Intel 64 and IA-32 Architectures Software Developers Manual Volume 2B, Instruction Set Reference, N-Z

A-30 Vol. 2B
OPCODE MAP
A.5.2.8 Escape Opcodes with DF As First Byte
Table A-21 and A-22 contain the opcode maps for escape instruction opcodes that
begin with DFH. Table A-21 shows the opcode map if the ModR/M byte is in the range
of 00H-BFH. Here, the value of bits 3-5 (the nnn field in Figure A-1) selects the
instruction.
Table A-22 shows the opcode map if the ModR/M byte is outside the range of
00H-BFH. The first digit of the ModR/M byte selects the table row and the second
digit selects the column.
Table A-21. DF Opcode Map When ModR/M Byte is Within 00H to BFH *
nnn Field of ModR/M Byte
000B 001B 010B 011B 100B 101B 110B 111B
FILD
word-integer
FISTTP
word-integer
FIST
word-integer
FISTP
word-integer
FBLD packed-
BCD
FILD
qword-integer
FBSTP packed-
BCD
FISTP
qword-integer
NOTES:
*
All blanks in all opcode maps are reserved and must not be used. Do not depend on the operation of unde-
fined or reserved locations.
Table A-22. DF Opcode Map When ModR/M Byte is Outside 00H to BFH
*
0 123456 7
C
D
E FSTSW
AX
FFCOMIP
ST(0),ST(0) ST(0),ST(1) ST(0),ST(2) ST(0),ST(3) ST(0),ST(4) ST(0),ST(5) ST(0),ST(6) ST(0),ST(7)
89ABCDEF
C
D
E FUCOMIP
ST(0),ST(0) ST(0),ST(1) ST(0),ST(2) ST(0),ST(3) ST(0),ST(4) ST(0),ST(5) ST(0),ST(6) ST(0),ST(7)
F
NOTES:
*
All blanks in all opcode maps are reserved and must not be used. Do not depend on the operation of unde-
fined or reserved locations.