements for designing a system
around the i960 Jx components, such as external bus interface and interrupt controller. Also
described are programming requirements for the bus controller and processor initialization.
•
Part III - Appendices includes quick references for hardware design and programming.
Appendices are also provided which describe the internal architecture, how to write
assembly-level code to exploit the parallelism of the processor and considerations for writing
software that is portable among all members of the i960 microprocessor family.
1.3
NOTATION AND TERMINOLOGY
This section defines terminology and textual conventions that are used throughout the manual.
1.3.1
Reserved and Preserved
Certain fields in registers and data structures are described as being either reserved or preserved:
•
A reserved field is one that may be used by other i960 architecture implementations. Correct
treatment of reserved fields ensures software compatibility with other i960 processors. The
processor uses these fields for temporary storage; as a result, the fields sometimes contain
unusual values.
•
A preserved field is one that the processor does not use. Software may use preserved fields for
any function.
Reserved fields in certain data structures should be cleared (set to zero) when the data structure is
created. Clear the reserved fields when creating the Interrupt Table, Fault Table and System
Procedure Table. Software should not modify or rely on these reserved field values after a data
structure is created. When the processor creates the Interrupt or Fault Record data structure on the
stack, software should not depend on the value of the reserved fields within these data structures.
Some bits or fields in data structures and registers are shown as requiring specific encoding. These
fields should be treated as if they were reserved fields. They should be set to the specified value
when the data structure is created or when the register is initialized and software should not
modify or rely on the value after that.
Reserved bits in the Arithmetic Controls (AC) register can be cleared after initialization to ensure
compatibility with other i960 processor implementations. Reserved bits in the Process Controls
(PC) register and Trace Controls (TC) register should not be initialized. When the AC, PC and TC
registers are modified using
registers must be masked.
1-8
,
or
instructions, the reserved locations in these
modac
modpc
modtc
Advertisement
Table of Contents
