projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 683456d4 | 1 | /* |
| a7868ad7 RE |
2 | * Copyright (c) 1980 Regents of the University of California. |
| 3 | * All rights reserved. The Berkeley software License Agreement | |
| 4 | * specifies the terms and conditions for redistribution. | |
| 5 | * | |
| af857331 | 6 | * @(#)pow_ri.c 5.3 %G% |
| 683456d4 DW |
7 | */ |
| 8 | ||
| 9 | float pow_ri(ap, bp) | |
| 10 | float *ap; | |
| 11 | long int *bp; | |
| 12 | { | |
| 13 | double pow, x; | |
| 14 | long int n; | |
| 15 | ||
| 16 | pow = 1; | |
| 17 | x = *ap; | |
| 18 | n = *bp; | |
| 19 | ||
| 20 | if(n != 0) | |
| 21 | { | |
| 22 | if(n < 0) | |
| 23 | { | |
| 24 | if(x == 0) | |
| 25 | { | |
| af857331 | 26 | return(pow); |
| 683456d4 DW |
27 | } |
| 28 | n = -n; | |
| 29 | x = 1/x; | |
| 30 | } | |
| af857331 KM |
31 | if (x == 0) |
| 32 | return(0); | |
| 33 | ||
| 683456d4 DW |
34 | for( ; ; ) |
| 35 | { | |
| 36 | if(n & 01) | |
| 37 | pow *= x; | |
| 38 | if(n >>= 1) | |
| 39 | x *= x; | |
| 40 | else | |
| 41 | break; | |
| 42 | } | |
| 43 | } | |
| af857331 | 44 | return(pow); |
| 683456d4 | 45 | } |