/* $OpenBSD: fpu_log.c,v 1.6 2006/06/11 20:43:28 miod Exp $ */
/* $NetBSD: fpu_log.c,v 1.8 2003/07/15 02:43:10 lukem Exp $ */
/*
* Copyright (c) 1995 Ken Nakata
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)fpu_log.c 10/8/95
*/
#include <sys/types.h>
#include <sys/systm.h>
#include <m68k/fpe/fpu_emulate.h>
static u_int logA6[] = { 0x3FC2499A, 0xB5E4040B };
static u_int logA5[] = { 0xBFC555B5, 0x848CB7DB };
static u_int logA4[] = { 0x3FC99999, 0x987D8730 };
static u_int logA3[] = { 0xBFCFFFFF, 0xFF6F7E97 };
static u_int logA2[] = { 0x3FD55555, 0x555555A4 };
static u_int logA1[] = { 0xBFE00000, 0x00000008 };
static u_int logB5[] = { 0x3F175496, 0xADD7DAD6 };
static u_int logB4[] = { 0x3F3C71C2, 0xFE80C7E0 };
static u_int logB3[] = { 0x3F624924, 0x928BCCFF };
static u_int logB2[] = { 0x3F899999, 0x999995EC };
static u_int logB1[] = { 0x3FB55555, 0x55555555 };
/* sfpn = shortened fp number; can represent only positive numbers */
static struct sfpn {
int sp_exp;
u_int sp_m0, sp_m1;
} logtbl[] = {
{ 0x3FFE - 0x3fff, 0xFE03F80FU, 0xE03F80FEU },
{ 0x3FF7 - 0x3fff, 0xFF015358U, 0x833C47E2U },
{ 0x3FFE - 0x3fff, 0xFA232CF2U, 0x52138AC0U },
{ 0x3FF9 - 0x3fff, 0xBDC8D83EU, 0xAD88D549U },
{ 0x3FFE - 0x3fff, 0xF6603D98U, 0x0F6603DAU },
{ 0x3FFA - 0x3fff, 0x9CF43DCFU, 0xF5EAFD48U },
{ 0x3FFE - 0x3fff, 0xF2B9D648U, 0x0F2B9D65U },
{ 0x3FFA - 0x3fff, 0xDA16EB88U, 0xCB8DF614U },
{ 0x3FFE - 0x3fff, 0xEF2EB71FU, 0xC4345238U },
{ 0x3FFB - 0x3fff, 0x8B29B775U, 0x1BD70743U },
{ 0x3FFE - 0x3fff, 0xEBBDB2A5U, 0xC1619C8CU },
{ 0x3FFB - 0x3fff, 0xA8D839F8U, 0x30C1FB49U },
{ 0x3FFE - 0x3fff, 0xE865AC7BU, 0x7603A197U },
{ 0x3FFB - 0x3fff, 0xC61A2EB1U, 0x8CD907ADU },
{ 0x3FFE - 0x3fff, 0xE525982AU, 0xF70C880EU },
{ 0x3FFB - 0x3fff, 0xE2F2A47AU, 0xDE3A18AFU },
{ 0x3FFE - 0x3fff, 0xE1FC780EU, 0x1FC780E2U },
{ 0x3FFB - 0x3fff, 0xFF64898EU, 0xDF55D551U },
{ 0x3FFE - 0x3fff, 0xDEE95C4CU, 0xA037BA57U },
{ 0x3FFC - 0x3fff, 0x8DB956A9U, 0x7B3D0148U },
{ 0x3FFE - 0x3fff, 0xDBEB61EEU, 0xD19C5958U },
{ 0x3FFC - 0x3fff, 0x9B8FE100U, 0xF47BA1DEU },
{ 0x3FFE - 0x3fff, 0xD901B203U, 0x6406C80EU },
{ 0x3FFC - 0x3fff, 0xA9372F1DU, 0x0DA1BD17U },
{ 0x3FFE - 0x3fff, 0xD62B80D6U, 0x2B80D62CU },
{ 0x3FFC - 0x3fff, 0xB6B07F38U, 0xCE90E46BU },
{ 0x3FFE - 0x3fff, 0xD3680D36U, 0x80D3680DU },
{ 0x3FFC - 0x3fff, 0xC3FD0329U, 0x06488481U },
