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Synopsis:
    #include <mmintrin.h>
    __m64 _m_psubsb(__m64 *m1, __m64 *m2);

Description:
    The signed 8-bit bytes of m2 are subtracted from the respective signed
    8-bit bytes of m1 and the result is stored in memory.  Saturation occurs
    when a result exceeds the range of a signed byte.  In the case where a
    result is a byte larger than 0x7f (overflow), it is clamped to 0x7f.  In
    the case where a result is a byte smaller than 0x80 (underflow), it is
    clamped to 0x80.

Returns:
    The result of subtracting the packed signed bytes, with saturation, of
    one 64-bit multimedia value from a second multimedia value is returned.

Example:
    #include <stdio.h>
    #include <mmintrin.h>

    #define AS_BYTES "%2.2x %2.2x %2.2x %2.2x " \
                     "%2.2x %2.2x %2.2x %2.2x"

    __m64   a;
    __m64   b = { 0x8aacceef02244668 };
    __m64   c = { 0x76543211fedcba98 };

    void main()
      {
        a = _m_psubsb( b, c );
        printf( "m1="AS_BYTES"\n"
                "m2="AS_BYTES"\n"
                "mm="AS_BYTES"\n",
            b._8[7], b._8[6], b._8[5], b._8[4],
            b._8[3], b._8[2], b._8[1], b._8[0],
            c._8[7], c._8[6], c._8[5], c._8[4],
            c._8[3], c._8[2], c._8[1], c._8[0],
            a._8[7], a._8[6], a._8[5], a._8[4],
            a._8[3], a._8[2], a._8[1], a._8[0] );
      }

    produces the following:

    m1=8a ac ce ef 02 24 46 68
    m2=76 54 32 11 fe dc ba 98
    mm=80 80 9c de 04 48 7f 7f

Classification:
    Intel

Systems:
    MACRO

See Also:
    _m_empty, _m_psubb, _m_psubd, _m_psubsw, _m_psubusb, _m_psubusw,
    _m_psubw