FXCH

X87_ALU X87 x86_64

4 encoding forms.

X86_FXCH_X86_LEGACY_ONEBYTE_D9_0
(no syntax)
X86_LEGACY D9 FPU
X86_FXCH_X86_LEGACY_ONEBYTE_D9_10310
st(i)
X86_LEGACY D9 FPU
XED_FXCH_ST0_X87_DFC1 FXCH_ST0_X87_DDC1
REG0=XED_REG_ST0:rw:IMPL:f80 REG1=X87():rw:f80 REG2=XED_REG_X87STATUS:w:SUPP REG0=XED_REG_ST0:rw:IMPL:f80 REG1=X87():rw:f80 REG2=XED_REG_X87STATUS:w:SUPP
X86_LEGACY DF DD /1 X87
XED_FXCH_X86_LEGACY_ONEBYTE_D9_714948
REG0=XED_REG_ST0:rw:IMPL:f80 REG1=X87():rw:f80 REG2=XED_REG_X87STATUS:w:SUPP
X86_LEGACY D9 /1 X87