{ 0x3FFE - 0x3fff, 0xD0B69FCBU, 0xD2580D0BU },
{ 0x3FFC - 0x3fff, 0xD11DE0FFU, 0x15AB18CAU },
{ 0x3FFE - 0x3fff, 0xCE168A77U, 0x25080CE1U },
{ 0x3FFC - 0x3fff, 0xDE1433A1U, 0x6C66B150U },
{ 0x3FFE - 0x3fff, 0xCB8727C0U, 0x65C393E0U },
{ 0x3FFC - 0x3fff, 0xEAE10B5AU, 0x7DDC8ADDU },
{ 0x3FFE - 0x3fff, 0xC907DA4EU, 0x871146ADU },
{ 0x3FFC - 0x3fff, 0xF7856E5EU, 0xE2C9B291U },
{ 0x3FFE - 0x3fff, 0xC6980C69U, 0x80C6980CU },
{ 0x3FFD - 0x3fff, 0x82012CA5U, 0xA68206D7U },
{ 0x3FFE - 0x3fff, 0xC4372F85U, 0x5D824CA6U },
{ 0x3FFD - 0x3fff, 0x882C5FCDU, 0x7256A8C5U },
{ 0x3FFE - 0x3fff, 0xC1E4BBD5U, 0x95F6E947U },
{ 0x3FFD - 0x3fff, 0x8E44C60BU, 0x4CCFD7DEU },
{ 0x3FFE - 0x3fff, 0xBFA02FE8U, 0x0BFA02FFU },
{ 0x3FFD - 0x3fff, 0x944AD09EU, 0xF4351AF6U },
{ 0x3FFE - 0x3fff, 0xBD691047U, 0x07661AA3U },
{ 0x3FFD - 0x3fff, 0x9A3EECD4U, 0xC3EAA6B2U },
{ 0x3FFE - 0x3fff, 0xBB3EE721U, 0xA54D880CU },
{ 0x3FFD - 0x3fff, 0xA0218434U, 0x353F1DE8U },
{ 0x3FFE - 0x3fff, 0xB92143FAU, 0x36F5E02EU },
{ 0x3FFD - 0x3fff, 0xA5F2FCABU, 0xBBC506DAU },
{ 0x3FFE - 0x3fff, 0xB70FBB5AU, 0x19BE3659U },
{ 0x3FFD - 0x3fff, 0xABB3B8BAU, 0x2AD362A5U },
{ 0x3FFE - 0x3fff, 0xB509E68AU, 0x9B94821FU },
{ 0x3FFD - 0x3fff, 0xB1641795U, 0xCE3CA97BU },
{ 0x3FFE - 0x3fff, 0xB30F6352U, 0x8917C80BU },
{ 0x3FFD - 0x3fff, 0xB7047551U, 0x5D0F1C61U },
{ 0x3FFE - 0x3fff, 0xB11FD3B8U, 0x0B11FD3CU },
{ 0x3FFD - 0x3fff, 0xBC952AFEU, 0xEA3D13E1U },
{ 0x3FFE - 0x3fff, 0xAF3ADDC6U, 0x80AF3ADEU },
{ 0x3FFD - 0x3fff, 0xC2168ED0U, 0xF458BA4AU },
{ 0x3FFE - 0x3fff, 0xAD602B58U, 0x0AD602B6U },
{ 0x3FFD - 0x3fff, 0xC788F439U, 0xB3163BF1U },
{ 0x3FFE - 0x3fff, 0xAB8F69E2U, 0x8359CD11U },
{ 0x3FFD - 0x3fff, 0xCCECAC08U, 0xBF04565DU },
{ 0x3FFE - 0x3fff, 0xA9C84A47U, 0xA07F5638U },
{ 0x3FFD - 0x3fff, 0xD2420487U, 0x2DD85160U },
{ 0x3FFE - 0x3fff, 0xA80A80A8U, 0x0A80A80BU },
{ 0x3FFD - 0x3fff, 0xD7894992U, 0x3BC3588AU },
{ 0x3FFE - 0x3fff, 0xA655C439U, 0x2D7B73A8U },
{ 0x3FFD - 0x3fff, 0xDCC2C4B4U, 0x9887DACCU },
{ 0x3FFE - 0x3fff, 0xA4A9CF1DU, 0x96833751U },
{ 0x3FFD - 0x3fff, 0xE1EEBD3EU, 0x6D6A6B9EU },
{ 0x3FFE - 0x3fff, 0xA3065E3FU, 0xAE7CD0E0U },
{ 0x3FFD - 0x3fff, 0xE70D785CU, 0x2F9F5BDCU },
{ 0x3FFE - 0x3fff, 0xA16B312EU, 0xA8FC377DU },
{ 0x3FFD - 0x3fff, 0xEC1F392CU, 0x5179F283U },
{ 0x3FFE - 0x3fff, 0x9FD809FDU, 0x809FD80AU },
