lib/libc/arch/powerpc/gen/flt_rounds.c

   1 /*      $NetBSD: flt_rounds.c,v 1.11 2011/07/10 21:18:47 matt Exp $     */
   2
   3 /*
   4  * Copyright (c) 1996 Mark Brinicombe
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *      This product includes software developed by Mark Brinicombe
  18  *      for the NetBSD Project.
  19  * 4. The name of the author may not be used to endorse or promote products
  20  *    derived from this software without specific prior written permission
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 #include <sys/cdefs.h>
  35 #if defined(LIBC_SCCS) && !defined(lint)
  36 __RCSID("$NetBSD: flt_rounds.c,v 1.11 2011/07/10 21:18:47 matt Exp $");
  37 #endif /* LIBC_SCCS and not lint */
  38
  39 #include <ieeefp.h>
  40 #include <float.h>
  41 #include <stdint.h>
  42 #include <powerpc/fpu.h>
  43
  44 static const int map[] = {
  45         1,      /* round to nearest */
  46         0,      /* round to zero */
  47         2,      /* round to positive infinity */
  48         3       /* round to negative infinity */
  49 };
  50
  51 int
  52 __flt_rounds(void)
  53 {
  54 #ifdef _SOFT_FLOAT
  55         return map[fpgetround()];
  56 #else
  57         union {
  58                 double u_d;
  59                 uint64_t u_fpscr;
  60         } ud;
  61
  62         __asm volatile("mffs %0" : "=f"(ud.u_d));
  63         return map[((uint32_t)ud.u_fpscr & FPSCR_RN)];
  64 #endif
  65 }