[BSWAP with 16-bit registers]                         [Assembler][/][80486]

BSWAP with a word register operand is a valid instruction. At least in the
Genuine Intel processors. Some specifications recommend againsts usingit
for better compatibility with Intel-clones. The instruction brings down the
upper word of the doubleword register without affecting its upper 16 bits.
For example, if EAX = AB120000h then:

        bswap   ax

results in EAX = AB1212ABh. Flags will not be affected.
                                                     Gem writer: Ervin Toth
                                                   last updated: 1998-03-16
