FXAM

REG0=XED_REG_ST0:rw:SUPP:f80 REG1=XED_REG_X87STATUS:w:SUPP

x86_64 X86_LEGACY X87_ALU X87 source: xed

XED_FXAM_X86_LEGACY_ONEBYTE_D9_721787

Encoding

encoding_kindX86_LEGACY
opcode_bytesD9
opcode_mapONEBYTE
mandatory_prefix-
has_modrmTrue
modrm.reg = /4/4
attributesNOTSX
cpl3
raw_encoding0xD9 MOD[0b11] MOD=3 REG[0b100] RM[0b101]

Operands (2)

# Role Kind Class / Reg Width Access Visibility Encoded in
0 REG0 REG (=ST0) f80 RW SUPPRESSED MODRM_REG
1 REG1 REG w W SUPPRESSED MODRM_REG

Micro-ops sequence (0)

No micro-ops authored for this encoding. Emulator semantics not yet defined — decoder still works.