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

Vol. 2B A-23

OPCODE MAP

A.5.2.1 Escape Opcodes with D8 as First Byte

Table A-7 and A-8 contain maps for the escape instruction opcodes that begin with

D8H. Table A-7 shows the 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-8 shows the map if the ModR/M byte is outside the range of 00H-BFH. Here,

the first digit of the ModR/M byte selects the table row and the second digit selects

the column.

Table A-7. D8 Opcode Map When ModR/M Byte is Within 00H to BFH *

nnn Field of ModR/M Byte (refer to Figure A.4)

000B 001B 010B 011B 100B 101B 110B 111B

FADD single-

real

FMUL single-

real

FCOM single-

real

FCOMP single-

real

FSUB single-

real

FSUBR single-

real

FDIV single-real FDIVR single-

real

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-8. D8 Opcode Map When ModR/M Byte is Outside 00H to BFH *

01234567

CFADD