Intel i86W Manual page 215

INSTRUCTION FORMAT AND ENCODING
Core Escape Instructions
31 26
15
10
5
o
010011
reserved SRC1 reserved
OPCODE
240329i
Core Escape Opcodes
4 3
2
o
(reserved) 0 0 0 0 0
lock
Begin Interlocked Sequence 0
0
0 0 1
calli Indirect Subroutine Call
0 0 0 1 0
(reserved) 0
0 0
1
1
intovr Trap on Integer Overflow 0 0 1
0 0
(reserved) 0 0 1 0 1
(reserved) 0
0
1 1 0
unlock End Interlocked Sequence
0 0 1 1 1
(reserved)
0
1
x x x
(reserved) 1 0
x x x
(reserved) 1 1
x x x
B-5