BM> The operand-size override prefix is 66h, and the address-size override 
pref
BM> is 67h.  These reverse 16/32 bit operands and addresses, respectively.  
In 
BM> Use16 segment, the default is 16 for both, and in a Use32 segment the 
defau
BM> is 32 bit operands/addresses.
BM> For 32-bit indirect memory operands, the r/m bits in most cases mean [reg 
{
BM> disp}], except for 100 which means a SIB is needed, and mod=00, r/m=101 
mea
BM> DS:disp32.  For the reg bits, the extended registers use the same codes 
s
BM> their subregisters would.
    You lost me on the Use16/32 segments. I don't know what signifies when
    to use the 16 bit encoding of the ModRegR/M byte, and when to use the
    32 bit encoding. I don't know what a Use16/32 segment is.
--- GEcho 1.00
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