
Glossary-1
GL
OS
S
A
R
Y
GLOSSARY
Address Space
An array of bytes used to store program code, data, stacks and system
data structures required to execute a program. Address space is linear –
also called flat – and byte addressable, with addresses running contigu-
ously from 0 to 2
32
- 1. It can be mapped to read-write memory, read-only
memory and memory-mapped I/O. i960
®
architecture does not define a
dedicated, addressable I/O space.
Address
A 32-bit value in the range 0 to FFFF FFFFH used to reference in
memory a single byte, half-word (2 bytes), word (4 bytes), double-word
(8 bytes), triple-word (12 bytes) or quad-word (16 bytes). Choice depends
on the instruction used.
Arithmetic
Controls (AC)
Register
A 32-bit register that contains flags and masks used in controlling the
various arithmetic and comparison operations that the processor
performs. Flags and masks contained in this register include the condition
code flags, integer-overflow flag and mask bit and the no-imprecise-faults
(NIF) bit. All unused bits in this register are reserved and must be set to 0.
Asynchronous
Faults
Faults that occur with no direct relationship to a particular instruction in the
instruction stream. When an asynchronous fault occurs, the address of the
faulting instruction in the fault record and the saved IP are undefined. i960
core architecture does not define any fault types that are asynchronous.
Big Endian
The bus controller reads or writes a data word’s least-significant byte to
the bus’ eight most-significant data lines (D31:24). Big endian systems
store the least-significant byte at the highest byte address in memory. So,
if a big endian ordered word is stored at address 600, the least-significant
byte is stored at address 603 and the most-significant byte at address 600.
Compare with little endian.
Condition Code
Flags
AC register bits 0, 1 and 2. The condition code flags indicate the results of
certain instructions – usually compare instructions. Other instructions,
such as conditional branch instructions, examine these flags and perform
functions according to their state. Once the processor sets the condition
code flags, they remain unchanged until the processor executes another
instruction that uses these flags to store results.
Execution Mode
Flag
PC register bit 1. This flag determines whether the processor is operating
in user mode (0) or supervisor mode (1).
Fault Call
An implicit call to a fault handling procedure. The processor performs
fault calls automatically without any intervention from software. It gets
pointers to fault handling procedures from the fault table.
Summary of Contents for i960 Jx
Page 1: ...Release Date December 1997 Order Number 272483 002 i960 Jx Microprocessor Developer s Manual ...
Page 24: ......
Page 25: ...1 INTRODUCTION ...
Page 26: ......
Page 35: ...2 DATA TYPES AND MEMORY ADDRESSING MODES ...
Page 36: ......
Page 46: ......
Page 47: ...3 PROGRAMMING ENVIRONMENT ...
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Page 73: ...4 CACHE AND ON CHIP DATA RAM ...
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Page 85: ...5 INSTRUCTION SET OVERVIEW ...
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Page 111: ...6 INSTRUCTION SET REFERENCE ...
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Page 233: ...7 PROCEDURE CALLS ...
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Page 257: ...8 FAULTS ...
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Page 291: ...9 TRACING AND DEBUGGING ...
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Page 309: ...10 TIMERS ...
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Page 325: ...11 INTERRUPTS ...
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Page 369: ...12 INITIALIZATION AND SYSTEM REQUIREMENTS ...
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Page 413: ...13 MEMORY CONFIGURATION ...
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Page 429: ...14 EXTERNAL BUS ...
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Page 469: ...15 TEST FEATURES ...
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Page 493: ...A CONSIDERATIONS FOR WRITING PORTABLE CODE ...
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Page 503: ...B OPCODES AND EXECUTION TIMES ...
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Page 515: ...C MACHINE LEVEL INSTRUCTION FORMATS ...
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Page 523: ...D REGISTER AND DATA STRUCTURES ...
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Page 551: ...GLOSSARY ...
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Page 561: ...INDEX ...
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