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Diffstat (limited to 'sys/arch/hppa/spmath/sfadd.c')
| -rw-r--r-- | sys/arch/hppa/spmath/sfadd.c | 518 |
1 files changed, 518 insertions, 0 deletions
diff --git a/sys/arch/hppa/spmath/sfadd.c b/sys/arch/hppa/spmath/sfadd.c new file mode 100644 index 00000000000..c1a3c5555fd --- /dev/null +++ b/sys/arch/hppa/spmath/sfadd.c @@ -0,0 +1,518 @@ +/* + * Copyright 1996 1995 by Open Software Foundation, Inc. + * All Rights Reserved + * + * Permission to use, copy, modify, and distribute this software and + * its documentation for any purpose and without fee is hereby granted, + * provided that the above copyright notice appears in all copies and + * that both the copyright notice and this permission notice appear in + * supporting documentation. + * + * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE + * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE. + * + * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR + * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM + * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, + * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION + * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + */ +/* + * pmk1.1 + */ +/* + * (c) Copyright 1986 HEWLETT-PACKARD COMPANY + * + * To anyone who acknowledges that this file is provided "AS IS" + * without any express or implied warranty: + * permission to use, copy, modify, and distribute this file + * for any purpose is hereby granted without fee, provided that + * the above copyright notice and this notice appears in all + * copies, and that the name of Hewlett-Packard Company not be + * used in advertising or publicity pertaining to distribution + * of the software without specific, written prior permission. + * Hewlett-Packard Company makes no representations about the + * suitability of this software for any purpose. + */ +/* $Source: /cvs/OpenBSD/src/sys/arch/hppa/spmath/sfadd.c,v $ + * $Revision: 1.1 $ $Author: mickey $ + * $State: Exp $ $Locker: $ + * $Date: 1998/06/23 20:34:06 $ + */ + +#include "../spmath/float.h" +#include "../spmath/sgl_float.h" + +/* + * Single_add: add two single precision values. + */ +sgl_fadd(leftptr, rightptr, dstptr, status) + sgl_floating_point *leftptr, *rightptr, *dstptr; + unsigned int *status; + { + register unsigned int left, right, result, extent; + register unsigned int signless_upper_left, signless_upper_right, save; + + + register int result_exponent, right_exponent, diff_exponent; + register int sign_save, jumpsize; + register boolean inexact = FALSE; + register boolean underflowtrap; + + /* Create local copies of the numbers */ + left = *leftptr; + right = *rightptr; + + /* A zero "save" helps discover equal operands (for later), * + * and is used in swapping operands (if needed). */ + Sgl_xortointp1(left,right,/*to*/save); + + /* + * check first operand for NaN's or infinity + */ + if ((result_exponent = Sgl_exponent(left)) == SGL_INFINITY_EXPONENT) + { + if (Sgl_iszero_mantissa(left)) + { + if (Sgl_isnotnan(right)) + { + if (Sgl_isinfinity(right) && save!=0) + { + /* + * invalid since operands are opposite signed infinity's + */ + if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(result); + *dstptr = result; + return(NOEXCEPTION); + } + /* + * return infinity + */ + *dstptr = left; + return(NOEXCEPTION); + } + } + else + { + /* + * is NaN; signaling or quiet? + */ + if (Sgl_isone_signaling(left)) + { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(left); + } + /* + * is second operand a signaling NaN? + */ + else if (Sgl_is_signalingnan(right)) + { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(right); + *dstptr = right; + return(NOEXCEPTION); + } + /* + * return quiet NaN + */ + *dstptr = left; + return(NOEXCEPTION); + } + } /* End left NaN or Infinity processing */ + /* + * check second operand for NaN's or infinity + */ + if (Sgl_isinfinity_exponent(right)) + { + if (Sgl_iszero_mantissa(right)) + { + /* return infinity */ + *dstptr = right; + return(NOEXCEPTION); + } + /* + * is NaN; signaling or quiet? + */ + if (Sgl_isone_signaling(right)) + { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(right); + } + /* + * return quiet NaN + */ + *dstptr = right; + return(NOEXCEPTION); + } /* End right NaN or Infinity processing */ + + /* Invariant: Must be dealing with finite numbers */ + + /* Compare operands by removing the sign */ + Sgl_copytoint_exponentmantissa(left,signless_upper_left); + Sgl_copytoint_exponentmantissa(right,signless_upper_right); + + /* sign difference selects add or sub operation. */ + if(Sgl_ismagnitudeless(signless_upper_left,signless_upper_right)) + { + /* Set