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diff --git a/sys/gnu/i386/fpemul/poly_l2.c b/sys/gnu/i386/fpemul/poly_l2.c
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-/*
- * poly_l2.c
- *
- * Compute the base 2 log of a FPU_REG, using a polynomial approximation.
- *
- *
- * Copyright (C) 1992,1993,1994
- * W. Metzenthen, 22 Parker St, Ormond, Vic 3163,
- * Australia. E-mail billm@vaxc.cc.monash.edu.au
- * All rights reserved.
- *
- * This copyright notice covers the redistribution and use of the
- * FPU emulator developed by W. Metzenthen. It covers only its use
- * in the 386BSD, FreeBSD and NetBSD operating systems. Any other
- * use is not permitted under this copyright.
- *
- * 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 include information specifying
- * that source code for the emulator is freely available and include
- * either:
- * a) an offer to provide the source code for a nominal distribution
- * fee, or
- * b) list at least two alternative methods whereby the source
- * can be obtained, e.g. a publically accessible bulletin board
- * and an anonymous ftp site from which the software can be
- * downloaded.
- * 3. All advertising materials specifically mentioning features or use of
- * this emulator must acknowledge that it was developed by W. Metzenthen.
- * 4. The name of W. Metzenthen may not be used to endorse or promote
- * products derived from this software without specific prior written
- * permission.
- *
- * THIS SOFTWARE IS PROVIDED ``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
- * W. METZENTHEN 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.
- *
- *
- * The purpose of this copyright, based upon the Berkeley copyright, is to
- * ensure that the covered software remains freely available to everyone.
- *
- * The software (with necessary differences) is also available, but under
- * the terms of the GNU copyleft, for the Linux operating system and for
- * the djgpp ms-dos extender.
- *
- * W. Metzenthen June 1994.
- *
- *
- * $FreeBSD$
- *
- */
-
-
-#include <gnu/i386/fpemul/reg_constant.h>
-#include <gnu/i386/fpemul/control_w.h>
-
-
-
-#define HIPOWER 9
-static unsigned short lterms[HIPOWER][4] =
-{
- /* Ideal computation with these coeffs gives about 64.6 bit rel
- * accuracy. */
- {0xe177, 0xb82f, 0x7652, 0x7154},
- {0xee0f, 0xe80f, 0x2770, 0x7b1c},
- {0x0fc0, 0xbe87, 0xb143, 0x49dd},
- {0x78b9, 0xdadd, 0xec54, 0x34c2},
- {0x003a, 0x5de9, 0x628b, 0x2909},
- {0x5588, 0xed16, 0x4abf, 0x2193},
- {0xb461, 0x85f7, 0x347a, 0x1c6a},
- {0x0975, 0x87b3, 0xd5bf, 0x1876},
- {0xe85c, 0xcec9, 0x84e7, 0x187d}
-};
-
-
-
-
-/*--- poly_l2() -------------------------------------------------------------+
- | Base 2 logarithm by a polynomial approximation. |
- +---------------------------------------------------------------------------*/
-void
-poly_l2(FPU_REG * arg, FPU_REG * result)
-{
- short exponent;
- char zero; /* flag for an Xx == 0 */
- unsigned short bits, shift;
- long long Xsq;
- FPU_REG accum, denom, num, Xx;
-
-
- exponent = arg->exp - EXP_BIAS;
-
- accum.tag = TW_Valid; /* set the tags to Valid */
-
- if (arg->sigh > (unsigned) 0xb504f334) {
- /* This is good enough for the computation of the polynomial
- * sum, but actually results in a loss of precision for the
- * computation of Xx. This will matter only if exponent
- * becomes zero. */
- exponent++;
- accum.sign = 1; /* sign to negative */
- num.exp = EXP_BIAS; /* needed to prevent errors in div
- * routine */
- reg_u_div(&CONST_1, arg, &num, FULL_PRECISION);
- } else {
- accum.sign = 0; /* set the sign to positive */
- num.sigl = arg->sigl; /* copy the mantissa */
- num.sigh = arg->sigh;
- }
-
-
- /* shift num left, lose the ms bit */
- num.sigh <<= 1;
- if (num.sigl & 0x80000000)
- num.sigh |= 1;
- num.sigl <<= 1;
-
- denom.sigl = num.sigl;
- denom.sigh = num.sigh;
- poly_div4((long long *) &(denom.sigl));
- denom.sigh += 0x80000000; /* set the msb */
- Xx.exp = EXP_BIAS; /* needed to prevent errors in div routine */
- reg_u_div(&num, &denom, &Xx, FULL_PRECISION);
-
- zero = !(Xx.sigh | Xx.sigl);
-
- mul64((long long *) &Xx.sigl, (long long *) &Xx.sigl, &Xsq);
- poly_div16(&Xsq);
-
- accum.exp = -1; /* exponent of accum */
-
- /* Do the basic fixed point polynomial evaluation */
- polynomial((unsigned *) &accum.sigl, (unsigned *) &Xsq, lterms, HIPOWER - 1);
-
- if (!exponent) {
- /* If the exponent is zero, then we would lose precision by