{ 0x3FFD - 0x3fff, 0xF12440D3U, 0xE36130E6U },
{ 0x3FFE - 0x3fff, 0x9E4CAD23U, 0xDD5F3A20U },
{ 0x3FFD - 0x3fff, 0xF61CCE92U, 0x346600BBU },
{ 0x3FFE - 0x3fff, 0x9CC8E160U, 0xC3FB19B9U },
{ 0x3FFD - 0x3fff, 0xFB091FD3U, 0x8145630AU },
{ 0x3FFE - 0x3fff, 0x9B4C6F9EU, 0xF03A3CAAU },
{ 0x3FFD - 0x3fff, 0xFFE97042U, 0xBFA4C2ADU },
{ 0x3FFE - 0x3fff, 0x99D722DAU, 0xBDE58F06U },
{ 0x3FFE - 0x3fff, 0x825EFCEDU, 0x49369330U },
{ 0x3FFE - 0x3fff, 0x9868C809U, 0x868C8098U },
{ 0x3FFE - 0x3fff, 0x84C37A7AU, 0xB9A905C9U },
{ 0x3FFE - 0x3fff, 0x97012E02U, 0x5C04B809U },
{ 0x3FFE - 0x3fff, 0x87224C2EU, 0x8E645FB7U },
{ 0x3FFE - 0x3fff, 0x95A02568U, 0x095A0257U },
{ 0x3FFE - 0x3fff, 0x897B8CACU, 0x9F7DE298U },
{ 0x3FFE - 0x3fff, 0x94458094U, 0x45809446U },
{ 0x3FFE - 0x3fff, 0x8BCF55DEU, 0xC4CD05FEU },
{ 0x3FFE - 0x3fff, 0x92F11384U, 0x0497889CU },
{ 0x3FFE - 0x3fff, 0x8E1DC0FBU, 0x89E125E5U },
{ 0x3FFE - 0x3fff, 0x91A2B3C4U, 0xD5E6F809U },
{ 0x3FFE - 0x3fff, 0x9066E68CU, 0x955B6C9BU },
{ 0x3FFE - 0x3fff, 0x905A3863U, 0x3E06C43BU },
{ 0x3FFE - 0x3fff, 0x92AADE74U, 0xC7BE59E0U },
{ 0x3FFE - 0x3fff, 0x8F1779D9U, 0xFDC3A219U },
{ 0x3FFE - 0x3fff, 0x94E9BFF6U, 0x15845643U },
{ 0x3FFE - 0x3fff, 0x8DDA5202U, 0x37694809U },
{ 0x3FFE - 0x3fff, 0x9723A1B7U, 0x20134203U },
{ 0x3FFE - 0x3fff, 0x8CA29C04U, 0x6514E023U },
{ 0x3FFE - 0x3fff, 0x995899C8U, 0x90EB8990U },
{ 0x3FFE - 0x3fff, 0x8B70344AU, 0x139BC75AU },
{ 0x3FFE - 0x3fff, 0x9B88BDAAU, 0x3A3DAE2FU },
{ 0x3FFE - 0x3fff, 0x8A42F870U, 0x5669DB46U },
{ 0x3FFE - 0x3fff, 0x9DB4224FU, 0xFFE1157CU },
{ 0x3FFE - 0x3fff, 0x891AC73AU, 0xE9819B50U },
{ 0x3FFE - 0x3fff, 0x9FDADC26U, 0x8B7A12DAU },
{ 0x3FFE - 0x3fff, 0x87F78087U, 0xF78087F8U },
{ 0x3FFE - 0x3fff, 0xA1FCFF17U, 0xCE733BD4U },
{ 0x3FFE - 0x3fff, 0x86D90544U, 0x7A34ACC6U },
{ 0x3FFE - 0x3fff, 0xA41A9E8FU, 0x5446FB9FU },
{ 0x3FFE - 0x3fff, 0x85BF3761U, 0x2CEE3C9BU },
{ 0x3FFE - 0x3fff, 0xA633CD7EU, 0x6771CD8BU },
{ 0x3FFE - 0x3fff, 0x84A9F9C8U, 0x084A9F9DU },
{ 0x3FFE - 0x3fff, 0xA8489E60U, 0x0B435A5EU },
{ 0x3FFE - 0x3fff, 0x83993052U, 0x3FBE3368U },
{ 0x3FFE - 0x3fff, 0xAA59233CU, 0xCCA4BD49U },
{ 0x3FFE - 0x3fff, 0x828CBFBEU, 0xB9A020A3U },
{ 0x3FFE - 0x3fff, 0xAC656DAEU, 0x6BCC4985U },
{ 0x3FFE - 0x3fff, 0x81848DA8U, 0xFAF0D277U },
{ 0x3FFE - 0x3fff, 0xAE6D8EE3U, 0x60BB2468U },
{ 0x3FFE - 0x3fff, 0x80808080U, 0x80808081U },
