This opcode is shared with the Atom's MOVBE
instruction. I think this is how it looks for all combinations:
0F 38 F1 movbe My, Gy
66 0F 38 F1 movbe Mw, Gw
66 F2 0F 38 F1 crc32 Gd, Ew
F2 0F 38 F1 crc32 Gd, Ey
F2 66 0F 38 F1 crc32 Gd, Ew
EDIT: for most of opcodes in the 0F38 and 0F3A groups, the 66 prefix is a mandatory prefix which defines the actual instruction, and not the usual operand-size prefix:
Three-byte opcodes that are 4 bytes in length begin with a mandatory prefix (66H, F2H, or F3H) and two escape bytes (0F38H or 0F3AH). The upper and lower four bits of the fourth byte are used to index a particular row and column in Table A-4 or Table A-5.
That's why the case of the additional, optional 66 prefix used in its traditional role of operand-size override has to be listed separately.