- * sticking to fixed point computation here */
- /* We need to re-compute Xx because of loss of precision. */
- FPU_REG lXx;
- char sign;
-
- sign = accum.sign;
- accum.sign = 0;
-
- /* make accum compatible and normalize */
- accum.exp = EXP_BIAS + accum.exp;
- normalize(&accum);
-
- if (zero) {
- reg_move(&CONST_Z, result);
- } else {
- /* we need to re-compute lXx to better accuracy */
- num.tag = TW_Valid; /* set the tags to Vaild */
- num.sign = 0; /* set the sign to positive */
- num.exp = EXP_BIAS - 1;
- if (sign) {
- /* The argument is of the form 1-x */
- /* Use 1-1/(1-x) = x/(1-x) */
- *((long long *) &num.sigl) = -*((long long *) &(arg->sigl));
- normalize(&num);
- reg_div(&num, arg, &num, FULL_PRECISION);
- } else {
- normalize(&num);
- }
-
- denom.tag = TW_Valid; /* set the tags to Valid */
- denom.sign = SIGN_POS; /* set the sign to positive */
- denom.exp = EXP_BIAS;
-
- reg_div(&num, &denom, &lXx, FULL_PRECISION);
-
- reg_u_mul(&lXx, &accum, &accum, FULL_PRECISION);
-
- reg_u_add(&lXx, &accum, result, FULL_PRECISION);
-
- normalize(result);
- }
-
- result->sign = sign;
- return;
- }
- mul64((long long *) &accum.sigl,
- (long long *) &Xx.sigl, (long long *) &accum.sigl);
-
- *((long long *) (&accum.sigl)) += *((long long *) (&Xx.sigl));
-
- if (Xx.sigh > accum.sigh) {
- /* There was an overflow */
-
- poly_div2((long long *) &accum.sigl);
- accum.sigh |= 0x80000000;
- accum.exp++;
- }
- /* When we add the exponent to the accum result later, we will require
- * that their signs are the same. Here we ensure that this is so. */
- if (exponent && ((exponent < 0) ^ (accum.sign))) {
- /* signs are different */
-
- accum.sign = !accum.sign;
-
- /* An exceptional case is when accum is zero */
- if (accum.sigl | accum.sigh) {
- /* find 1-accum */
- /* Shift to get exponent == 0 */
- if (accum.exp < 0) {
- poly_div2((long long *) &accum.sigl);
- accum.exp++;
- }
- /* Just negate, but throw away the sign */
- *((long long *) &(accum.sigl)) = -*((long long *) &(accum.sigl));
- if (exponent < 0)
- exponent++;
- else
- exponent--;
- }
- }
- shift = exponent >= 0 ? exponent : -exponent;
- bits = 0;
- if (shift) {
- if (accum.exp) {
- accum.exp++;
- poly_div2((long long *) &accum.sigl);
- }
- while (shift) {
- poly_div2((long long *) &accum.sigl);
- if (shift & 1)
- accum.sigh |= 0x80000000;
- shift >>= 1;
- bits++;
- }
- }
- /* Convert to 64 bit signed-compatible */
- accum.exp += bits + EXP_BIAS - 1;
-
- reg_move(&accum, result);
- normalize(result);
-
- return;
-}
-
-
-/*--- poly_l2p1() -----------------------------------------------------------+
- | Base 2 logarithm by a polynomial approximation. |
- | log2(x+1) |
- +---------------------------------------------------------------------------*/
-int
-poly_l2p1(FPU_REG * arg, FPU_REG * result)
-{
- char sign = 0;
- long long Xsq;
- FPU_REG arg_pl1, denom, accum, local_arg, poly_arg;
-
-
- sign = arg->sign;
-
- reg_add(arg, &CONST_1, &arg_pl1, FULL_PRECISION);
-
- if ((arg_pl1.sign) | (arg_pl1.tag)) { /* We need a valid positive
- * number! */
- return 1;
- }
- reg_add(&CONST_1, &arg_pl1, &denom, FULL_PRECISION);
- reg_div(arg, &denom, &local_arg, FULL_PRECISION);
- local_arg.sign = 0; /* Make the sign positive */
-
- /* Now we need to check that |local_arg| is less than 3-2*sqrt(2) =
- * 0.17157.. = .0xafb0ccc0 * 2^-2 */
-
- if (local_arg.exp >= EXP_BIAS - 3) {
- if ((local_arg.exp > EXP_BIAS - 3) ||
- (local_arg.sigh > (unsigned) 0xafb0ccc0)) {
- /* The argument is large */
- poly_l2(&arg_pl1, result);
- return 0;
- }
- }
- /* Make a copy of local_arg */
- reg_move(&local_arg, &poly_arg);
-
- /* Get poly_arg bits aligned as required */
- shrx((unsigned *) &(poly_arg.sigl), -(poly_arg.exp - EXP_BIAS + 3));
-
- mul64((long long *) &(poly_arg.sigl), (long long *) &(poly_arg.sigl), &Xsq);
- poly_div16(&Xsq);
-
- /* Do the basic fixed point polynomial evaluation */
- polynomial((u_int *) &accum.sigl, (unsigned *) &Xsq, lterms, HIPOWER - 1);
-
- accum.tag = TW_Valid; /* set the tags to Valid */
- accum.sign = SIGN_POS; /* and make accum positive */
-
- /* make accum compatible and normalize */
- accum.exp = EXP_BIAS - 1;
- normalize(&accum);
-
- reg_u_mul(&local_arg, &accum, &accum, FULL_PRECISION);
-
- reg_u_add(&local_arg, &accum, result, FULL_PRECISION);
-
- /* Multiply the result by 2 */
- result->exp++;
-
- result->sign = sign;
-
- return 0;
-}
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