{ 0x3FFE - 0x3fff, 0xB07197A2U, 0x3C46C654U },
};
struct fpn *__fpu_logn(struct fpemu *fe);
/*
* natural log - algorithm taken from Motorola FPSP,
* except this doesn't bother to check for invalid input.
*/
struct fpn *
__fpu_logn(fe)
struct fpemu *fe;
{
static struct fpn X, F, U, V, W, KLOG2;
struct fpn *d;
int i, k;
CPYFPN(&X, &fe->fe_f2);
/* see if |X-1| < 1/16 approx. */
if ((-1 == X.fp_exp && (0xf07d0000U >> (31 - FP_LG)) <= X.fp_mant[0]) ||
(0 == X.fp_exp && X.fp_mant[0] <= (0x88410000U >> (31 - FP_LG)))) {
/* log near 1 */
#if FPE_DEBUG
printf("__fpu_logn: log near 1\n");
#endif
fpu_const(&fe->fe_f1, 0x32);
/* X+1 */
d = fpu_add(fe);
CPYFPN(&V, d);
CPYFPN(&fe->fe_f1, &X);
fpu_const(&fe->fe_f2, 0x32); /* 1.0 */
fe->fe_f2.fp_sign = 1; /* -1.0 */
/* X-1 */
d = fpu_add(fe);
CPYFPN(&fe->fe_f1, d);
/* 2(X-1) */
fe->fe_f1.fp_exp++; /* *= 2 */
CPYFPN(&fe->fe_f2, &V);
/* U=2(X-1)/(X+1) */
d = fpu_div(fe);
CPYFPN(&U, d);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, d);
/* V=U*U */
d = fpu_mul(fe);
CPYFPN(&V, d);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, d);
/* W=V*V */
d = fpu_mul(fe);
CPYFPN(&W, d);
/* calculate U+U*V*([B1+W*(B3+W*B5)]+[V*(B2+W*B4)]) */
/* B1+W*(B3+W*B5) part */
CPYFPN(&fe->fe_f1, d);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logB5);
/* W*B5 */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logB3);
/* B3+W*B5 */
d = fpu_add(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &W);
/* W*(B3+W*B5) */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logB1);
/* B1+W*(B3+W*B5) */
d = fpu_add(fe);
CPYFPN(&X, d);
/* [V*(B2+W*B4)] part */
CPYFPN(&fe->fe_f1, &W);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logB4);
/* W*B4 */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logB2);
/* B2+W*B4 */
d = fpu_add(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &V);
/* V*(B2+W*B4) */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &X);
/* B1+W*(B3+W*B5)+V*(B2+W*B4) */
d = fpu_add(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &V);
/* V*(B1+W*(B3+W*B5)+V*(B2+W*B4)) */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &U);
/* U*V*(B1+W*(B3+W*B5)+V*(B2+W*B4)) */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &U);
/* U+U*V*(B1+W*(B3+W*B5)+V*(B2+W*B4)) */
d = fpu_add(fe);
} else /* the usual case */ {
#if FPE_DEBUG
