diff options
Diffstat (limited to 'kernel/arch/parisc/math-emu/dfmpy.c')
| -rw-r--r-- | kernel/arch/parisc/math-emu/dfmpy.c | 394 |
1 files changed, 394 insertions, 0 deletions
diff --git a/kernel/arch/parisc/math-emu/dfmpy.c b/kernel/arch/parisc/math-emu/dfmpy.c new file mode 100644 index 000000000..4380f5a62 --- /dev/null +++ b/kernel/arch/parisc/math-emu/dfmpy.c @@ -0,0 +1,394 @@ +/* + * 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/dfmpy.c $Revision: 1.1 $ + * + * Purpose: + * Double Precision Floating-point Multiply + * + * External Interfaces: + * dbl_fmpy(srcptr1,srcptr2,dstptr,status) + * + * Internal Interfaces: + * + * Theory: + * <<please update with a overview of the operation of this file>> + * + * END_DESC +*/ + + +#include "float.h" +#include "dbl_float.h" + +/* + * Double Precision Floating-point Multiply + */ + +int +dbl_fmpy( + dbl_floating_point *srcptr1, + dbl_floating_point *srcptr2, + dbl_floating_point *dstptr, + unsigned int *status) +{ + register unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2; + register unsigned int opnd3p1, opnd3p2, resultp1, resultp2; + register int dest_exponent, count; + register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE; + boolean is_tiny; + + Dbl_copyfromptr(srcptr1,opnd1p1,opnd1p2); + Dbl_copyfromptr(srcptr2,opnd2p1,opnd2p2); + + /* + * set sign bit of result + */ + if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1)) + Dbl_setnegativezerop1(resultp1); + else Dbl_setzerop1(resultp1); + /* + * check first operand for NaN's or infinity + */ + if (Dbl_isinfinity_exponent(opnd1p1)) { + if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { + if (Dbl_isnotnan(opnd2p1,opnd2p2)) { + if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) { + /* + * invalid since operands are infinity + * and zero + */ + if (Is_invalidtrap_enabled()) + return(INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + /* + * return infinity + */ + Dbl_setinfinity_exponentmantissa(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + } + else { + /* + * is NaN; signaling or quiet? + */ + if (Dbl_isone_signaling(opnd1p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd1p1); + } + /* + * is second operand a signaling NaN? + */ + else if (Dbl_is_signalingnan(opnd2p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd2p1); + Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); + return(NOEXCEPTION); + } + /* + * return quiet NaN + */ + Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); + return(NOEXCEPTION); + } + } + /* + * check second operand for NaN's or infinity + */ + if (Dbl_isinfinity_exponent(opnd2p1)) { + if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { + if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) { + /* invalid since operands are zero & infinity */ + if (Is_invalidtrap_enabled()) + return(INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(opnd2p1,opnd2p2); + Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); + return(NOEXCEPTION); + } + /* + * return infinity + */ + Dbl_setinfinity_exponentmantissa(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + /* + * is NaN; signaling or quiet? + */ + if (Dbl_isone_signaling(opnd2p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd2p1); + } + /* + * return quiet NaN + */ + Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); + return(NOEXCEPTION); + } + /* + * Generate exponent + */ + dest_exponent = Dbl_exponent(opnd1p1) + Dbl_exponent(opnd2p1) -DBL_BIAS; + + /* + * Generate mantissa + */ + if (Dbl_isnotzero_exponent(opnd1p1)) { + /* set hidden bit */ + Dbl_clear_signexponent_set_hidden(opnd1p1); + } + else { + /* check for zero */ + if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { + Dbl_setzero_exponentmantissa(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + /* is denormalized, adjust exponent */ + Dbl_clear_signexponent(opnd1p1); + Dbl_leftshiftby1(opnd1p1,opnd1p2); + Dbl_normalize(opnd1p1,opnd1p2,dest_exponent); + } + /* opnd2 needs to have hidden bit set with msb in hidden bit */ + if (Dbl_isnotzero_exponent(opnd2p1)) { + Dbl_clear_signexponent_set_hidden(opnd2p1); + } + else { + /* check for zero */ + if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { + Dbl_setzero_exponentmantissa(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + /* is denormalized; want to normalize */ + Dbl_clear_signexponent(opnd2p1); + Dbl_leftshiftby1(opnd2p1,opnd2p2); + Dbl_normalize(opnd2p1,opnd2p2,dest_exponent); + } + + /* Multiply two source mantissas together */ + + /* make room for guard bits */ + Dbl_leftshiftby7(opnd2p1,opnd2p2); + Dbl_setzero(opnd3p1,opnd3p2); + /* + * Four bits at a time are inspected in each loop, and a + * simple shift and add multiply algorithm is used. + */ + for (count=1;count<=DBL_P;count+=4) { + stickybit |= Dlow4p2(opnd3p2); + Dbl_rightshiftby4(opnd3p1,opnd3p2); + if (Dbit28p2(opnd1p2)) { + /* Twoword_add should be an ADDC followed by an ADD. */ + Twoword_add(opnd3p1, opnd3p2, opnd2p1<<3 | opnd2p2>>29, + opnd2p2<<3); + } + if (Dbit29p2(opnd1p2)) { + Twoword_add(opnd3p1, opnd3p2, opnd2p1<<2 | opnd2p2>>30, + opnd2p2<<2); + } + if (Dbit30p2(opnd1p2)) { + Twoword_add(opnd3p1, opnd3p2, opnd2p1<<1 | opnd2p2>>31, + opnd2p2<<1); + } + if (Dbit31p2(opnd1p2)) { + Twoword_add(opnd3p1, opnd3p2, opnd2p1, opnd2p2); + } + Dbl_rightshiftby4(opnd1p1,opnd1p2); + } + if (Dbit3p1(opnd3p1)==0) { + Dbl_leftshiftby1(opnd3p1,opnd3p2); + } + else { + /* result mantissa >= 2. */ + dest_exponent++; + } + /* check for denormalized result */ + while (Dbit3p1(opnd3p1)==0) { + Dbl_leftshiftby1(opnd3p1,opnd3p2); + dest_exponent--; + } + /* + * check for guard, sticky and inexact bits + */ + stickybit |= Dallp2(opnd3p2) << 25; + guardbit = (Dallp2(opnd3p2) << 24) >> 31; + inexact = guardbit | stickybit; + + /* align result mantissa */ + Dbl_rightshiftby8(opnd3p1,opnd3p2); + + /* + * round result + */ + if (inexact && (dest_exponent>0 || Is_underflowtrap_enabled())) { + Dbl_clear_signexponent(opnd3p1); + switch (Rounding_mode()) { + case ROUNDPLUS: + if (Dbl_iszero_sign(resultp1)) + Dbl_increment(opnd3p1,opnd3p2); + break; + case ROUNDMINUS: + if (Dbl_isone_sign(resultp1)) + Dbl_increment(opnd3p1,opnd3p2); + break; + case ROUNDNEAREST: + if (guardbit) { + if (stickybit || Dbl_isone_lowmantissap2(opnd3p2)) + Dbl_increment(opnd3p1,opnd3p2); + } + } + if (Dbl_isone_hidden(opnd3p1)) dest_exponent++; + } + Dbl_set_mantissa(resultp1,resultp2,opnd3p1,opnd3p2); + + /* + * Test for overflow + */ + if (dest_exponent >= DBL_INFINITY_EXPONENT) { + /* trap if OVERFLOWTRAP enabled */ + if (Is_overflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Dbl_setwrapped_exponent(resultp1,dest_exponent,ovfl); + Dbl_copytoptr(resultp1,resultp2,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) + return (OVERFLOWEXCEPTION | INEXACTEXCEPTION); + else Set_inexactflag(); + return (OVERFLOWEXCEPTION); + } + inexact = TRUE; + Set_overflowflag(); + /* set result to infinity or largest number */ + Dbl_setoverflow(resultp1,resultp2); + } + /* + * Test for underflow + */ + else if (dest_exponent <= 0) { + /* trap if UNDERFLOWTRAP enabled */ + if (Is_underflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Dbl_setwrapped_exponent(resultp1,dest_exponent,unfl); + Dbl_copytoptr(resultp1,resultp2,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) + return (UNDERFLOWEXCEPTION | INEXACTEXCEPTION); + else Set_inexactflag(); + return (UNDERFLOWEXCEPTION); + } + + /* Determine if should set underflow flag */ + is_tiny = TRUE; + if (dest_exponent == 0 && inexact) { + switch (Rounding_mode()) { + case ROUNDPLUS: + if (Dbl_iszero_sign(resultp1)) { + Dbl_increment(opnd3p1,opnd3p2); + if (Dbl_isone_hiddenoverflow(opnd3p1)) + is_tiny = FALSE; + Dbl_decrement(opnd3p1,opnd3p2); + } + break; + case ROUNDMINUS: + if (Dbl_isone_sign(resultp1)) { + Dbl_increment(opnd3p1,opnd3p2); + if (Dbl_isone_hiddenoverflow(opnd3p1)) + is_tiny = FALSE; + Dbl_decrement(opnd3p1,opnd3p2); + } + break; + case ROUNDNEAREST: + if (guardbit && (stickybit || + Dbl_isone_lowmantissap2(opnd3p2))) { + Dbl_increment(opnd3p1,opnd3p2); + if (Dbl_isone_hiddenoverflow(opnd3p1)) + is_tiny = FALSE; + Dbl_decrement(opnd3p1,opnd3p2); + } + break; + } + } + + /* + * denormalize result or set to signed zero + */ + stickybit = inexact; + Dbl_denormalize(opnd3p1,opnd3p2,dest_exponent,guardbit, + stickybit,inexact); + + /* return zero or smallest number */ + if (inexact) { + switch (Rounding_mode()) { + case ROUNDPLUS: + if (Dbl_iszero_sign(resultp1)) { + Dbl_increment(opnd3p1,opnd3p2); + } + break; + case ROUNDMINUS: + if (Dbl_isone_sign(resultp1)) { + Dbl_increment(opnd3p1,opnd3p2); + } + break; + case ROUNDNEAREST: + if (guardbit && (stickybit || + Dbl_isone_lowmantissap2(opnd3p2))) { + Dbl_increment(opnd3p1,opnd3p2); + } + break; + } + if (is_tiny) Set_underflowflag(); + } + Dbl_set_exponentmantissa(resultp1,resultp2,opnd3p1,opnd3p2); + } + else Dbl_set_exponent(resultp1,dest_exponent); + /* check for inexact */ + Dbl_copytoptr(resultp1,resultp2,dstptr); + if (inexact) { + if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION); + else Set_inexactflag(); + } + return(NOEXCEPTION); +} |