| 9 |
|
* |
| 10 |
|
* No interpolation in this version. |
| 11 |
|
* |
| 12 |
< |
* External symbols declared in standard.h |
| 12 |
> |
* External symbols declared in rtmath.h |
| 13 |
|
*/ |
| 14 |
|
|
| 15 |
|
#include "copyright.h" |
| 22 |
|
#define NCOSENTRY 256 |
| 23 |
|
#endif |
| 24 |
|
|
| 25 |
– |
#ifdef M_PI |
| 26 |
– |
#define PI ((double)M_PI) |
| 27 |
– |
#else |
| 28 |
– |
#define PI 3.14159265358979323846 |
| 29 |
– |
#endif |
| 25 |
|
|
| 31 |
– |
|
| 26 |
|
double |
| 27 |
< |
tcos(x) /* approximate cosine */ |
| 34 |
< |
register double x; |
| 27 |
> |
tcos(double x) /* approximate cosine */ |
| 28 |
|
{ |
| 29 |
|
static double costab[NCOSENTRY+1]; |
| 30 |
|
register int i; |
| 36 |
|
if (x < 0.) |
| 37 |
|
x = -x; |
| 38 |
|
i = (NCOSENTRY*2./PI) * x + 0.5; |
| 39 |
< |
if (i >= 4*NCOSENTRY) |
| 40 |
< |
i %= 4*NCOSENTRY; |
| 39 |
> |
while (i >= 4*NCOSENTRY) |
| 40 |
> |
i -= 4*NCOSENTRY; |
| 41 |
|
switch (i / NCOSENTRY) { |
| 42 |
|
case 0: |
| 43 |
|
return(costab[i]); |