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3:20
Volume 3: Instruction Reference
br
br — Branch
Format:
(
qp
) br.
btype
.
bwh
.
ph
.
dh target
25
ip_relative_form
(
qp
) br.
btype
.
bwh
.
ph
.
dh b
1
=
target
25
call_form, ip_relative_form
br.
btype
.
bwh
.
ph
.
dh target
25
counted_form, ip_relative_form
br.
ph
.
dh target
25
pseudo-op
(
qp
) br.
btype
.
bwh
.
ph
.
dh b
2
indirect_form
(
qp
) br.
btype
.
bwh
.
ph
.
dh b
1
=
b
2
call_form, indirect_form
br.
ph
.
dh b
2
pseudo-op
Description:
A branch condition is evaluated, and either a branch is taken, or execution continues
with the next sequential instruction. The execution of a branch logically follows the
execution of all previous non-branch instructions in the same instruction group. On a
taken branch, execution begins at slot 0.
Branches can be either IP-relative, or indirect. For IP-relative branches, the
target
25
operand, in assembly, specifies a label to branch to. This is encoded in the branch
instruction as a signed immediate displacement (
imm
21
) between the target bundle and
the bundle containing this instruction (
imm
21
=
target
25
- IP >> 4). For indirect branches,
the target address is taken from BR
b
2
.
There are two pseudo-ops for unconditional branches. These are encoded like a
conditional branch (
btype
= cond), with the
qp
field specifying PR 0, and with the
bwh
hint of sptk.
The branch type determines how the branch condition is calculated and whether the
branch has other effects (such as writing a link register). For the basic branch types,
Table 2-6.
Branch Types
btype
Function
Branch Condition
Target Address
cond or
none
Conditional branch
Qualifying predicate
IP-rel or Indirect
call
Conditional procedure call
Qualifying predicate
IP-rel or Indirect
ret
Conditional procedure return
Qualifying predicate
Indirect
ia
Invoke IA-32 instruction set
Unconditional
Indirect
cloop
Counted loop branch
Loop count
IP-rel
ctop, cexit
Mod-scheduled counted loop
Loop count and epilog
count
IP-rel
wtop, wexit
Mod-scheduled while loop
Qualifying predicate and
epilog count
IP-rel
Содержание ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS VOLUME 3 REV 2.3
Страница 1: ......
Страница 11: ...x Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 12: ...1 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I Application Architecture Guide ...
Страница 13: ...1 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 33: ...1 22 Volume 1 Part 1 Introduction to the Intel Itanium Architecture ...
Страница 57: ...1 46 Volume 1 Part 1 Execution Environment ...
Страница 147: ...1 136 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 149: ...1 138 Volume 1 Part 2 About the Optimization Guide ...
Страница 191: ...1 180 Volume 1 Part 2 Predication Control Flow and Instruction Stream ...
Страница 230: ......
Страница 248: ...236 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 249: ...2 1 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part I System Architecture Guide ...
Страница 250: ...2 2 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 264: ...2 16 Volume 2 Part 1 Intel Itanium System Environment ...
Страница 380: ...2 132 Volume 2 Part 1 Interruptions ...
Страница 398: ...2 150 Volume 2 Part 1 Register Stack Engine ...
Страница 486: ...2 238 Volume 2 Part 1 IA 32 Interruption Vector Descriptions ...
Страница 749: ...2 501 Intel Itanium Architecture Software Developer s Manual Rev 2 3 Part II System Programmer s Guide ...
Страница 750: ...2 502 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 754: ...2 506 Volume 2 Part 2 About the System Programmer s Guide ...
Страница 796: ...2 548 Volume 2 Part 2 Interruptions and Serialization ...
Страница 808: ...2 560 Volume 2 Part 2 Context Management ...
Страница 842: ...2 594 Volume 2 Part 2 Floating point System Software ...
Страница 850: ...2 602 Volume 2 Part 2 IA 32 Application Support ...
Страница 862: ...2 614 Volume 2 Part 2 External Interrupt Architecture ...
Страница 870: ...2 622 Volume 2 Part 2 Performance Monitoring Support ...
Страница 891: ......
Страница 941: ...3 42 Volume 3 Instruction Reference cmp illegal_operation_fault PR p1 0 PR p2 0 Interruptions Illegal Operation fault ...
Страница 1099: ...3 200 Volume 3 Instruction Reference padd Interruptions Illegal Operation fault ...
Страница 1191: ...3 292 Volume 3 Pseudo Code Functions Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1295: ...3 396 Volume 3 Resource and Dependency Semantics ...
Страница 1296: ......
Страница 1302: ...402 Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1494: ...4 192 Volume 4 Base IA 32 Instruction Reference FWAIT Wait See entry for WAIT ...
Страница 1564: ...4 262 Volume 4 Base IA 32 Instruction Reference LES Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1565: ...Volume 4 Base IA 32 Instruction Reference 4 263 LFS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1568: ...4 266 Volume 4 Base IA 32 Instruction Reference LGS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1583: ...Volume 4 Base IA 32 Instruction Reference 4 281 LSS Load Full Pointer See entry for LDS LES LFS LGS LSS ...
Страница 1647: ...Volume 4 Base IA 32 Instruction Reference 4 345 ROL ROR Rotate See entry for RCL RCR ROL ROR ...
Страница 1663: ...Volume 4 Base IA 32 Instruction Reference 4 361 SHL SHR Shift Instructions See entry for SAL SAR SHL SHR ...
Страница 1668: ...4 366 Volume 4 Base IA 32 Instruction Reference SIDT Store Interrupt Descriptor Table Register See entry for SGDT SIDT ...
Страница 1884: ...4 582 Volume 4 IA 32 SSE Instruction Reference ...
Страница 1885: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 Index ...
Страница 1886: ...Index Intel Itanium Architecture Software Developer s Manual Rev 2 3 ...
Страница 1898: ...INDEX Index 12 Index for Volumes 1 2 3 and 4 ...