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Instruction mmx - PSUBB/PSUBW/PSUBD—Packed Subtract

Subtracts the individual data elements (bytes, words, or doublewords) of the source operand (second operand) from the individual data elements of the destination operand (first operand). If the result of a subtraction exceeds the range for the specified data type (overflows), the result is wrapped around, meaning that the result is truncated so that only the lower (least significant) bits of the result are returned (that is, the carry is ignored). The destination operand must be an MMX technology register; the source operand can be either an MMX technology register or a quadword memory location.