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Diffstat (limited to '')
| -rw-r--r-- | arch/parisc/math-emu/sfmpy.c | 367 |
1 files changed, 367 insertions, 0 deletions
diff --git a/arch/parisc/math-emu/sfmpy.c b/arch/parisc/math-emu/sfmpy.c new file mode 100644 index 000000000..7f4518679 --- /dev/null +++ b/arch/parisc/math-emu/sfmpy.c @@ -0,0 +1,367 @@ +// 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/sfmpy.c $Revision: 1.1 $ + * + * Purpose: + * Single Precision Floating-point Multiply + * + * External Interfaces: + * sgl_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 "sgl_float.h" + +/* + * Single Precision Floating-point Multiply + */ + +int +sgl_fmpy( + 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_iszero_exponentmantissa(opnd2)) { + /* + * invalid since operands are infinity + * and zero + */ + 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)) { + if (Sgl_iszero_exponentmantissa(opnd1)) { + /* invalid since operands are zero & infinity */ + if (Is_invalidtrap_enabled()) + return(INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(opnd2); + *dstptr = opnd2; + return(NOEXCEPTION); + } + /* + * return infinity + */ + Sgl_setinfinity_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); + } + /* + * 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, adjust exponent */ + 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 { + /* check for zero */ + if (Sgl_iszero_mantissa(opnd2)) { + Sgl_setzero_exponentmantissa(result); + *dstptr = result; + return(NOEXCEPTION); + } + /* is denormalized; want to normalize */ + Sgl_clear_signexponent(opnd2); + Sgl_leftshiftby1(opnd2); + Sgl_normalize(opnd2,dest_exponent); + } + + /* Multiply two source mantissas together */ + + Sgl_leftshiftby4(opnd2); /* make room for guard bits */ + Sgl_setzero(opnd3); + /* + * Four bits at a time are inspected in each loop, and a + * simple shift and add multiply algorithm is used. + */ + for (count=1;count<SGL_P;count+=4) { + stickybit |= Slow4(opnd3); + Sgl_rightshiftby4(opnd3); + if (Sbit28(opnd1)) Sall(opnd3) += (Sall(opnd2) << 3); + if (Sbit29(opnd1)) Sall(opnd3) += (Sall(opnd2) << 2); + if (Sbit30(opnd1)) Sall(opnd3) += (Sall(opnd2) << 1); + if (Sbit31(opnd1)) Sall(opnd3) += Sall(opnd2); + Sgl_rightshiftby4(opnd1); + } + /* make sure result is left-justified */ + if (Sgl_iszero_sign(opnd3)) { + Sgl_leftshiftby1(opnd3); + } + else { + /* result mantissa >= 2. */ + dest_exponent++; + } + /* check for denormalized result */ + while (Sgl_iszero_sign(opnd3)) { + Sgl_leftshiftby1(opnd3); + dest_exponent--; + } + /* + * check for guard, sticky and inexact bits + */ + stickybit |= Sgl_all(opnd3) << (SGL_BITLENGTH - SGL_EXP_LENGTH + 1); + guardbit = Sbit24(opnd3); + inexact = guardbit | stickybit; + + /* re-align mantissa */ + Sgl_rightshiftby8(opnd3); + + /* + * 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(opnd3); + break; + case ROUNDMINUS: + if (Sgl_isone_sign(result)) + Sgl_increment(opnd3); + break; + case ROUNDNEAREST: + if (guardbit) { + if (stickybit || Sgl_isone_lowmantissa(opnd3)) + Sgl_increment(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); + } + inexact = TRUE; + Set_overflowflag(); + /* set result to infinity or largest number */ + Sgl_setoverflow(result); + } + /* + * 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 zero or smallest 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); +} |