printf("__fpu_logn: the usual case. X=(%d,%08x,%08x...)\n",
X.fp_exp, X.fp_mant[0], X.fp_mant[1]);
#endif
k = X.fp_exp;
/* X <- Y */
X.fp_exp = fe->fe_f2.fp_exp = 0;
/* get the most significant 7 bits of X */
F.fp_class = FPC_NUM;
F.fp_sign = 0;
F.fp_exp = X.fp_exp;
F.fp_mant[0] = X.fp_mant[0] & (0xfe000000U >> (31 - FP_LG));
F.fp_mant[0] |= (0x01000000U >> (31 - FP_LG));
F.fp_mant[1] = F.fp_mant[2] = 0;
F.fp_sticky = 0;
#if FPE_DEBUG
printf("__fpu_logn: X=Y*2^k=(%d,%08x,%08x...)*2^%d\n",
fe->fe_f2.fp_exp, fe->fe_f2.fp_mant[0],
fe->fe_f2.fp_mant[1], k);
printf("__fpu_logn: F=(%d,%08x,%08x...)\n",
F.fp_exp, F.fp_mant[0], F.fp_mant[1]);
#endif
/* index to the table */
i = (F.fp_mant[0] >> (FP_LG - 7)) & 0x7e;
#if FPE_DEBUG
printf("__fpu_logn: index to logtbl i=%d(%x)\n", i, i);
#endif
CPYFPN(&fe->fe_f1, &F);
/* -F */
fe->fe_f1.fp_sign = 1;
/* Y-F */
d = fpu_add(fe);
CPYFPN(&fe->fe_f1, d);
/* fe_f2 = 1/F */
fe->fe_f2.fp_class = FPC_NUM;
fe->fe_f2.fp_sign = fe->fe_f2.fp_sticky = fe->fe_f2.fp_mant[2] = 0;
fe->fe_f2.fp_exp = logtbl[i].sp_exp;
fe->fe_f2.fp_mant[0] = (logtbl[i].sp_m0 >> (31 - FP_LG));
fe->fe_f2.fp_mant[1] = (logtbl[i].sp_m0 << (FP_LG + 1)) |
(logtbl[i].sp_m1 >> (31 - FP_LG));
fe->fe_f2.fp_mant[2] = (u_int)(logtbl[i].sp_m1 << (FP_LG + 1));
#if FPE_DEBUG
printf("__fpu_logn: 1/F=(%d,%08x,%08x...)\n", fe->fe_f2.fp_exp,
fe->fe_f2.fp_mant[0], fe->fe_f2.fp_mant[1]);
#endif
/* U = (Y-F) * (1/F) */
d = fpu_mul(fe);
CPYFPN(&U, d);
/* KLOG2 = K * ln(2) */
/* fe_f1 == (fpn)k */
fpu_explode(fe, &fe->fe_f1, FTYPE_LNG, &k);
(void)fpu_const(&fe->fe_f2, 0x30 /* ln(2) */);
#if FPE_DEBUG
printf("__fpu_logn: fp(k)=(%d,%08x,%08x...)\n", fe->fe_f1.fp_exp,
fe->fe_f1.fp_mant[0], fe->fe_f1.fp_mant[1]);
printf("__fpu_logn: ln(2)=(%d,%08x,%08x...)\n", fe->fe_f2.fp_exp,
fe->fe_f2.fp_mant[0], fe->fe_f2.fp_mant[1]);
#endif
/* K * LOGOF2 */
d = fpu_mul(fe);
CPYFPN(&KLOG2, d);
/* V=U*U */
CPYFPN(&fe->fe_f1, &U);
CPYFPN(&fe->fe_f2, &U);
d = fpu_mul(fe);
CPYFPN(&V, d);
/*
* approximation of LOG(1+U) by
* (U+V*(A1+V*(A3+V*A5)))+(U*V*(A2+V*(A4+V*A6)))
*/
/* (U+V*(A1+V*(A3+V*A5))) part */
CPYFPN(&fe->fe_f1, d);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logA5);
/* V*A5 */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logA3);
/* A3+V*A5 */
d = fpu_add(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &V);
