
INSTRUCTION SET OVERVIEW
5-11
5
5.2.5
Bit, Bit Field and Byte Operations
These instructions perform operations on a specified bit or bit field in an ordinal operand. All Bit, Bit
Field and Byte instructions use the REG format and can operate on literals or local or global registers.
5.2.5.1
Bit Operations
These instructions operate on a specified bit:
•
setbit
,
clrbit
and
notbit
set, clear or complement (toggle) a specified bit in an ordinal.
•
alterbit
alters the state of a specified bit in an ordinal according to the condition code. When
the condition code is 010
2
, the bit is set; when the condition code is 000
2
, the bit is cleared.
•
chkbit
, described in
section 5.2.6, “Comparison” (pg. 5-12)
, can be used to check the value of
an individual bit in an ordinal.
•
scanbit
and
spanbit
find the most significant set bit or clear bit, respectively, in an ordinal.
5.2.5.2
Bit Field Operations
The two bit field instructions are
extract
and
modify
.
•
extract
converts a specified bit field, taken from an ordinal value, into an ordinal value. In
essence, this instruction shifts right a bit field in a register and fills in the bits to the left of the
bit field with zeros. (
eshro
also provides the equivalent of a 64-bit extract of 32 bits).
•
modify
copies bits from one register into another register. Only masked bits in the destination
register are modified.
modify
is equivalent to a bit field move.
5.2.5.3
Byte Operations
•
scanbyte
performs a byte-by-byte comparison of two ordinals to determine when any two
corresponding bytes are equal. The condition code is set based on the results of the
comparison.
scanbyte
uses the REG format and can specify literals or local or global registers
as arguments.
•
bswap
alters the order of bytes in a word, reversing its “endianess.” For more information on
this subject, see
section 13.6.2, “Selecting the Byte Order” (pg. 13-12)
.
setbit
set bit
clrbit
clear bit
notbit
invert bit
alterbit
alter bit
scanbit
scan for bit
spanbit
span over bit
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 ...
Page 48: ......
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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