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/* This is a software decimal floating point library. Copyright (C) 2005-2022 Free Software Foundation, Inc.
This file is part of GCC.
GCC 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 3, or (at your option) any later version.
GCC 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.
Under Section 7 of GPL version 3, you are granted additional permissions described in the GCC Runtime Library Exception, version 3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and a copy of the GCC Runtime Library Exception along with this program; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see <http://www.gnu.org/licenses/>. */
/* This implements IEEE 754 decimal floating point arithmetic, but does not provide a mechanism for setting the rounding mode, or for generating or handling exceptions. Conversions between decimal floating point types and other types depend on C library functions.
Contributed by Ben Elliston <bje@au.ibm.com>. */
#include <stdio.h> #include <stdlib.h> /* FIXME: compile with -std=gnu99 to get these from stdlib.h */ extern float strtof (const char *, char **); extern long double strtold (const char *, char **); #include <string.h> #include <limits.h>
#include "dfp-bit.h"
/* Forward declarations. */ #if WIDTH == 32 || WIDTH_TO == 32 void __host_to_ieee_32 (_Decimal32 in, decimal32 *out); void __ieee_to_host_32 (decimal32 in, _Decimal32 *out); #endif #if WIDTH == 64 || WIDTH_TO == 64 void __host_to_ieee_64 (_Decimal64 in, decimal64 *out); void __ieee_to_host_64 (decimal64 in, _Decimal64 *out); #endif #if WIDTH == 128 || WIDTH_TO == 128 void __host_to_ieee_128 (_Decimal128 in, decimal128 *out); void __ieee_to_host_128 (decimal128 in, _Decimal128 *out); #endif
/* A pointer to a binary decFloat operation. */ typedef decFloat* (*dfp_binary_func) (decFloat *, const decFloat *, const decFloat *, decContext *);
/* Binary operations. */
/* Use a decFloat (decDouble or decQuad) function to perform a DFP binary operation. */ static inline decFloat dfp_binary_op (dfp_binary_func op, decFloat arg_a, decFloat arg_b) { decFloat result; decContext context;
decContextDefault (&context, CONTEXT_INIT); DFP_INIT_ROUNDMODE (context.round);
/* Perform the operation. */ op (&result, &arg_a, &arg_b, &context);
if (DFP_EXCEPTIONS_ENABLED && context.status != 0) { /* decNumber exception flags we care about here. */ int ieee_flags; int dec_flags = DEC_IEEE_854_Division_by_zero | DEC_IEEE_854_Inexact | DEC_IEEE_854_Invalid_operation | DEC_IEEE_854_Overflow | DEC_IEEE_854_Underflow; dec_flags &= context.status; ieee_flags = DFP_IEEE_FLAGS (dec_flags); if (ieee_flags != 0) DFP_HANDLE_EXCEPTIONS (ieee_flags); }
return result; }
#if WIDTH == 32 /* The decNumber package doesn't provide arithmetic for decSingle (32 bits); convert to decDouble, use the operation for that, and convert back. */ static inline _Decimal32 d32_binary_op (dfp_binary_func op, _Decimal32 arg_a, _Decimal32 arg_b) { union { _Decimal32 c; decSingle f; } a32, b32, res32; decDouble a, b, res; decContext context;
/* Widen the operands and perform the operation. */ a32.c = arg_a; b32.c = arg_b; decSingleToWider (&a32.f, &a); decSingleToWider (&b32.f, &b); res = dfp_binary_op (op, a, b);
/* Narrow the result, which might result in an underflow or overflow. */ decContextDefault (&context, CONTEXT_INIT); DFP_INIT_ROUNDMODE (context.round); decSingleFromWider (&res32.f, &res, &context); if (DFP_EXCEPTIONS_ENABLED && context.status != 0) { /* decNumber exception flags we care about here. */ int ieee_flags; int dec_flags = DEC_IEEE_854_Inexact | DEC_IEEE_854_Overflow | DEC_IEEE_854_Underflow; dec_flags &= context.status; ieee_flags = DFP_IEEE_FLAGS (dec_flags); if (ieee_flags != 0) DFP_HANDLE_EXCEPTIONS (ieee_flags); }