/* V*(A3+V*A5) */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logA1);
/* A1+V*(A3+V*A5) */
d = fpu_add(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &V);
/* V*(A1+V*(A3+V*A5)) */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &U);
/* U+V*(A1+V*(A3+V*A5)) */
d = fpu_add(fe);
CPYFPN(&X, d);
/* (U*V*(A2+V*(A4+V*A6))) part */
CPYFPN(&fe->fe_f1, &V);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logA6);
/* V*A6 */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logA4);
/* A4+V*A6 */
d = fpu_add(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &V);
/* V*(A4+V*A6) */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
fpu_explode(fe, &fe->fe_f2, FTYPE_DBL, logA2);
/* A2+V*(A4+V*A6) */
d = fpu_add(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &V);
/* V*(A2+V*(A4+V*A6)) */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &U);
/* U*V*(A2+V*(A4+V*A6)) */
d = fpu_mul(fe);
CPYFPN(&fe->fe_f1, d);
i++;
/* fe_f2 = logtbl[i+1] (== LOG(F)) */
fe->fe_f2.fp_class = FPC_NUM;
fe->fe_f2.fp_sign = fe->fe_f2.fp_sticky = fe->fe_f2.fp_mant[2] = 0;
fe->fe_f2.fp_exp = logtbl[i].sp_exp;
fe->fe_f2.fp_mant[0] = (logtbl[i].sp_m0 >> (31 - FP_LG));
fe->fe_f2.fp_mant[1] = (logtbl[i].sp_m0 << (FP_LG + 1)) |
(logtbl[i].sp_m1 >> (31 - FP_LG));
fe->fe_f2.fp_mant[2] = (logtbl[i].sp_m1 << (FP_LG + 1));
#if FPE_DEBUG
printf("__fpu_logn: ln(F)=(%d,%08x,%08x,...)\n", fe->fe_f2.fp_exp,
fe->fe_f2.fp_mant[0], fe->fe_f2.fp_mant[1]);
#endif
/* LOG(F)+U*V*(A2+V*(A4+V*A6)) */
d = fpu_add(fe);
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &X);
/* LOG(F)+U+V*(A1+V*(A3+V*A5))+U*V*(A2+V*(A4+V*A6)) */
d = fpu_add(fe);
#if FPE_DEBUG
printf("__fpu_logn: ln(Y)=(%c,%d,%08x,%08x,%08x)\n",
d->fp_sign ? '-' : '+', d->fp_exp,
d->fp_mant[0], d->fp_mant[1], d->fp_mant[2]);
#endif
CPYFPN(&fe->fe_f1, d);
CPYFPN(&fe->fe_f2, &KLOG2);
/* K*LOGOF2+LOG(F)+U+V*(A1+V*(A3+V*A5))+U*V*(A2+V*(A4+V*A6)) */
d = fpu_add(fe);
}
return d;
}
struct fpn *
fpu_log10(fe)
struct fpemu *fe;
{
struct fpn *fp = &fe->fe_f2;
u_int fpsr;
fpsr = fe->fe_fpsr & ~FPSR_EXCP; /* clear all exceptions */
if (fp->fp_class >= FPC_NUM) {
if (fp->fp_sign) { /* negative number or Inf */
fp = fpu_newnan(fe);
fpsr |= FPSR_OPERR;
} else if (fp->fp_class == FPC_NUM) {
/* the real work here */
fp = __fpu_logn(fe);
if (fp != &fe->fe_f1)
