Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 1 REV 2.3 Manual page 1249

4.5.1 Branches
Opcode 0 is used for indirect branch, opcode 1 for indirect call, opcode 4 for IP-relative
branch, and opcode 5 for IP-relative call.
The IP-relative branch instructions encoded within major opcode 4 use a 3-bit opcode
extension field in bits 8:6 (btype) to distinguish the branch types as shown in
Table 4-47.
Table 4-47.
The indirect branch, indirect return, and miscellaneous branch-unit instructions are
encoded within major opcode 0 using a 6-bit opcode extension field in bits 32:27 (x
Table 4-48
Table 4-48.
Opcode
Bits 40:37
0
3:350
IP-Relative Branch Types
Opcode
Bits 40:37
4
summarizes these assignments.
Indirect/Miscellaneous Branch Opcode Extensions
Bits
30:27
0
0 break.b B9
1
2 cover B8
e
3
4 clrrrb B8
5 clrrrb.pr
e
6
e
7
8 rfi B8
9
e
A
e
B
C bsw.0 B8
D bsw.1 B8
e
E
e
F
btype
Bits 8:6
0
1
2
3
4
5
6
7
x
6
Bits 32:31
1
epc B8
e
e
e
e
e
B8
e
e
vmsw.0 B8
vmsw.1 B8
e
e
e
e
e
e
br.cond B1
e
br.wexit B1
br.wtop B1
e
br.cloop B2
br.cexit B2
br.ctop B2
2
Indirect Branch
(Table 4-49)
Indirect Return
(Table 4-50)
e
e
e
e
e
e
e
e
e
e
e
e
e
e
Volume 3: Instruction Formats
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