mpcksswb.gml

开放源码的编译器open watcom 1.6.0版的源代码

.func _m_packsswb
#include <mmintrin.h>
__m64 _m_packsswb(__m64 *m1, __m64 *m2);
.funcend
.desc begin
Convert signed packed words into signed packed bytes by packing
(with signed saturation) the low-order bytes of the signed word
elements from
.arg m1
and
.arg m2
into the respective signed bytes of the result.
If the signed values in the word elements of
.arg m1
and
.arg m2
are smaller than 0x80, the result elements are clamped to 0x80.
If the signed values in the word elements of
.arg m1
and
.arg m2
are larger than 0x7f, the result elements are clamped to 0x7f.
.millust begin
            m2                         m1
-------------------------  -------------------------
|b7 b6|b5 b4|b3 b2|b1 b0|  |b7 b6|b5 b4|b3 b2|b1 b0|
-------------------------  -------------------------
   |     |     |     |        |     |     |     |
   |     |     |     `--.  .--'     |     |     |
   |     |     `-----.  |  |  .-----'     |     |
   |     `--------.  |  |  |  |  .--------'     |
   `-----------.  |  |  |  |  |  |  .-----------'
               |  |  |  |  |  |  |  |
               V  V  V  V  V  V  V  V
              -------------------------
              |b7|b6|b5|b4|b3|b2|b1|b0|
              -------------------------
                    result
.millust end
.desc end
.return begin
The result of packing, with signed saturation, 16-bit signed words
into 8-bit signed bytes is returned.
.return end
.see begin
.im seemmpck &function.
.see end
.exmp begin
#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"
#define AS_WORDS "%4.4x %4.4x %4.4x %4.4x"
#define AS_DWORDS "%8.8lx %8.8lx"
.exmp break
__m64   a;
__m64   b = { 0x0004000300020001 };
__m64   c = { 0xff7fff800080007f };
.exmp break
void main()
  {
    a = _m_packsswb( b, c );
    printf( "m2="AS_WORDS" "
            "m1="AS_WORDS"\n"
            "mm="AS_BYTES"\n",
        c._16[3], c._16[2], c._16[1], c._16[0],
        b._16[3], b._16[2], b._16[1], b._16[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] );
  }
.exmp output
m2=ff7f ff80 0080 007f m1=0004 0003 0002 0001
mm=80 80 7f 7f 04 03 02 01
.exmp end
.class Intel
.system