CPYFPN(&fe->fe_f1, fp);
(void)fpu_const(&fe->fe_f2, 0x31 /* ln(10) */);
fp = fpu_div(fe);
} /* else if fp == +Inf, return +Inf */
} else if (fp->fp_class == FPC_ZERO) {
/* return -Inf */
fp->fp_class = FPC_INF;
fp->fp_sign = 1;
fpsr |= FPSR_DZ;
} else if (fp->fp_class == FPC_SNAN) {
fpsr |= FPSR_SNAN;
fp = fpu_newnan(fe);
} else {
fp = fpu_newnan(fe);
}
fe->fe_fpsr = fpsr;
return fp;
}
struct fpn *
fpu_log2(fe)
struct fpemu *fe;
{
struct fpn *fp = &fe->fe_f2;
u_int fpsr;
fpsr = fe->fe_fpsr & ~FPSR_EXCP; /* clear all exceptions */
if (fp->fp_class >= FPC_NUM) {
if (fp->fp_sign) { /* negative number or Inf */
fp = fpu_newnan(fe);
fpsr |= FPSR_OPERR;
} else if (fp->fp_class == FPC_NUM) {
/* the real work here */
if (fp->fp_mant[0] == FP_1 && fp->fp_mant[1] == 0 &&
fp->fp_mant[2] == 0) {
/* fp == 2.0 ^ exp <--> log2(fp) == exp */
fpu_explode(fe, &fe->fe_f3, FTYPE_LNG, &fp->fp_exp);
fp = &fe->fe_f3;
} else {
fp = __fpu_logn(fe);
if (fp != &fe->fe_f1)
CPYFPN(&fe->fe_f1, fp);
(void)fpu_const(&fe->fe_f2, 0x30 /* ln(2) */);
fp = fpu_div(fe);
}
} /* else if fp == +Inf, return +Inf */
} else if (fp->fp_class == FPC_ZERO) {
/* return -Inf */
fp->fp_class = FPC_INF;
fp->fp_sign = 1;
fpsr |= FPSR_DZ;
} else if (fp->fp_class == FPC_SNAN) {
fpsr |= FPSR_SNAN;
fp = fpu_newnan(fe);
} else {
fp = fpu_newnan(fe);
}
fe->fe_fpsr = fpsr;
return fp;
}
struct fpn *
fpu_logn(fe)
struct fpemu *fe;
{
struct fpn *fp = &fe->fe_f2;
u_int fpsr;
fpsr = fe->fe_fpsr & ~FPSR_EXCP; /* clear all exceptions */
if (fp->fp_class >= FPC_NUM) {
if (fp->fp_sign) { /* negative number or Inf */
fp = fpu_newnan(fe);
fpsr |= FPSR_OPERR;
} else if (fp->fp_class == FPC_NUM) {
/* the real work here */
fp = __fpu_logn(fe);
} /* else if fp == +Inf, return +Inf */
} else if (fp->fp_class == FPC_ZERO) {
/* return -Inf */
fp->fp_class = FPC_INF;
fp->fp_sign = 1;
fpsr |= FPSR_DZ;
} else if (fp->fp_class == FPC_SNAN) {
fpsr |= FPSR_SNAN;
fp = fpu_newnan(fe);
} else {
fp = fpu_newnan(fe);
}
fe->fe_fpsr = fpsr;
return fp;
}
struct fpn *
fpu_lognp1(fe)
struct fpemu *fe;
{
struct fpn *fp;
/* build a 1.0 */
fp = fpu_const(&fe->fe_f1, 0x32); /* get 1.0 */
/* fp = 1.0 + f2 */
fp = fpu_add(fe);
/* copy the result to the src opr */
if (&fe->fe_f2 != fp)
CPYFPN(&fe->fe_f2, fp);
return fpu_logn(fe);
}
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