remainderl.c revision ddc0e0b53c661f6e439e3b7072b3ef353eadb4af
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25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Use is subject to license terms.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * remainderl(x,p)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * returns x REM p = x - [x/p]*p as if in infinite
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * precise arithmetic, where [x/p] is the (inifinite bit)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * integer nearest x/p (in half way case choose the even one).
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Based on fmodl() return x-[x/p]chopped*p exactly.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define HFMAX 5.948657476786158825428796633140035080982e+4931L
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define DBMIN 6.724206286224187012525355634643505205196e-4932L
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisstatic const long double
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis hfmax = HFMAX, /* half of the maximum number */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis dbmin = DBMIN; /* double of the minimum (normal) number */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisremainderl(long double x, long double p) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return (x + p);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return (x - x);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis x = fmodl(x, p + p);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (x + x > p) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis x -= p; /* avoid x-x=-0 in RM mode */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (x + x >= p)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis x -= p; /* avoid x-x=-0 in RM mode */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return (sx == 0 ? x : -x);