253 строки
7.0 KiB
C
253 строки
7.0 KiB
C
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/*
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* Linux/PA-RISC Project (http://www.parisc-linux.org/)
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*
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* Floating-point emulation code
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* Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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* BEGIN_DESC
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*
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* Purpose:
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* Single Floating-point Round to Integer
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* Double Floating-point Round to Integer
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* Quad Floating-point Round to Integer (returns unimplemented)
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*
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* External Interfaces:
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* dbl_frnd(srcptr,nullptr,dstptr,status)
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* sgl_frnd(srcptr,nullptr,dstptr,status)
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*
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* END_DESC
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*/
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#include "float.h"
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#include "sgl_float.h"
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#include "dbl_float.h"
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#include "cnv_float.h"
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/*
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* Single Floating-point Round to Integer
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*/
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/*ARGSUSED*/
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int
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sgl_frnd(sgl_floating_point *srcptr,
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unsigned int *nullptr,
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sgl_floating_point *dstptr,
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unsigned int *status)
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{
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register unsigned int src, result;
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register int src_exponent;
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register boolean inexact = FALSE;
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src = *srcptr;
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/*
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* check source operand for NaN or infinity
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*/
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if ((src_exponent = Sgl_exponent(src)) == SGL_INFINITY_EXPONENT) {
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/*
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* is signaling NaN?
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*/
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if (Sgl_isone_signaling(src)) {
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/* trap if INVALIDTRAP enabled */
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if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
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/* make NaN quiet */
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Set_invalidflag();
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Sgl_set_quiet(src);
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}
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/*
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* return quiet NaN or infinity
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*/
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*dstptr = src;
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return(NOEXCEPTION);
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}
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/*
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* Need to round?
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*/
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if ((src_exponent -= SGL_BIAS) >= SGL_P - 1) {
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*dstptr = src;
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return(NOEXCEPTION);
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}
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/*
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* Generate result
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*/
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if (src_exponent >= 0) {
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Sgl_clear_exponent_set_hidden(src);
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result = src;
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Sgl_rightshift(result,(SGL_P-1) - (src_exponent));
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/* check for inexact */
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if (Sgl_isinexact_to_fix(src,src_exponent)) {
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inexact = TRUE;
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/* round result */
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switch (Rounding_mode()) {
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case ROUNDPLUS:
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if (Sgl_iszero_sign(src)) Sgl_increment(result);
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break;
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case ROUNDMINUS:
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if (Sgl_isone_sign(src)) Sgl_increment(result);
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break;
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case ROUNDNEAREST:
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if (Sgl_isone_roundbit(src,src_exponent))
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if (Sgl_isone_stickybit(src,src_exponent)
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|| (Sgl_isone_lowmantissa(result)))
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Sgl_increment(result);
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}
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}
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Sgl_leftshift(result,(SGL_P-1) - (src_exponent));
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if (Sgl_isone_hiddenoverflow(result))
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Sgl_set_exponent(result,src_exponent + (SGL_BIAS+1));
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else Sgl_set_exponent(result,src_exponent + SGL_BIAS);
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}
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else {
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result = src; /* set sign */
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Sgl_setzero_exponentmantissa(result);
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/* check for inexact */
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if (Sgl_isnotzero_exponentmantissa(src)) {
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inexact = TRUE;
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/* round result */
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switch (Rounding_mode()) {
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case ROUNDPLUS:
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if (Sgl_iszero_sign(src))
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Sgl_set_exponent(result,SGL_BIAS);
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break;
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case ROUNDMINUS:
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if (Sgl_isone_sign(src))
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Sgl_set_exponent(result,SGL_BIAS);
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break;
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case ROUNDNEAREST:
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if (src_exponent == -1)
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if (Sgl_isnotzero_mantissa(src))
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Sgl_set_exponent(result,SGL_BIAS);
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}
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}
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}
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*dstptr = result;
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if (inexact) {
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if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
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else Set_inexactflag();
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}
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return(NOEXCEPTION);
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}
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/*
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* Double Floating-point Round to Integer
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*/
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/*ARGSUSED*/
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int
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dbl_frnd(
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dbl_floating_point *srcptr,
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unsigned int *nullptr,
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dbl_floating_point *dstptr,
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unsigned int *status)
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{
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register unsigned int srcp1, srcp2, resultp1, resultp2;
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register int src_exponent;
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register boolean inexact = FALSE;
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Dbl_copyfromptr(srcptr,srcp1,srcp2);
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/*
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* check source operand for NaN or infinity
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*/
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if ((src_exponent = Dbl_exponent(srcp1)) == DBL_INFINITY_EXPONENT) {
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/*
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* is signaling NaN?
