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

Vol. 2B A-29

OPCODE MAP

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-20 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-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

word-integer

FIMUL

word-integer

FICOM

word-integer

FICOMP word-

integer

FISUB

word-integer

FISUBR word-

integer

FIDIV

word-integer

FIDIVR

word-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-20. DE Opcode Map When ModR/M Byte is Outside 00H to BFH *

0 123456 7

C FADDP