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Diffstat (limited to 'arch/parisc/math-emu/sfdiv.c')
| -rw-r--r-- | arch/parisc/math-emu/sfdiv.c | 379 |
1 files changed, 379 insertions, 0 deletions
diff --git a/arch/parisc/math-emu/sfdiv.c b/arch/parisc/math-emu/sfdiv.c new file mode 100644 index 000000000..f1b439365 --- /dev/null +++ b/arch/parisc/math-emu/sfdiv.c @@ -0,0 +1,379 @@ +// 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/sfdiv.c $Revision: 1.1 $ + * + * Purpose: + * Single Precision Floating-point Divide + * + * External Interfaces: + * sgl_fdiv(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 Divide + */ + +int +sgl_fdiv (sgl_floating_point * srcptr1, sgl_floating_point * srcptr2, + sgl_floating_point * dstptr, unsigned int *status) +{ + register unsigned int opnd1, opnd2, opnd3, result; + register int dest_exponent, count; + register boolean inexact = FALSE, guardbit = FALSE, stickybit = FALSE; + boolean is_tiny; + + opnd1 = *srcptr1; + opnd2 = *srcptr2; + /* + * set sign bit of result + */ + if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2)) Sgl_setnegativezero(result); + else Sgl_setzero(result); + /* + * check first operand for NaN's or infinity + */ + if (Sgl_isinfinity_exponent(opnd1)) { + if (Sgl_iszero_mantissa(opnd1)) { + if (Sgl_isnotnan(opnd2)) { + if (Sgl_isinfinity(opnd2)) { + /* + * invalid since both operands + * are infinity + */ + if (Is_invalidtrap_enabled()) + return(INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(result); + *dstptr = result; + return(NOEXCEPTION); + } + /* + * return infinity + */ + Sgl_setinfinity_exponentmantissa(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 (Sgl_isinfinity_exponent(opnd2)) { + if (Sgl_iszero_mantissa(opnd2)) { + /* + * return zero + */ + Sgl_setzero_exponentmantissa(result); + *dstptr = result; + 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 for division by zero + */ + if (Sgl_iszero_exponentmantissa(opnd2)) { + if (Sgl_iszero_exponentmantissa(opnd1)) { + /* invalid since both operands are zero */ + if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(result); + *dstptr = result; + return(NOEXCEPTION); + } + if (Is_divisionbyzerotrap_enabled()) + return(DIVISIONBYZEROEXCEPTION); + Set_divisionbyzeroflag(); + Sgl_setinfinity_exponentmantissa(result); + *dstptr = result; + return(NOEXCEPTION); + } + /* + * Generate exponent + */ + dest_exponent = Sgl_exponent(opnd1) - Sgl_exponent(opnd2) + SGL_BIAS; + + /* + * Generate mantissa + */ + if (Sgl_isnotzero_exponent(opnd1)) { + /* set hidden bit */ + Sgl_clear_signexponent_set_hidden(opnd1); + } + else { + /* check for zero */ + if (Sgl_iszero_mantissa(opnd1)) { + Sgl_setzero_exponentmantissa(result); + *dstptr = result; + return(NOEXCEPTION); + } + /* is denormalized; want to normalize */ + Sgl_clear_signexponent(opnd1); + Sgl_leftshiftby1(opnd1); + Sgl_normalize(opnd1,dest_exponent); + } + /* opnd2 needs to have hidden bit set with msb in hidden bit */ + if (Sgl_isnotzero_exponent(opnd2)) { + Sgl_clear_signexponent_set_hidden(opnd2); + } + else { + /* is denormalized; want to normalize */ + Sgl_clear_signexponent(opnd2); + Sgl_leftshiftby1(opnd2); + while(Sgl_iszero_hiddenhigh7mantissa(opnd2)) { + Sgl_leftshiftby8(opnd2); + dest_exponent += 8; + } + if(Sgl_iszero_hiddenhigh3mantissa(opnd2)) { + Sgl_leftshiftby4(opnd2); + dest_exponent += 4; + } + while(Sgl_iszero_hidden(opnd2)) { + Sgl_leftshiftby1(opnd2); + dest_exponent += 1; + } + } + + /* Divide the source mantissas */ + + /* + * A non_restoring divide algorithm is used. + */ + Sgl_subtract(opnd1,opnd2,opnd1); + Sgl_setzero(opnd3); + for (count=1;count<=SGL_P && Sgl_all(opnd1);count++) { + Sgl_leftshiftby1(opnd1); + Sgl_leftshiftby1(opnd3); + if (Sgl_iszero_sign(opnd1)) { + Sgl_setone_lowmantissa(opnd3); + Sgl_subtract(opnd1,opnd2,opnd1); + } + else Sgl_addition(opnd1,opnd2,opnd1); + } + if (count <= SGL_P) { + Sgl_leftshiftby1(opnd3); + Sgl_setone_lowmantissa(opnd3); + Sgl_leftshift(opnd3,SGL_P-count); + if (Sgl_iszero_hidden(opnd3)) { + Sgl_leftshiftby1(opnd3); + dest_exponent--; + } + } + else { + if (Sgl_iszero_hidden(opnd3)) { + /* need to get one more bit of result */ + Sgl_leftshiftby1(opnd1); + Sgl_leftshiftby1(opnd3); + if (Sgl_iszero_sign(opnd1)) { + Sgl_setone_lowmantissa(opnd3); + Sgl_subtract(opnd1,opnd2,opnd1); + } + else Sgl_addition(opnd1,opnd2,opnd1); + dest_exponent--; + } + if (Sgl_iszero_sign(opnd1)) guardbit = TRUE; + stickybit = Sgl_all(opnd1); + } + inexact = guardbit | stickybit; + + /* + * round result + */ + if (inexact && (dest_exponent > 0 || Is_underflowtrap_enabled())) { + Sgl_clear_signexponent(opnd3); + switch (Rounding_mode()) { + case ROUNDPLUS: + if (Sgl_iszero_sign(result)) + Sgl_increment_mantissa(opnd3); + break; + case ROUNDMINUS: + if (Sgl_isone_sign(result)) + Sgl_increment_mantissa(opnd3); + break; + case ROUNDNEAREST: + if (guardbit) { + if (stickybit || Sgl_isone_lowmantissa(opnd3)) + Sgl_increment_mantissa(opnd3); + } + } + if (Sgl_isone_hidden(opnd3)) dest_exponent++; + } + Sgl_set_mantissa(result,opnd3); + + /* + * Test for overflow + */ + if (dest_exponent >= SGL_INFINITY_EXPONENT) { + /* trap if OVERFLOWTRAP enabled */ + if (Is_overflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Sgl_setwrapped_exponent(result,dest_exponent,ovfl); + *dstptr = result; + if (inexact) + if (Is_inexacttrap_enabled()) + return(OVERFLOWEXCEPTION | INEXACTEXCEPTION); + else Set_inexactflag(); + return(OVERFLOWEXCEPTION); + } + Set_overflowflag(); + /* set result to infinity or largest number */ + Sgl_setoverflow(result); + inexact = TRUE; + } + /* + * Test for underflow + */ + else 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; + 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 (Sgl_iszero_sign(result)) { + Sgl_increment(opnd3); + if (Sgl_isone_hiddenoverflow(opnd3)) + is_tiny = FALSE; + Sgl_decrement(opnd3); + } + break; + case ROUNDMINUS: + if (Sgl_isone_sign(result)) { + Sgl_increment(opnd3); + if (Sgl_isone_hiddenoverflow(opnd3)) + is_tiny = FALSE; + Sgl_decrement(opnd3); + } + break; + case ROUNDNEAREST: + if (guardbit && (stickybit || + Sgl_isone_lowmantissa(opnd3))) { + Sgl_increment(opnd3); + if (Sgl_isone_hiddenoverflow(opnd3)) + is_tiny = FALSE; + Sgl_decrement(opnd3); + } + break; + } + } + + /* + * denormalize result or set to signed zero + */ + stickybit = inexact; + Sgl_denormalize(opnd3,dest_exponent,guardbit,stickybit,inexact); + + /* return rounded number */ + if (inexact) { + switch (Rounding_mode()) { + case ROUNDPLUS: + if (Sgl_iszero_sign(result)) { + Sgl_increment(opnd3); + } + break; + case ROUNDMINUS: + if (Sgl_isone_sign(result)) { + Sgl_increment(opnd3); + } + break; + case ROUNDNEAREST: + if (guardbit && (stickybit || + Sgl_isone_lowmantissa(opnd3))) { + Sgl_increment(opnd3); + } + break; + } + if (is_tiny) Set_underflowflag(); + } + Sgl_set_exponentmantissa(result,opnd3); + } + else Sgl_set_exponent(result,dest_exponent); + *dstptr = result; + /* check for inexact */ + if (inexact) { + if (Is_inexacttrap_enabled()) return(INEXACTEXCEPTION); + else Set_inexactflag(); + } + return(NOEXCEPTION); +} |