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/*
code "borrowed" from JPEG-5 config code
*/
#include <stdio.h>
int is_shifting_signed (arg)
long arg;
/* See whether right-shift on a long is signed or not. */
{
long res = arg >> 4;
if (res == -0x7F7E80CL) { /* expected result for signed shift */
return 1; /* right shift is signed */
}
/* see if unsigned-shift hack will fix it. */
/* we can't just test exact value since it depends on width of long... */
res |= (~0L) << (32-4);
if (res == -0x7F7E80CL) { /* expected result now? */
return 0; /* right shift is unsigned */
}
fprintf(stderr, "Right shift isn't acting as I expect it to.\n");
fprintf(stderr, "I fear the DCT software will not work at all.\n\n");
exit(1);
}
main()
{
if (is_shifting_signed(-0x7F7E80B1L)) {
printf("do not define RIGHT_SHIFT_IS_UNSIGNED\n");
}
else {
printf("define RIGHT_SHIFT_IS_UNSIGNED\n");
}
}
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