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Diffstat (limited to '')
| -rw-r--r-- | arch/parisc/math-emu/sfrem.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/arch/parisc/math-emu/sfrem.c b/arch/parisc/math-emu/sfrem.c new file mode 100644 index 000000000..4ac88d829 --- /dev/null +++ b/arch/parisc/math-emu/sfrem.c @@ -0,0 +1,277 @@ +// 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/sfrem.c $Revision: 1.1 $ + * + * Purpose: + * Single Precision Floating-point Remainder + * + * External Interfaces: + * sgl_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 "sgl_float.h" + +/* + * Single Precision Floating-point Remainder + */ + +int +sgl_frem (sgl_floating_point * srcptr1, sgl_floating_point * srcptr2, + sgl_floating_point * dstptr, unsigned int *status) +{ + register unsigned int opnd1, opnd2, result; + register int opnd1_exponent, opnd2_exponent, dest_exponent, stepcount; + register boolean roundup = FALSE; + + opnd1 = *srcptr1; + opnd2 = *srcptr2; + /* + * check first operand for NaN's or infinity + */ + if ((opnd1_exponent = Sgl_exponent(opnd1)) == SGL_INFINITY_EXPONENT) { + if (Sgl_iszero_mantissa(opnd1)) { + if (Sgl_isnotnan(opnd2)) { + /* invalid since first operand is infinity */ + if (Is_invalidtrap_enabled()) + return(INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(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 ((opnd2_exponent = Sgl_exponent(opnd2)) == SGL_INFINITY_EXPONENT) { + if (Sgl_iszero_mantissa(opnd2)) { + /* + * return first operand + */ + *dstptr = opnd1; + 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 second operand for zero + */ + if (Sgl_iszero_exponentmantissa(opnd2)) { + /* invalid since second operand is zero */ + if (Is_invalidtrap_enabled()) return(INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(result); + *dstptr = result; + return(NOEXCEPTION); + } + + /* + * get sign of result + */ + result = opnd1; + + /* + * check for denormalized operands + */ + if (opnd1_exponent == 0) { + /* check for zero */ + if (Sgl_iszero_mantissa(opnd1)) { + *dstptr = opnd1; + return(NOEXCEPTION); + } + /* normalize, then continue */ + opnd1_exponent = 1; + Sgl_normalize(opnd1,opnd1_exponent); + } + else { + Sgl_clear_signexponent_set_hidden(opnd1); + } + if (opnd2_exponent == 0) { + /* normalize, then continue */ + opnd2_exponent = 1; + Sgl_normalize(opnd2,opnd2_exponent); + } + else { + Sgl_clear_signexponent_set_hidden(opnd2); + } + + /* 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 && Sgl_isgreaterthan(opnd1,opnd2)) { + Sgl_all(result) = ~Sgl_all(result); /* set sign */ + /* align opnd2 with opnd1 */ + Sgl_leftshiftby1(opnd2); + Sgl_subtract(opnd2,opnd1,opnd2); + /* now normalize */ + while (Sgl_iszero_hidden(opnd2)) { + Sgl_leftshiftby1(opnd2); + dest_exponent--; + } + Sgl_set_exponentmantissa(result,opnd2); + goto testforunderflow; + } + /* + * opnd1/opnd2 <= 1/2 + * + * In this case n will round to zero, so + * r = opnd1 + */ + Sgl_set_exponentmantissa(result,opnd1); + dest_exponent = opnd1_exponent; + goto testforunderflow; + } + + /* + * Generate result + * + * Do iterative subtract until remainder is less than operand 2. + */ + while (stepcount-- > 0 && Sgl_all(opnd1)) { + if (Sgl_isnotlessthan(opnd1,opnd2)) + Sgl_subtract(opnd1,opnd2,opnd1); + Sgl_leftshiftby1(opnd1); + } + /* + * Do last subtract, then determine which way to round if remainder + * is exactly 1/2 of opnd2 + */ + if (Sgl_isnotlessthan(opnd1,opnd2)) { + Sgl_subtract(opnd1,opnd2,opnd1); + roundup = TRUE; + } + if (stepcount > 0 || Sgl_iszero(opnd1)) { + /* division is exact, remainder is zero */ + Sgl_setzero_exponentmantissa(result); + *dstptr = result; + 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. + */ + Sgl_leftshiftby1(opnd1); + if (Sgl_isgreaterthan(opnd1,opnd2)) { + Sgl_invert_sign(result); + Sgl_subtract((opnd2<<1),opnd1,opnd1); + } + /* check for remainder being exactly 1/2 of opnd2 */ + else if (Sgl_isequal(opnd1,opnd2) && roundup) { + Sgl_invert_sign(result); + } + + /* normalize result's mantissa */ + while (Sgl_iszero_hidden(opnd1)) { + dest_exponent--; + Sgl_leftshiftby1(opnd1); + } + Sgl_set_exponentmantissa(result,opnd1); + + /* + * Test for underflow + */ + testforunderflow: + 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; + /* frem is always exact */ + return(UNDERFLOWEXCEPTION); + } + /* + * denormalize result or set to signed zero + */ + if (dest_exponent >= (1 - SGL_P)) { + Sgl_rightshift_exponentmantissa(result,1-dest_exponent); + } + else { + Sgl_setzero_exponentmantissa(result); + } + } + else Sgl_set_exponent(result,dest_exponent); + *dstptr = result; + return(NOEXCEPTION); +} |