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March 2002 Release
Virtex-II Pro™ Platform FPGA Documentation
1-800-255-7778
Branch Instructions
R
lists the simplified-mnemonic assembler syntax for the branch-conditional to LR
and branch-conditional to CTR instructions (true/false conditions) that do not update the
LR.
lists the simplified-mnemonic assembler syntax for the branch-conditional
relative and branch-conditional absolute instructions (true/false conditions) that update
the LR. In the following table,
target
represents the target address of the branch.
Table C-4:
Branch (True/False) to LR/CTR (LK=0)
Operation
LR not Updated
Branch to LR
Branch to CTR
Simplified
Mnemonic
Equivalent
Mnemonic
Simplified
Mnemonic
Equivalent
Mnemonic
Branch Unconditionally
blr
bclr
20, 0
bctr
bcctr
20, 0
Branch if Condition True (CR
b
=
1)
btlr
b
bclr
12,
b
btctr
b
bcctr
12,
b
Branch if Condition False (CR
b
=
0)
bflr
b
bclr
4,
b
bfctr
b
bcctr
4,
b
Decrement CTR,
Branch if CTR
≠
0
bdnzlr
bclr
16, 0
—
—
Decrement CTR,
Branch if CTR
≠
0 and Condition True (CR
b
=
1)
bdnztlr
b
bclr
8,
b
—
—
Decrement CTR,
Branch if CTR
≠
0 and Condition False (CR
b
=
0)
bdnzflr
b
bclr
0,
b
—
—
Decrement CTR,
Branch if CTR
=
0
bdzlr
bclr
18, 0
—
—
Decrement CTR,
Branch if CTR
=
0 and Condition True (CR
b
=
1)
bdztlr
b
bclr
10,
b
—
—
Decrement CTR,
Branch if CTR
=
0 and Condition False (CR
b
=
0)
bdzflr
b
bclr
2,
b
—
—
Table C-5:
Branch (True/False) to Relative/Absolute (LK=1)
Operation
LR Updated
Branch Relative
Branch Absolute
Simplified
Mnemonic
Equivalent
Mnemonic
Simplified
Mnemonic
Equivalent
Mnemonic
Branch Unconditionally
—
—
—
—
Branch if Condition True (CR
b
=
1)
btl
b
, target
bcl
12,
b
, target
btla
b
, target
bcla
12,
b
, target
Branch if Condition False (CR
b
=
0)
bfl
b
, target
bcl
4,
b
, target
bfla
b
, target
bcla
4,
b
, target
Decrement CTR,
Branch if CTR
≠
0
bdnzl
target
bcl
16, 0
, target
bdnzla
target
bcla
16, 0
, target
Decrement CTR,
Branch if CTR
≠
0 and Condition True (CR
b
=
1)
bdnztl
b
, target
bcl
8,
b
, target
bdnztla
b
, target
bcla
8,
b
, target
Decrement CTR,
Branch if CTR
≠
0 and Condition False (CR
b
=
0)
bdnzfl
b
, target
bcl
0,
b
, target
bdnzfla
b
, target
bcla
0,
b
, target
Decrement CTR,
Branch if CTR
=
0
bdzl
target
bcl
18, 0
, target
bdzla
target
bcla
18, 0
, target
Decrement CTR,
Branch if CTR
=
0 and Condition True (CR
b
=
1)
bdztl
b
, target
bcl
10,
b
, target
bdztla
b
, target
bcla
10,
b
, target