Intel® Architecture Instruction Set Extensions Programming Reference

OPCODE MAP
Table A-18 shows the 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-18. DD Opcode Map When ModR/M Byte is Outside 00H to BFH *
0 1 2 3 4 5 6 7
C FFREE
ST(0) ST(1) ST(2) ST(3) ST(4) ST(5) ST(6) ST(7)
D FST
ST(0) ST(1) ST(2) ST(3) ST(4) ST(5) ST(6) ST(7)
E FUCOM
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),ST(0)
F
C
8 9 A B C D E F
D FSTP
ST(0) ST(1) ST(2) ST(3) ST(4) ST(5) ST(6) ST(7)
E FUCOMP
ST(0) ST(1) ST(2) ST(3) ST(4) ST(5) ST(6) ST(7)
F
NOTES:
* All blanks in all opcode maps are reserved and must not be used. Do not depend on the operation of undefined or reserved locations.
A.5.2.7 Escape Opcodes with DE as First Byte
Table A-19 and A-20 contain opcode maps for escape instruction opcodes that begin with DEH. Table A-19 shows the opcode map
if the ModR/M byte is in the range of 00H-BFH. In this case, the value of bits 3-5 (the nnn field in Figure A-1) selects the instruction.
Table A-19. DE 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
FIADD
FIMUL FICOM FICOMP FISUB FISUBR FIDIV
FIDIVR
word-integer
NOTES:
word-integer word-integer word-integer word-integer word-integer word-integer word-integer
* All blanks in all opcode maps are reserved and must not be used. Do not depend on the operation of undefined or reserved locations.
Ref. # 319433-014 A-27