arch/mips/math-emu/ieee754.c

   1 /* ieee754 floating point arithmetic
   2  * single and double precision
   3  *
   4  * BUGS
   5  * not much dp done
   6  * doesn't generate IEEE754_INEXACT
   7  *
   8  */
   9 /*
  10  * MIPS floating point support
  11  * Copyright (C) 1994-2000 Algorithmics Ltd.
  12  * http://www.algor.co.uk
  13  *
  14  * ########################################################################
  15  *
  16  *  This program is free software; you can distribute it and/or modify it
  17  *  under the terms of the GNU General Public License (Version 2) as
  18  *  published by the Free Software Foundation.
  19  *
  20  *  This program is distributed in the hope it will be useful, but WITHOUT
  21  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  22  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  23  *  for more details.
  24  *
  25  *  You should have received a copy of the GNU General Public License along
  26  *  with this program; if not, write to the Free Software Foundation, Inc.,
  27  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  28  *
  29  * ########################################################################
  30  */
  31
  32
  33 #include "ieee754int.h"
  34
  35 #define DP_EBIAS        1023
  36 #define DP_EMIN         (-1022)
  37 #define DP_EMAX         1023
  38
  39 #define SP_EBIAS        127
  40 #define SP_EMIN         (-126)
  41 #define SP_EMAX         127
  42
  43 /* indexed by class */
  44 const char *const ieee754_cname[] = {
  45         "Normal",
  46         "Zero",
  47         "Denormal",
  48         "Infinity",
  49         "QNaN",
  50         "SNaN",
  51 };
  52
  53 /* the control status register
  54 */
  55 struct ieee754_csr ieee754_csr;
  56
  57 /* special constants
  58 */
  59
  60
  61 #if (defined(BYTE_ORDER) && BYTE_ORDER == LITTLE_ENDIAN) || defined(__MIPSEL__)
  62 #define SPSTR(s,b,m) {m,b,s}
  63 #define DPSTR(s,b,mh,ml) {ml,mh,b,s}
  64 #endif
  65
  66 #ifdef __MIPSEB__
  67 #define SPSTR(s,b,m) {s,b,m}
  68 #define DPSTR(s,b,mh,ml) {s,b,mh,ml}
  69 #endif
  70
  71 const struct ieee754dp_konst __ieee754dp_spcvals[] = {
  72         DPSTR(0, DP_EMIN - 1 + DP_EBIAS, 0, 0), /* + zero   */
  73         DPSTR(1, DP_EMIN - 1 + DP_EBIAS, 0, 0), /* - zero   */
  74         DPSTR(0, DP_EBIAS, 0, 0),       /* + 1.0   */
  75         DPSTR(1, DP_EBIAS, 0, 0),       /* - 1.0   */
  76         DPSTR(0, 3 + DP_EBIAS, 0x40000, 0),     /* + 10.0   */
  77         DPSTR(1, 3 + DP_EBIAS, 0x40000, 0),     /* - 10.0   */
  78         DPSTR(0, DP_EMAX + 1 + DP_EBIAS, 0, 0), /* + infinity */
  79         DPSTR(1, DP_EMAX + 1 + DP_EBIAS, 0, 0), /* - infinity */
  80         DPSTR(0,DP_EMAX+1+DP_EBIAS,0x7FFFF,0xFFFFFFFF), /* + indef quiet Nan */
  81         DPSTR(0, DP_EMAX + DP_EBIAS, 0xFFFFF, 0xFFFFFFFF),      /* + max */
  82         DPSTR(1, DP_EMAX + DP_EBIAS, 0xFFFFF, 0xFFFFFFFF),      /* - max */
  83         DPSTR(0, DP_EMIN + DP_EBIAS, 0, 0),     /* + min normal */
  84         DPSTR(1, DP_EMIN + DP_EBIAS, 0, 0),     /* - min normal */
  85         DPSTR(0, DP_EMIN - 1 + DP_EBIAS, 0, 1), /* + min denormal */
  86         DPSTR(1, DP_EMIN - 1 + DP_EBIAS, 0, 1), /* - min denormal */
  87         DPSTR(0, 31 + DP_EBIAS, 0, 0),  /* + 1.0e31 */
  88         DPSTR(0, 63 + DP_EBIAS, 0, 0),  /* + 1.0e63 */
  89 };
  90
  91 const struct ieee754sp_konst __ieee754sp_spcvals[] = {
  92         SPSTR(0, SP_EMIN - 1 + SP_EBIAS, 0),    /* + zero   */
  93         SPSTR(1, SP_EMIN - 1 + SP_EBIAS, 0),    /* - zero   */
  94         SPSTR(0, SP_EBIAS, 0),  /* + 1.0   */
  95         SPSTR(1, SP_EBIAS, 0),  /* - 1.0   */
  96         SPSTR(0, 3 + SP_EBIAS, 0x200000),       /* + 10.0   */
  97         SPSTR(1, 3 + SP_EBIAS, 0x200000),       /* - 10.0   */
  98         SPSTR(0, SP_EMAX + 1 + SP_EBIAS, 0),    /* + infinity */
  99         SPSTR(1, SP_EMAX + 1 + SP_EBIAS, 0),    /* - infinity */
 100         SPSTR(0,SP_EMAX+1+SP_EBIAS,0x3FFFFF),     /* + indef quiet Nan  */
 101         SPSTR(0, SP_EMAX + SP_EBIAS, 0x7FFFFF), /* + max normal */
 102         SPSTR(1, SP_EMAX + SP_EBIAS, 0x7FFFFF), /* - max normal */
 103         SPSTR(0, SP_EMIN + SP_EBIAS, 0),        /* + min normal */
 104         SPSTR(1, SP_EMIN + SP_EBIAS, 0),        /* - min normal */
 105         SPSTR(0, SP_EMIN - 1 + SP_EBIAS, 1),    /* + min denormal */
 106         SPSTR(1, SP_EMIN - 1 + SP_EBIAS, 1),    /* - min denormal */
 107         SPSTR(0, 31 + SP_EBIAS, 0),     /* + 1.0e31 */
 108         SPSTR(0, 63 + SP_EBIAS, 0),     /* + 1.0e63 */
 109 };
 110
 111
 112 int ieee754si_xcpt(int r, const char *op, ...)
 113 {
 114         struct ieee754xctx ax;
 115
 116         if (!TSTX())
 117                 return r;
 118         ax.op = op;
 119         ax.rt = IEEE754_RT_SI;
 120         ax.rv.si = r;
 121         va_start(ax.ap, op);
 122         ieee754_xcpt(&ax);
 123         return ax.rv.si;
 124 }
 125
 126 s64 ieee754di_xcpt(s64 r, const char *op, ...)
 127 {
 128         struct ieee754xctx ax;
 129
 130         if (!TSTX())
 131                 return r;
 132         ax.op = op;
 133         ax.rt = IEEE754_RT_DI;
 134         ax.rv.di = r;
 135         va_start(ax.ap, op);
 136         ieee754_xcpt(&ax);
 137         return ax.rv.di;
 138 }