| /* | |
| * Linux/PA-RISC Project (http://www.parisc-linux.org/) | |
| * | |
| * Floating-point emulation code | |
| * Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org> | |
| * | |
| * This program is free software; you can redistribute it and/or modify | |
| * it under the terms of the GNU General Public License as published by | |
| * the Free Software Foundation; either version 2, or (at your option) | |
| * any later version. | |
| * | |
| * This program is distributed in the hope that it will be useful, | |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| * GNU General Public License for more details. | |
| * | |
| * You should have received a copy of the GNU General Public License | |
| * along with this program; if not, write to the Free Software | |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| */ | |
| /* | |
| * BEGIN_DESC | |
| * | |
| * File: | |
| * @(#) pa/spmath/sfrem.c $Revision: 1.1 $ | |
| * | |
| * Purpose: | |
| * Single Precision Floating-point Remainder | |
| * | |
| * External Interfaces: | |
| * sgl_frem(srcptr1,srcptr2,dstptr,status) | |
| * | |
| * Internal Interfaces: | |
| * | |
| * Theory: | |
| * <<please update with a overview of the operation of this file>> | |
| * | |
| * END_DESC | |
| */ | |
| #include "float.h" | |
| #include "sgl_float.h" | |
| /* | |
| * Single Precision Floating-point Remainder | |
| */ | |
| int | |
| sgl_frem (sgl_floating_point * srcptr1, sgl_floating_point * srcptr2, | |
| sgl_floating_point * dstptr, unsigned int *status) | |
| { | |
| register unsigned int opnd1, opnd2, result; | |
| register int opnd1_exponent, opnd2_exponent, dest_exponent, stepcount; | |
| register boolean roundup = FALSE; | |
| opnd1 = *srcptr1; | |
| opnd2 = *srcptr2; | |
| /* | |
| * check first operand for NaN's or infinity | |
| */ | |
| if ((opnd1_exponent = Sgl_exponent(opnd1)) == SGL_INFINITY_EXPONENT) { | |
| if (Sgl_iszero_mantissa(opnd1)) { | |
| if (Sgl_isnotnan(opnd2)) { | |
| /* invalid since first operand is infinity */ | |
| if (Is_invalidtrap_enabled()) | |
| return(INVALIDEXCEPTION); | |
| Set_invalidflag(); | |
| Sgl_makequietnan(result); | |
| *dstptr = result; | |
| return(NOEXCEPTION); | |
| } | |
| } | |
| else { | |
| /* | |
| * is NaN; signaling or quiet? | |
| */ | |
| if (Sgl_isone_signaling(opnd1)) { | |
| /* trap if INVALIDTRAP enabled */ | |
| if (Is_invalidtrap_enabled()) | |
| return(INVALIDEXCEPTION); | |
| /* make NaN quiet */ | |
| Set_invalidflag(); | |
| Sgl_set_quiet(opnd1); | |
| } | |
| /* | |
| * is second operand a signaling NaN? | |
| */ | |
| else if (Sgl_is_signalingnan(opnd2)) { | |
| /* trap if INVALIDTRAP enabled */ | |
| if (Is_invalidtrap_enabled()) | |
| return(INVALIDEXCEPTION); | |
| /* make NaN quiet */ | |
| Set_invalidflag(); | |
| Sgl_set_quiet(opnd2); | |
| *dstptr = opnd2; | |
| return(NOEXCEPTION); | |
| } | |
| /* | |
| * return quiet NaN | |
| */ | |
| *dstptr = opnd1; | |
| return(NOEXCEPTION); | |
| } | |
| } | |
| /* | |
| * check second operand for NaN's or infinity | |
| */ | |
| if ((opnd2_exponent = Sgl_exponent(opnd2)) == SGL_INFINITY_EXPONENT) { | |
| if (Sgl_iszero_mantissa(opnd2)) { | |
| /* | |
| * return first operand | |
| */ | |
| *dstptr = opnd1; | |
| return(NOEXCEPTION); | |
| } | |
| /* | |
| * is NaN; signaling or quiet? | |
| */ | |
| if (Sgl_isone_signaling(opnd2)) { | |
| /* trap if INVALIDTRAP enabled */ | |
| if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); | |
| /* make NaN quiet */ | |
| Set_invalidflag(); | |
| Sgl_set_quiet(opnd2); | |
| } | |
| /* | |
| * return quiet NaN | |
| */ | |
| *dstptr = opnd2; | |
| return(NOEXCEPTION); | |
| } | |
| /* | |
| * check second operand for zero | |
| */ | |
| if (Sgl_iszero_exponentmantissa(opnd2)) { | |
| /* invalid since second operand is zero */ | |
| if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); | |
| Set_invalidflag(); | |
| Sgl_makequietnan(result); | |
