Annotation of nono/fpe/fpu_hyperb.c, revision 1.1.1.1

1.1       root        1: /*     $NetBSD: fpu_hyperb.c,v 1.17 2016/12/05 15:31:01 isaki Exp $    */
                      2: 
                      3: /*
                      4:  * Copyright (c) 1995  Ken Nakata
                      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. Neither the name of the author nor the names of its contributors
                     16:  *    may be used to endorse or promote products derived from this software
                     17:  *    without specific prior written permission.
                     18:  *
                     19:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
                     20:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     21:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     22:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
                     23:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     24:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     25:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     26:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     27:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     28:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     29:  * SUCH DAMAGE.
                     30:  *
                     31:  *     @(#)fpu_hyperb.c        10/24/95
                     32:  */
                     33: 
                     34: /*
                     35:  * Copyright (c) 2011 Tetsuya Isaki. All rights reserved.
                     36:  *
                     37:  * Redistribution and use in source and binary forms, with or without
                     38:  * modification, are permitted provided that the following conditions
                     39:  * are met:
                     40:  * 1. Redistributions of source code must retain the above copyright
                     41:  *    notice, this list of conditions and the following disclaimer.
                     42:  * 2. Redistributions in binary form must reproduce the above copyright
                     43:  *    notice, this list of conditions and the following disclaimer in the
                     44:  *    documentation and/or other materials provided with the distribution.
                     45:  *
                     46:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
                     47:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
                     48:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
                     49:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
                     50:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
                     51:  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
                     52:  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
                     53:  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
                     54:  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     55:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     56:  * SUCH DAMAGE.
                     57:  */
                     58: 
                     59: #include "fpu_emulate.h"
                     60: 
                     61: /*
                     62:  * fpu_hyperb.c: defines the following functions
                     63:  *
                     64:  *     fpu_atanh(), fpu_cosh(), fpu_sinh(), and fpu_tanh()
                     65:  */
                     66: 
                     67: /*
                     68:  *             1       1 + x
                     69:  * atanh(x) = ---*log(-------)
                     70:  *             2       1 - x
                     71:  */
                     72: struct fpn *
                     73: fpu_atanh(struct fpemu *fe)
                     74: {
                     75:        struct fpn x;
                     76:        struct fpn t;
                     77:        struct fpn *r;
                     78: 
                     79:        if (ISNAN(&fe->fe_f2))
                     80:                return &fe->fe_f2;
                     81:        if (ISINF(&fe->fe_f2))
                     82:                return fpu_newnan(fe);
                     83: 
                     84:        /* if x is +0/-0, return +0/-0 */
                     85:        if (ISZERO(&fe->fe_f2))
                     86:                return &fe->fe_f2;
                     87: 
                     88:        /*
                     89:         * -INF if x == -1
                     90:         * +INF if x ==  1
                     91:         */
                     92:        r = &fe->fe_f2;
                     93:        if (r->fp_exp == 0 && r->fp_mant[0] == FP_1 &&
                     94:            r->fp_mant[1] == 0 && r->fp_mant[2] == 0) {
                     95:                r->fp_class = FPC_INF;
                     96:                return r;
                     97:        }
                     98: 
                     99:        /* NAN if |x| > 1 */
                    100:        if (fe->fe_f2.fp_exp >= 0)
                    101:                return fpu_newnan(fe);
                    102: 
                    103:        CPYFPN(&x, &fe->fe_f2);
                    104: 
                    105:        /* t := 1 - x */
                    106:        fpu_const(&fe->fe_f1, FPU_CONST_1);
                    107:        fe->fe_f2.fp_sign = !fe->fe_f2.fp_sign;
                    108:        r = fpu_add(fe);
                    109:        CPYFPN(&t, r);
                    110: 
                    111:        /* r := 1 + x */
                    112:        fpu_const(&fe->fe_f1, FPU_CONST_1);
                    113:        CPYFPN(&fe->fe_f2, &x);
                    114:        r = fpu_add(fe);
                    115: 
                    116:        /* (1-x)/(1+x) */
                    117:        CPYFPN(&fe->fe_f1, r);
                    118:        CPYFPN(&fe->fe_f2, &t);
                    119:        r = fpu_div(fe);
                    120: 
                    121:        /* log((1-x)/(1+x)) */
                    122:        CPYFPN(&fe->fe_f2, r);
                    123:        r = fpu_logn(fe);
                    124: 
                    125:        /* r /= 2 */
                    126:        r->fp_exp--;
