diff options
Diffstat (limited to 'ANDROID_3.4.5/arch/parisc/math-emu/sfsub.c')
| -rw-r--r-- | ANDROID_3.4.5/arch/parisc/math-emu/sfsub.c | 521 |
1 files changed, 0 insertions, 521 deletions
diff --git a/ANDROID_3.4.5/arch/parisc/math-emu/sfsub.c b/ANDROID_3.4.5/arch/parisc/math-emu/sfsub.c deleted file mode 100644 index 5f90d0f3..00000000 --- a/ANDROID_3.4.5/arch/parisc/math-emu/sfsub.c +++ /dev/null @@ -1,521 +0,0 @@ -/* - * 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/sfsub.c $Revision: 1.1 $ - * - * Purpose: - * Single_subtract: subtract two single precision values. - * - * External Interfaces: - * sgl_fsub(leftptr, rightptr, 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_subtract: subtract two single precision values. - */ -int -sgl_fsub( - sgl_floating_point *leftptr, - sgl_floating_point *rightptr, - sgl_floating_point *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, 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 same 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 */ - Sgl_invert_sign(right); - *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 sub or add 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); - Sgl_invert_sign(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 */ - Sgl_invert_sign(right); - 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; - /* inexact = FALSE */ - 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; - /* inexact = FALSE */ - 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 straightforward 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; /* Sign bit is already set */ - return(NOEXCEPTION); - } - /* 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 ...sub 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); - } |