the left operand to the larger one by XOR swap * + * First finish the first word using "save" */ + Sgl_xorfromintp1(save,right,/*to*/right); + Sgl_xorfromintp1(save,left,/*to*/left); + result_exponent = Sgl_exponent(left); + } + /* Invariant: left is not smaller than right. */ + + if((right_exponent = Sgl_exponent(right)) == 0) + { + /* Denormalized operands. First look for zeroes */ + if(Sgl_iszero_mantissa(right)) + { + /* right is zero */ + if(Sgl_iszero_exponentmantissa(left)) + { + /* Both operands are zeros */ + if(Is_rounding_mode(ROUNDMINUS)) + { + Sgl_or_signs(left,/*with*/right); + } + else + { + Sgl_and_signs(left,/*with*/right); + } + } + else + { + /* Left is not a zero and must be the result. Trapped + * underflows are signaled if left is denormalized. Result + * is always exact. */ + if( (result_exponent == 0) && Is_underflowtrap_enabled() ) + { + /* need to normalize results mantissa */ + sign_save = Sgl_signextendedsign(left); + Sgl_leftshiftby1(left); + Sgl_normalize(left,result_exponent); + Sgl_set_sign(left,/*using*/sign_save); + Sgl_setwrapped_exponent(left,result_exponent,unfl); + *dstptr = left; + return(UNDERFLOWEXCEPTION); + } + } + *dstptr = left; + return(NOEXCEPTION); + } + + /* Neither are zeroes */ + Sgl_clear_sign(right); /* Exponent is already cleared */ + if(result_exponent == 0 ) + { + /* Both operands are denormalized. The result must be exact + * and is simply calculated. A sum could become normalized and a + * difference could cancel to a true zero. */ + if( (/*signed*/int) save < 0 ) + { + Sgl_subtract(left,/*minus*/right,/*into*/result); + if(Sgl_iszero_mantissa(result)) + { + if(Is_rounding_mode(ROUNDMINUS)) + { + Sgl_setone_sign(result); + } + else + { + Sgl_setzero_sign(result); + } + *dstptr = result; + return(NOEXCEPTION); + } + } + else + { + Sgl_addition(left,right,/*into*/result); + if(Sgl_isone_hidden(result)) + { + *dstptr = result; + return(NOEXCEPTION); + } + } + if(Is_underflowtrap_enabled()) + { + /* need to normalize result */ + sign_save = Sgl_signextendedsign(result); + Sgl_leftshiftby1(result); + Sgl_normalize(result,result_exponent); + Sgl_set_sign(result,/*using*/sign_save); + Sgl_setwrapped_exponent(result,result_exponent,unfl); + *dstptr = result; + return(UNDERFLOWEXCEPTION); + } + *dstptr = result; + return(NOEXCEPTION); + } + right_exponent = 1; /* Set exponent to reflect different bias + * with denomalized numbers. */ + } + else + { + Sgl_clear_signexponent_set_hidden(right); + } + Sgl_clear_exponent_set_hidden(left); + diff_exponent = result_exponent - right_exponent; + + /* + * Special case alignment of operands that would force alignment + * beyond the extent of the extension. A further optimization + * could special case this but only reduces the path length for this + * infrequent case. + */ + if(diff_exponent > SGL_THRESHOLD) + { + diff_exponent = SGL_THRESHOLD; + } + + /* Align right operand by shifting to right */ + Sgl_right_align(/*operand*/right,/*shifted by*/diff_exponent, + /*and lower to*/extent); + + /* Treat sum and difference of the operands separately. */ + if( (/*signed*/int) save < 0 ) + { + /* + * Difference of the two operands. Their can be no overflow. A + * borrow can occur out of the hidden bit and force a post + * normalization phase. + */ + Sgl_subtract_withextension(left,/*minus*/right,/*with*/extent,/*into*/result); + if(Sgl_iszero_hidden(result)) + { + /* Handle normalization */ + /* A straight foward algorithm would now shift the result + * and extension left until the hidden bit becomes one. Not + * all of the extension bits need participate in the shift. + * Only the two most significant bits (round and guard) are + * needed. If only a single shift is needed then the guard + * bit becomes a significant low order bit and the extension + * must participate in the rounding. If more than a single + * shift is needed, then all bits to the right of the guard + * bit are zeros, and the guard bit may or may not be zero. */ + sign_save = Sgl_signextendedsign(result); + Sgl_leftshiftby1_withextent(result,extent,result); + + /* Need to check for a zero result. The sign and exponent + * fields have already been zeroed. The more efficient test + * of the full object can be used. + */ + if(Sgl_iszero(result)) + /* Must have been "x-x" or "x+(-x)". */ + { + if(Is_rounding_mode(ROUNDMINUS)) Sgl_setone_sign(result); + *dstptr = result; + return(NOEXCEPTION); + } + result_exponent--; + /* Look to see if normalization is finished. */ + if(Sgl_isone_hidden(result)) + { + if(result_exponent==0) + { + /* Denormalized, exponent should be zero. Left operand * + * was normalized, so extent (guard, round) was zero */ + goto underflow; + } + else + { + /* No further normalization is needed. */ + Sgl_set_sign(result,/*using*/sign_save); + Ext_leftshiftby1(extent); + goto round; + } + } + + /* Check for denormalized, exponent should be zero. Left * + * operand was normalized, so extent (guard, round) was zero */ + if(!