MACHINE-LEVEL INSTRUCTION FORMATS
C-5
C
The mode field determines the address mode used for the instruction.
Table C-6
summarizes the
addressing modes for the two MEM-format encodings. Fields used in these addressing modes are
described in the following sections.
C.5.1
MEMA Format Addressing
The MEMA format provides two addressing modes:
•
Absolute offset
•
Register indirect with offset
The offset field specifies an unsigned byte offset from 0 to 4096. The abase field specifies a global
or local register that contains an address in memory.
For the absolute-offset addressing mode (MODE = 00), the processor interprets the offset field as
an offset from byte 0 of the current process address space; the abase field is ignored. Using this
addressing mode along with the
lda
instruction allows a constant in the range 0 to 4096 to be
loaded into a register.
Table C-6. Addressing Modes for MEM Format Instructions
Format
MODE
Addressing Mode
Address Computation
# of Instr
Words
MEMA
00
Absolute Offset
offset
1
10
Register Indirect with Offset
(abase) + offset
1
MEMB
0100
Register Indirect
(abase)
1
0101
IP with Displacement
(IP) + displa 8
2
0110
Reserved
reserved
NA
0111
Register Indirect with Index
(abase) + (index) * 2
scale
1
1100
Absolute Displacement
displacement
2
1101
Register Indirect with
Displacement
(abase) + displacement
2
1110
Index with Displacement
(index) * 2
scale
+ displacement
2
1111
Register Indirect with Index and
Displacement
(abase) + (index) * 2
scale
+ displacement
2
NOTE
:
In these address computations, a field in parentheses indicates that the value in the specified regis-
ter is used in the computation.
Usage of a reserved encoding may cause generation of an OPERATION.INVALID_OPCODE
fault.
Содержание i960 Jx
Страница 1: ...Release Date December 1997 Order Number 272483 002 i960 Jx Microprocessor Developer s Manual ...
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Страница 25: ...1 INTRODUCTION ...
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Страница 35: ...2 DATA TYPES AND MEMORY ADDRESSING MODES ...
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Страница 47: ...3 PROGRAMMING ENVIRONMENT ...
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Страница 73: ...4 CACHE AND ON CHIP DATA RAM ...
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Страница 85: ...5 INSTRUCTION SET OVERVIEW ...
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Страница 111: ...6 INSTRUCTION SET REFERENCE ...
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Страница 195: ...INSTRUCTION SET REFERENCE 6 83 6 Opcode mov 5CCH REG movl 5DCH REG movt 5ECH REG movq 5FCH REG See Also LOAD STORE lda ...
Страница 233: ...7 PROCEDURE CALLS ...
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Страница 257: ...8 FAULTS ...
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Страница 291: ...9 TRACING AND DEBUGGING ...
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Страница 309: ...10 TIMERS ...
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Страница 325: ...11 INTERRUPTS ...
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Страница 369: ...12 INITIALIZATION AND SYSTEM REQUIREMENTS ...
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Страница 413: ...13 MEMORY CONFIGURATION ...
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Страница 429: ...14 EXTERNAL BUS ...
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Страница 469: ...15 TEST FEATURES ...
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Страница 493: ...A CONSIDERATIONS FOR WRITING PORTABLE CODE ...
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Страница 503: ...B OPCODES AND EXECUTION TIMES ...
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Страница 515: ...C MACHINE LEVEL INSTRUCTION FORMATS ...
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Страница 523: ...D REGISTER AND DATA STRUCTURES ...
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Страница 551: ...GLOSSARY ...
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Страница 561: ...INDEX ...
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