1*61e56760Schristos /* $NetBSD: ulp.c,v 1.3 2011/03/20 23:15:35 christos Exp $ */
27684d5e0Skleink
37684d5e0Skleink /****************************************************************
47684d5e0Skleink
57684d5e0Skleink The author of this software is David M. Gay.
67684d5e0Skleink
77684d5e0Skleink Copyright (C) 1998, 1999 by Lucent Technologies
87684d5e0Skleink All Rights Reserved
97684d5e0Skleink
107684d5e0Skleink Permission to use, copy, modify, and distribute this software and
117684d5e0Skleink its documentation for any purpose and without fee is hereby
127684d5e0Skleink granted, provided that the above copyright notice appear in all
137684d5e0Skleink copies and that both that the copyright notice and this
147684d5e0Skleink permission notice and warranty disclaimer appear in supporting
157684d5e0Skleink documentation, and that the name of Lucent or any of its entities
167684d5e0Skleink not be used in advertising or publicity pertaining to
177684d5e0Skleink distribution of the software without specific, written prior
187684d5e0Skleink permission.
197684d5e0Skleink
207684d5e0Skleink LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
217684d5e0Skleink INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
227684d5e0Skleink IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
237684d5e0Skleink SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
247684d5e0Skleink WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
257684d5e0Skleink IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
267684d5e0Skleink ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
277684d5e0Skleink THIS SOFTWARE.
287684d5e0Skleink
297684d5e0Skleink ****************************************************************/
307684d5e0Skleink
317684d5e0Skleink /* Please send bug reports to David M. Gay (dmg at acm dot org,
327684d5e0Skleink * with " at " changed at "@" and " dot " changed to "."). */
337684d5e0Skleink
347684d5e0Skleink #include "gdtoaimp.h"
357684d5e0Skleink
367684d5e0Skleink double
ulp(x)377684d5e0Skleink ulp
387684d5e0Skleink #ifdef KR_headers
39*61e56760Schristos (x) U *x;
407684d5e0Skleink #else
41*61e56760Schristos (U *x)
427684d5e0Skleink #endif
437684d5e0Skleink {
447684d5e0Skleink Long L;
45*61e56760Schristos U a;
467684d5e0Skleink
477684d5e0Skleink L = (word0(x) & Exp_mask) - (P-1)*Exp_msk1;
487684d5e0Skleink #ifndef Sudden_Underflow
497684d5e0Skleink if (L > 0) {
507684d5e0Skleink #endif
517684d5e0Skleink #ifdef IBM
527684d5e0Skleink L |= Exp_msk1 >> 4;
537684d5e0Skleink #endif
54*61e56760Schristos word0(&a) = L;
55*61e56760Schristos word1(&a) = 0;
567684d5e0Skleink #ifndef Sudden_Underflow
577684d5e0Skleink }
587684d5e0Skleink else {
59ac898a26Skleink L = (unsigned int)-L >> Exp_shift;
607684d5e0Skleink if (L < Exp_shift) {
61*61e56760Schristos word0(&a) = 0x80000 >> L;
62*61e56760Schristos word1(&a) = 0;
637684d5e0Skleink }
647684d5e0Skleink else {
65*61e56760Schristos word0(&a) = 0;
667684d5e0Skleink L -= Exp_shift;
67*61e56760Schristos word1(&a) = L >= 31 ? 1 : 1 << (31 - L);
687684d5e0Skleink }
697684d5e0Skleink }
707684d5e0Skleink #endif
71*61e56760Schristos return dval(&a);
727684d5e0Skleink }
73