/* Duff's device is legal C; test to make sure the compiler
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/* Duff's device is legal C; test to make sure the compiler
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doesn't complain about it.
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doesn't complain about it.
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Jason Thorpe <thorpej@wasabisystems.com>
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Jason Thorpe <thorpej@wasabisystems.com>
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Derived from Tom Duff's original usenet message about the device. */
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Derived from Tom Duff's original usenet message about the device. */
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/* { dg-do run } */
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/* { dg-do run } */
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/* { dg-options "-O2" } */
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/* { dg-options "-O2" } */
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extern void abort (void);
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extern void abort (void);
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extern void exit (int);
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extern void exit (int);
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typedef __SIZE_TYPE__ size_t;
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typedef __SIZE_TYPE__ size_t;
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extern int memcmp (const void *, const void *, size_t);
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extern int memcmp (const void *, const void *, size_t);
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void
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void
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duffcpy (char *dst, const char *src, unsigned long size)
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duffcpy (char *dst, const char *src, unsigned long size)
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{
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{
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unsigned long n = (size + 7) / 8;
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unsigned long n = (size + 7) / 8;
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switch (size % 8)
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switch (size % 8)
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{
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{
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case 0: do { *dst++ = *src++;
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case 0: do { *dst++ = *src++;
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case 7: *dst++ = *src++;
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case 7: *dst++ = *src++;
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case 6: *dst++ = *src++;
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case 6: *dst++ = *src++;
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case 5: *dst++ = *src++;
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case 5: *dst++ = *src++;
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case 4: *dst++ = *src++;
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case 4: *dst++ = *src++;
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case 3: *dst++ = *src++;
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case 3: *dst++ = *src++;
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case 2: *dst++ = *src++;
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case 2: *dst++ = *src++;
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case 1: *dst++ = *src++;
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case 1: *dst++ = *src++;
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} while (--n > 0);
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} while (--n > 0);
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}
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}
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}
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}
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const char testpat[] = "The quick brown fox jumped over the lazy dog.";
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const char testpat[] = "The quick brown fox jumped over the lazy dog.";
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int
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int
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main()
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main()
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{
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{
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char buf[64];
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char buf[64];
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duffcpy (buf, testpat, sizeof (testpat));
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duffcpy (buf, testpat, sizeof (testpat));
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if (memcmp (buf, testpat, sizeof (testpat)) != 0)
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if (memcmp (buf, testpat, sizeof (testpat)) != 0)
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abort ();
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abort ();
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exit (0);
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exit (0);
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}
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}
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