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Diffstat (limited to '')
| -rw-r--r-- | arch/parisc/math-emu/dfrem.c | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/arch/parisc/math-emu/dfrem.c b/arch/parisc/math-emu/dfrem.c new file mode 100644 index 000000000..9243a5954 --- /dev/null +++ b/arch/parisc/math-emu/dfrem.c @@ -0,0 +1,284 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Linux/PA-RISC Project (http://www.parisc-linux.org/) + * + * Floating-point emulation code + * Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org> + */ +/* + * BEGIN_DESC + * + * File: + * @(#) pa/spmath/dfrem.c $Revision: 1.1 $ + * + * Purpose: + * Double Precision Floating-point Remainder + * + * External Interfaces: + * dbl_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 "dbl_float.h" + +/* + * Double Precision Floating-point Remainder + */ + +int +dbl_frem (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 resultp1, resultp2; + register int opnd1_exponent, opnd2_exponent, dest_exponent, stepcount; + register boolean roundup = FALSE; + + Dbl_copyfromptr(srcptr1,opnd1p1,opnd1p2); + Dbl_copyfromptr(srcptr2,opnd2p1,opnd2p2); + /* + * check first operand for NaN's or infinity + */ + if ((opnd1_exponent = Dbl_exponent(opnd1p1)) == DBL_INFINITY_EXPONENT) { + if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { + if (Dbl_isnotnan(opnd2p1,opnd2p2)) { + /* invalid since first operand is infinity */ + if (Is_invalidtrap_enabled()) + return(INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(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 ((opnd2_exponent = Dbl_exponent(opnd2p1)) == DBL_INFINITY_EXPONENT) { + if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { + /* + * return first operand + */ + Dbl_copytoptr(opnd1p1,opnd1p2,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); + } + /* + * check second operand for zero + */ + if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) { + /* invalid since second operand is zero */ + if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + + /* + * get sign of result + */ + resultp1 = opnd1p1; + + /* + * check for denormalized operands + */ + if (opnd1_exponent == 0) { + /* check for zero */ + if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { + Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); + return(NOEXCEPTION); + } + /* normalize, then continue */ + opnd1_exponent = 1; + Dbl_normalize(opnd1p1,opnd1p2,opnd1_exponent); + } + else { + Dbl_clear_signexponent_set_hidden(opnd1p1); + } + if (opnd2_exponent == 0) { + /* normalize, then continue */ + opnd2_exponent = 1; + Dbl_normalize(opnd2p1,opnd2p2,opnd2_exponent); + } + else { + Dbl_clear_signexponent_set_hidden(opnd2p1); + } + + /* 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 && + Dbl_isgreaterthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) { + /* set sign */ + Dbl_allp1(resultp1) = ~Dbl_allp1(resultp1); + /* align opnd2 with opnd1 */ + Dbl_leftshiftby1(opnd2p1,opnd2p2); + Dbl_subtract(opnd2p1,opnd2p2,opnd1p1,opnd1p2, + opnd2p1,opnd2p2); + /* now normalize */ + while (Dbl_iszero_hidden(opnd2p1)) { + Dbl_leftshiftby1(opnd2p1,opnd2p2); + dest_exponent--; + } + Dbl_set_exponentmantissa(resultp1,resultp2,opnd2p1,opnd2p2); + goto testforunderflow; + } + /* + * opnd1/opnd2 <= 1/2 + * + * In this case n will round to zero, so + * r = opnd1 + */ + Dbl_set_exponentmantissa(resultp1,resultp2,opnd1p1,opnd1p2); + dest_exponent = opnd1_exponent; + goto testforunderflow; + } + + /* + * Generate result + * + * Do iterative subtract until remainder is less than operand 2. + */ + while (stepcount-- > 0 && (Dbl_allp1(opnd1p1) || Dbl_allp2(opnd1p2))) { + if (Dbl_isnotlessthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) { + Dbl_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2,opnd1p1,opnd1p2); + } + Dbl_leftshiftby1(opnd1p1,opnd1p2); + } + /* + * Do last subtract, then determine which way to round if remainder + * is exactly 1/2 of opnd2 + */ + if (Dbl_isnotlessthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) { + Dbl_subtract(opnd1p1,opnd1p2,opnd2p1,opnd2p2,opnd1p1,opnd1p2); + roundup = TRUE; + } + if (stepcount > 0 || Dbl_iszero(opnd1p1,opnd1p2)) { + /* division is exact, remainder is zero */ + Dbl_setzero_exponentmantissa(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + 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. + */ + Dbl_leftshiftby1(opnd1p1,opnd1p2); + if (Dbl_isgreaterthan(opnd1p1,opnd1p2,opnd2p1,opnd2p2)) { + Dbl_invert_sign(resultp1); + Dbl_leftshiftby1(opnd2p1,opnd2p2); + Dbl_subtract(opnd2p1,opnd2p2,opnd1p1,opnd1p2,opnd1p1,opnd1p2); + } + /* check for remainder being exactly 1/2 of opnd2 */ + else if (Dbl_isequal(opnd1p1,opnd1p2,opnd2p1,opnd2p2) && roundup) { + Dbl_invert_sign(resultp1); + } + + /* normalize result's mantissa */ + while (Dbl_iszero_hidden(opnd1p1)) { + dest_exponent--; + Dbl_leftshiftby1(opnd1p1,opnd1p2); + } + Dbl_set_exponentmantissa(resultp1,resultp2,opnd1p1,opnd1p2); + + /* + * Test for underflow + */ + testforunderflow: + if (dest_exponent <= 0) { + /* trap if UNDERFLOWTRAP enabled */ + if (Is_underflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Dbl_setwrapped_exponent(resultp1,dest_exponent,unfl); + /* frem is always exact */ + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(UNDERFLOWEXCEPTION); + } + /* + * denormalize result or set to signed zero + */ + if (dest_exponent >= (1 - DBL_P)) { + Dbl_rightshift_exponentmantissa(resultp1,resultp2, + 1-dest_exponent); + } + else { + Dbl_setzero_exponentmantissa(resultp1,resultp2); + } + } + else Dbl_set_exponent(resultp1,dest_exponent); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); +} |