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*/
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if (Dbl_isone_signaling(srcp1)) {
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/* trap if INVALIDTRAP enabled */
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if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION);
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/* make NaN quiet */
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Set_invalidflag();
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Dbl_set_quiet(srcp1);
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}
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/*
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* return quiet NaN or infinity
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*/
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Dbl_copytoptr(srcp1,srcp2,dstptr);
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return(NOEXCEPTION);
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}
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/*
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* Need to round?
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*/
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if ((src_exponent -= DBL_BIAS) >= DBL_P - 1) {
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Dbl_copytoptr(srcp1,srcp2,dstptr);
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return(NOEXCEPTION);
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}
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/*
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* Generate result
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*/
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if (src_exponent >= 0) {
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Dbl_clear_exponent_set_hidden(srcp1);
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resultp1 = srcp1;
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resultp2 = srcp2;
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Dbl_rightshift(resultp1,resultp2,(DBL_P-1) - (src_exponent));
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/* check for inexact */
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if (Dbl_isinexact_to_fix(srcp1,srcp2,src_exponent)) {
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inexact = TRUE;
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/* round result */
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switch (Rounding_mode()) {
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case ROUNDPLUS:
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if (Dbl_iszero_sign(srcp1))
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Dbl_increment(resultp1,resultp2);
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break;
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case ROUNDMINUS:
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if (Dbl_isone_sign(srcp1))
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Dbl_increment(resultp1,resultp2);
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break;
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case ROUNDNEAREST:
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if (Dbl_isone_roundbit(srcp1,srcp2,src_exponent))
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if (Dbl_isone_stickybit(srcp1,srcp2,src_exponent)
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|| (Dbl_isone_lowmantissap2(resultp2)))
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Dbl_increment(resultp1,resultp2);
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}
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}
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Dbl_leftshift(resultp1,resultp2,(DBL_P-1) - (src_exponent));
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if (Dbl_isone_hiddenoverflow(resultp1))
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Dbl_set_exponent(resultp1,src_exponent + (DBL_BIAS+1));
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else Dbl_set_exponent(resultp1,src_exponent + DBL_BIAS);
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}
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else {
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resultp1 = srcp1; /* set sign */
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Dbl_setzero_exponentmantissa(resultp1,resultp2);
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/* check for inexact */
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if (Dbl_isnotzero_exponentmantissa(srcp1,srcp2)) {
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inexact = TRUE;
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/* round result */
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switch (Rounding_mode()) {
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case ROUNDPLUS:
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if (Dbl_iszero_sign(srcp1))
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Dbl_set_exponent(resultp1,DBL_BIAS);
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break;
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case ROUNDMINUS:
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if (Dbl_isone_sign(srcp1))
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Dbl_set_exponent(resultp1,DBL_BIAS);
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break;
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case ROUNDNEAREST:
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if (src_exponent == -1)
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if (Dbl_isnotzero_mantissa(srcp1,srcp2))
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Dbl_set_exponent(resultp1,DBL_BIAS);
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}
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}
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}
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Dbl_copytoptr(resultp1,resultp2,dstptr);
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if (inexact) {
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if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION);
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else Set_inexactflag();
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}
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return(NOEXCEPTION);
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}
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