                    127: 
                    128:        return r;
                    129: }
                    130: 
                    131: /*
                    132:  *            exp(x) + exp(-x)
                    133:  * cosh(x) = ------------------
                    134:  *                   2
                    135:  */
                    136: struct fpn *
                    137: fpu_cosh(struct fpemu *fe)
                    138: {
                    139:        struct fpn x, *fp;
                    140: 
                    141:        if (ISNAN(&fe->fe_f2))
                    142:                return &fe->fe_f2;
                    143: 
                    144:        if (ISINF(&fe->fe_f2)) {
                    145:                fe->fe_f2.fp_sign = 0;
                    146:                return &fe->fe_f2;
                    147:        }
                    148: 
                    149:        fp = fpu_etox(fe);
                    150:        CPYFPN(&x, fp);
                    151: 
                    152:        fpu_const(&fe->fe_f1, FPU_CONST_1);
                    153:        CPYFPN(&fe->fe_f2, fp);
                    154:        fp = fpu_div(fe);
                    155: 
                    156:        CPYFPN(&fe->fe_f1, fp);
                    157:        CPYFPN(&fe->fe_f2, &x);
                    158:        fp = fpu_add(fe);
                    159: 
                    160:        fp->fp_exp--;
                    161: 
                    162:        return fp;
                    163: }
                    164: 
                    165: /*
                    166:  *            exp(x) - exp(-x)
                    167:  * sinh(x) = ------------------
                    168:  *                   2
                    169:  */
                    170: struct fpn *
                    171: fpu_sinh(struct fpemu *fe)
                    172: {
                    173:        struct fpn x, *fp;
                    174: 
                    175:        if (ISNAN(&fe->fe_f2))
                    176:                return &fe->fe_f2;
                    177:        if (ISINF(&fe->fe_f2))
                    178:                return &fe->fe_f2;
                    179: 
                    180:        /* if x is +0/-0, return +0/-0 */
                    181:        if (ISZERO(&fe->fe_f2))
                    182:                return &fe->fe_f2;
                    183: 
                    184:        fp = fpu_etox(fe);
                    185:        CPYFPN(&x, fp);
                    186: 
                    187:        fpu_const(&fe->fe_f1, FPU_CONST_1);
                    188:        CPYFPN(&fe->fe_f2, fp);
                    189:        fp = fpu_div(fe);
                    190: 
                    191:        fp->fp_sign = 1;
                    192:        CPYFPN(&fe->fe_f1, fp);
                    193:        CPYFPN(&fe->fe_f2, &x);
                    194:        fp = fpu_add(fe);
                    195: 
                    196:        fp->fp_exp--;
                    197: 
                    198:        return fp;
                    199: }
                    200: 
                    201: /*
                    202:  *            sinh(x)
                    203:  * tanh(x) = ---------
                    204:  *            cosh(x)
                    205:  */
                    206: struct fpn *
                    207: fpu_tanh(struct fpemu *fe)
                    208: {
                    209:        struct fpn x;
                    210:        struct fpn s;
                    211:        struct fpn *r;
                    212:        struct fpn epx;
                    213:        struct fpn emx;
                    214: 
                    215:        if (ISNAN(&fe->fe_f2))
                    216:                return &fe->fe_f2;
                    217: 
                    218:        /* if x is +0/-0, return +0/-0 */
                    219:        if (ISZERO(&fe->fe_f2))
                    220:                return &fe->fe_f2;
                    221: 
                    222:        CPYFPN(&x, &fe->fe_f2);
                    223: 
                    224:        if (ISINF(&fe->fe_f2)) {
                    225:                fpu_const(&fe->fe_f2, FPU_CONST_1);
                    226:                fe->fe_f2.fp_sign = x.fp_sign;
                    227:                return &fe->fe_f2;
                    228:        }
                    229:        if (fe->fe_f2.fp_exp >= 8) {
                    230:                fpu_const(&fe->fe_f2, FPU_CONST_1);
                    231:                fe->fe_f2.fp_sign = x.fp_sign;
                    232:                fe->fe_fpsr |= FPSR_INEX2;      /* inexact */
                    233:                return &fe->fe_f2;
                    234:        }
                    235: 
                    236:        /* exp(x) */
                    237:        CPYFPN(&fe->fe_f2, &x);
                    238:        r = fpu_etox(fe);
                    239:        CPYFPN(&epx, r);
                    240: 
                    241:        /* exp(-x) */
                    242:        CPYFPN(&fe->fe_f2, &epx);
                    243:        fpu_const(&fe->fe_f1, FPU_CONST_1);
                    244:        r = fpu_div(fe);
                    245:        CPYFPN(&emx, r);
                    246: 
                    247:        /* exp(x) - exp(-x) */
                    248:        CPYFPN(&fe->fe_f1, &epx);
                    249:        CPYFPN(&fe->fe_f2, &emx);
                    250:        fe->fe_f2.fp_sign = !fe->fe_f2.fp_sign;
                    251:        r = fpu_add(fe);
                    252:        CPYFPN(&s, r);
                    253: 
                    254:        /* exp(x) + exp(-x) */
                    255:        CPYFPN(&fe->fe_f1, &epx);
                    256:        CPYFPN(&fe->fe_f2, &emx);
                    257:        r = fpu_add(fe);
                    258: 
                    259:        CPYFPN(&fe->fe_f2, r);
                    260:        CPYFPN(&fe->fe_f1, &s);
                    261:        r = fpu_div(fe);
                    262: 
                    263:        return r;
                    264: }

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