(underflowtrap = Is_underflowtrap_enabled()) && + result_exponent==0) goto underflow; + + /* Shift extension to complete one bit of normalization and + * update exponent. */ + Ext_leftshiftby1(extent); + + /* Discover first one bit to determine shift amount. Use a + * modified binary search. We have already shifted the result + * one position right and still not found a one so the remainder + * of the extension must be zero and simplifies rounding. */ + /* Scan bytes */ + while(Sgl_iszero_hiddenhigh7mantissa(result)) + { + Sgl_leftshiftby8(result); + if((result_exponent -= 8) <= 0 && !underflowtrap) + goto underflow; + } + /* Now narrow it down to the nibble */ + if(Sgl_iszero_hiddenhigh3mantissa(result)) + { + /* The lower nibble contains the normalizing one */ + Sgl_leftshiftby4(result); + if((result_exponent -= 4) <= 0 && !underflowtrap) + goto underflow; + } + /* Select case were first bit is set (already normalized) + * otherwise select the proper shift. */ + if((jumpsize = Sgl_hiddenhigh3mantissa(result)) > 7) + { + /* Already normalized */ + if(result_exponent <= 0) goto underflow; + Sgl_set_sign(result,/*using*/sign_save); + Sgl_set_exponent(result,/*using*/result_exponent); + *dstptr = result; + return(NOEXCEPTION); + } + Sgl_sethigh4bits(result,/*using*/sign_save); + switch(jumpsize) + { + case 1: + { + Sgl_leftshiftby3(result); + result_exponent -= 3; + break; + } + case 2: + case 3: + { + Sgl_leftshiftby2(result); + result_exponent -= 2; + break; + } + case 4: + case 5: + case 6: + case 7: + { + Sgl_leftshiftby1(result); + result_exponent -= 1; + break; + } + } + if(result_exponent > 0) + { + Sgl_set_exponent(result,/*using*/result_exponent); + *dstptr = result; + return(NOEXCEPTION); /* Sign bit is already set */ + } + /* Fixup potential underflows */ + underflow: + if(Is_underflowtrap_enabled()) + { + Sgl_set_sign(result,sign_save); + Sgl_setwrapped_exponent(result,result_exponent,unfl); + *dstptr = result; + /* inexact = FALSE; */ + return(UNDERFLOWEXCEPTION); + } + /* + * Since we cannot get an inexact denormalized result, + * we can now return. + */ + Sgl_right_align(result,/*by*/(1-result_exponent),extent); + Sgl_clear_signexponent(result); + Sgl_set_sign(result,sign_save); + *dstptr = result; + return(NOEXCEPTION); + } /* end if(hidden...)... */ + /* Fall through and round */ + } /* end if(save < 0)... */ + else + { + /* Add magnitudes */ + Sgl_addition(left,right,/*to*/result); + if(Sgl_isone_hiddenoverflow(result)) + { + /* Prenormalization required. */ + Sgl_rightshiftby1_withextent(result,extent,extent); + Sgl_arithrightshiftby1(result); + result_exponent++; + } /* end if hiddenoverflow... */ + } /* end else ...add magnitudes... */ + + /* Round the result. If the extension is all zeros,then the result is + * exact. Otherwise round in the correct direction. No underflow is + * possible. If a postnormalization is necessary, then the mantissa is + * all zeros so no shift is needed. */ + round: + if(Ext_isnotzero(extent)) + { + inexact = TRUE; + switch(Rounding_mode()) + { + case ROUNDNEAREST: /* The default. */ + if(Ext_isone_sign(extent)) + { + /* at least 1/2 ulp */ + if(Ext_isnotzero_lower(extent) || + Sgl_isone_lowmantissa(result)) + { + /* either exactly half way and odd or more than 1/2ulp */ + Sgl_increment(result); + } + } + break; + + case ROUNDPLUS: + if(Sgl_iszero_sign(result)) + { + /* Round up positive results */ + Sgl_increment(result); + } + break; + + case ROUNDMINUS: + if(Sgl_isone_sign(result)) + { + /* Round down negative results */ + Sgl_increment(result); + } + + case ROUNDZERO:; + /* truncate is simple */ + } /* end switch... */ + if(Sgl_isone_hiddenoverflow(result)) result_exponent++; + } + if(result_exponent == SGL_INFINITY_EXPONENT) + { + /* Overflow */ + if(Is_overflowtrap_enabled()) + { + Sgl_setwrapped_exponent(result,result_exponent,ovfl); + *dstptr = result; + if (inexact) + if (Is_inexacttrap_enabled()) + return(OVERFLOWEXCEPTION | INEXACTEXCEPTION); + else Set_inexactflag(); + return(OVERFLOWEXCEPTION); + } + else + { + Set_overflowflag(); + inexact = TRUE; + Sgl_setoverflow(result); + } + } + else Sgl_set_exponent(result,result_exponent); + *dstptr = result; + if(inexact) + if(Is_inexacttrap_enabled()) return(INEXACTEXCEPTION); + else Set_inexactflag(); + return(NOEXCEPTION); + } |