| *dstptr = result; | |
| return(NOEXCEPTION); | |
| } | |
| /* | |
| * get sign of result | |
| */ | |
| result = opnd1; | |
| /* | |
| * check for denormalized operands | |
| */ | |
| if (opnd1_exponent == 0) { | |
| /* check for zero */ | |
| if (Sgl_iszero_mantissa(opnd1)) { | |
| *dstptr = opnd1; | |
| return(NOEXCEPTION); | |
| } | |
| /* normalize, then continue */ | |
| opnd1_exponent = 1; | |
| Sgl_normalize(opnd1,opnd1_exponent); | |
| } | |
| else { | |
| Sgl_clear_signexponent_set_hidden(opnd1); | |
| } | |
| if (opnd2_exponent == 0) { | |
| /* normalize, then continue */ | |
| opnd2_exponent = 1; | |
| Sgl_normalize(opnd2,opnd2_exponent); | |
| } | |
| else { | |
| Sgl_clear_signexponent_set_hidden(opnd2); | |
| } | |
| /* find result exponent and divide step loop count */ | |
| dest_exponent = opnd2_exponent - 1; | |
| stepcount = opnd1_exponent - opnd2_exponent; | |
| /* | |
| * check for opnd1/opnd2 < 1 | |
| */ | |
| if (stepcount < 0) { | |
| /* | |
| * check for opnd1/opnd2 > 1/2 | |
| * | |
| * In this case n will round to 1, so | |
| * r = opnd1 - opnd2 | |
| */ | |
| if (stepcount == -1 && Sgl_isgreaterthan(opnd1,opnd2)) { | |
| Sgl_all(result) = ~Sgl_all(result); /* set sign */ | |
| /* align opnd2 with opnd1 */ | |
| Sgl_leftshiftby1(opnd2); | |
| Sgl_subtract(opnd2,opnd1,opnd2); | |
| /* now normalize */ | |
| while (Sgl_iszero_hidden(opnd2)) { | |
| Sgl_leftshiftby1(opnd2); | |
| dest_exponent--; | |
| } | |
| Sgl_set_exponentmantissa(result,opnd2); | |
| goto testforunderflow; | |
| } | |
| /* | |
| * opnd1/opnd2 <= 1/2 | |
| * | |
| * In this case n will round to zero, so | |
| * r = opnd1 | |
| */ | |
| Sgl_set_exponentmantissa(result,opnd1); | |
| dest_exponent = opnd1_exponent; | |
| goto testforunderflow; | |
| } | |
| /* | |
| * Generate result | |
| * | |
| * Do iterative subtract until remainder is less than operand 2. | |
| */ | |
| while (stepcount-- > 0 && Sgl_all(opnd1)) { | |
| if (Sgl_isnotlessthan(opnd1,opnd2)) | |
| Sgl_subtract(opnd1,opnd2,opnd1); | |
| Sgl_leftshiftby1(opnd1); | |
| } | |
| /* | |
| * Do last subtract, then determine which way to round if remainder | |
| * is exactly 1/2 of opnd2 | |
| */ | |
| if (Sgl_isnotlessthan(opnd1,opnd2)) { | |
| Sgl_subtract(opnd1,opnd2,opnd1); | |
| roundup = TRUE; | |
| } | |
| if (stepcount > 0 || Sgl_iszero(opnd1)) { | |
| /* division is exact, remainder is zero */ | |
| Sgl_setzero_exponentmantissa(result); | |
| *dstptr = result; | |
| return(NOEXCEPTION); | |
| } | |
| /* | |
| * Check for cases where opnd1/opnd2 < n | |
| * | |
| * In this case the result's sign will be opposite that of | |
| * opnd1. The mantissa also needs some correction. | |
| */ | |
| Sgl_leftshiftby1(opnd1); | |
| if (Sgl_isgreaterthan(opnd1,opnd2)) { | |
| Sgl_invert_sign(result); | |
| Sgl_subtract((opnd2<<1),opnd1,opnd1); | |
| } | |
| /* check for remainder being exactly 1/2 of opnd2 */ | |
| else if (Sgl_isequal(opnd1,opnd2) && roundup) { | |
| Sgl_invert_sign(result); | |
| } | |
| /* normalize result's mantissa */ | |
| while (Sgl_iszero_hidden(opnd1)) { | |
| dest_exponent--; | |
| Sgl_leftshiftby1(opnd1); | |
| } | |
| Sgl_set_exponentmantissa(result,opnd1); | |
| /* | |
| * Test for underflow | |
| */ | |
| testforunderflow: | |
| if (dest_exponent <= 0) { | |
| /* trap if UNDERFLOWTRAP enabled */ | |
| if (Is_underflowtrap_enabled()) { | |
| /* | |
| * Adjust bias of result | |
| */ | |
| Sgl_setwrapped_exponent(result,dest_exponent,unfl); | |
| *dstptr = result; | |
| /* frem is always exact */ | |
| return(UNDERFLOWEXCEPTION); | |
| } | |
| /* | |
| * denormalize result or set to signed zero | |
| */ | |
| if (dest_exponent >= (1 - SGL_P)) { | |
| Sgl_rightshift_exponentmantissa(result,1-dest_exponent); | |
| } | |
| else { | |
| Sgl_setzero_exponentmantissa(result); | |
| } | |
| } | |
| else Sgl_set_exponent(result,dest_exponent); | |
| *dstptr = result; | |
| return(NOEXCEPTION); | |
| } |