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/* Test of acos() function.
$Id: acos-01.c,v 1.1 2007/02/05 21:35:58 dmix Exp $
*/
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include "progmem.h"
union lofl_u {
long lo;
float fl;
};
volatile union lofl_u v = { .lo = 1 };
PROGMEM const struct { /* Table of test cases. */
union lofl_u x; /* argument */
union lofl_u z; /* acos(x) */
} t[] = {
/* Zero */
{ { .fl= +0.0 }, { 0x3fc90fdb } }, /* Pi/2 */
{ { .fl= -0.0 }, { 0x3fc90fdb } },
/* Subnormal */
{ { 0x00000001 }, { 0x3fc90fdb } },
{ { 0x00000100 }, { 0x3fc90fdb } },
{ { 0x00010000 }, { 0x3fc90fdb } },
{ { 0x007fffff }, { 0x3fc90fdb } },
{ { 0x80000001 }, { 0x3fc90fdb } },
{ { 0x80000100 }, { 0x3fc90fdb } },
{ { 0x80010000 }, { 0x3fc90fdb } },
{ { 0x807fffff }, { 0x3fc90fdb } },
/* Some values */
{ { .fl= 1.0 }, { .fl = 0.0 } },
{ { .fl= -1.0 }, { 0x40490fdb } }, /* Pi */
};
void x_exit (int index)
{
#ifndef __AVR__
fprintf (stderr, "t[%d]: %#lx\n", index - 1, v.lo);
#endif
exit (index ? index : -1);
}
static inline unsigned long distance (long a, long b)
{
unsigned long a1, b1;
a1 = (a < 0) ? (unsigned long)~a : a + 0x80000000;
b1 = (b < 0) ? (unsigned long)~b : b + 0x80000000;
return (a1 > b1) ? a1 - b1 : b1 - a1;
}
int main ()
{
union lofl_u x, z;
int i;
for (i = 0; i < (int) (sizeof(t) / sizeof(t[0])); i++) {
x.lo = pgm_read_dword (& t[i].x);
z.lo = pgm_read_dword (& t[i].z);
v.fl = acos (x.fl);
if (v.lo < 0 || distance(v.lo, z.lo) > 1)
x_exit (i+1);
}
return 0;
}
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