return res32.c; } #else /* decFloat operations are supported for decDouble (64 bits) and decQuad (128 bits). The bit patterns for the types are the same. */ static inline DFP_C_TYPE dnn_binary_op (dfp_binary_func op, DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { union { DFP_C_TYPE c; decFloat f; } a, b, result;
a.c = arg_a; b.c = arg_b; result.f = dfp_binary_op (op, a.f, b.f); return result.c; } #endif
/* Comparison operations. */
/* Use a decFloat (decDouble or decQuad) function to perform a DFP comparison. */ static inline CMPtype dfp_compare_op (dfp_binary_func op, decFloat arg_a, decFloat arg_b) { decContext context; decFloat res; int result;
decContextDefault (&context, CONTEXT_INIT); DFP_INIT_ROUNDMODE (context.round);
/* Perform the comparison. */ op (&res, &arg_a, &arg_b, &context);
if (DEC_FLOAT_IS_SIGNED (&res)) result = -1; else if (DEC_FLOAT_IS_ZERO (&res)) result = 0; else if (DEC_FLOAT_IS_NAN (&res)) result = -2; else result = 1;
return (CMPtype) result; }
#if WIDTH == 32 /* The decNumber package doesn't provide comparisons for decSingle (32 bits); convert to decDouble, use the operation for that, and convert back. */ static inline CMPtype d32_compare_op (dfp_binary_func op, _Decimal32 arg_a, _Decimal32 arg_b) { union { _Decimal32 c; decSingle f; } a32, b32; decDouble a, b;
a32.c = arg_a; b32.c = arg_b; decSingleToWider (&a32.f, &a); decSingleToWider (&b32.f, &b); return dfp_compare_op (op, a, b); } #else /* decFloat comparisons are supported for decDouble (64 bits) and decQuad (128 bits). The bit patterns for the types are the same. */ static inline CMPtype dnn_compare_op (dfp_binary_func op, DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { union { DFP_C_TYPE c; decFloat f; } a, b;
a.c = arg_a; b.c = arg_b; return dfp_compare_op (op, a.f, b.f); } #endif
#if defined(L_conv_sd) void __host_to_ieee_32 (_Decimal32 in, decimal32 *out) { memcpy (out, &in, 4); }
void __ieee_to_host_32 (decimal32 in, _Decimal32 *out) { memcpy (out, &in, 4); } #endif /* L_conv_sd */
#if defined(L_conv_dd) void __host_to_ieee_64 (_Decimal64 in, decimal64 *out) { memcpy (out, &in, 8); }
void __ieee_to_host_64 (decimal64 in, _Decimal64 *out) { memcpy (out, &in, 8); } #endif /* L_conv_dd */
#if defined(L_conv_td) void __host_to_ieee_128 (_Decimal128 in, decimal128 *out) { memcpy (out, &in, 16); }
void __ieee_to_host_128 (decimal128 in, _Decimal128 *out) { memcpy (out, &in, 16); } #endif /* L_conv_td */
#if defined(L_addsub_sd) || defined(L_addsub_dd) || defined(L_addsub_td) DFP_C_TYPE DFP_ADD (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { return DFP_BINARY_OP (DEC_FLOAT_ADD, arg_a, arg_b); }
DFP_C_TYPE DFP_SUB (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { return DFP_BINARY_OP (DEC_FLOAT_SUBTRACT, arg_a, arg_b); } #endif /* L_addsub */
#if defined(L_mul_sd) || defined(L_mul_dd) || defined(L_mul_td) DFP_C_TYPE DFP_MULTIPLY (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { return DFP_BINARY_OP (DEC_FLOAT_MULTIPLY, arg_a, arg_b); } #endif /* L_mul */
#if defined(L_div_sd) || defined(L_div_dd) || defined(L_div_td) DFP_C_TYPE DFP_DIVIDE (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { return DFP_BINARY_OP (DEC_FLOAT_DIVIDE, arg_a, arg_b); } #endif /* L_div */
#if defined (L_eq_sd) || defined (L_eq_dd) || defined (L_eq_td) CMPtype DFP_EQ (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { CMPtype stat; stat = DFP_COMPARE_OP (DEC_FLOAT_COMPARE, arg_a, arg_b); /* For EQ return zero for true, nonzero for false. */ return stat != 0; } #endif /* L_eq */
#if defined (L_ne_sd) || defined (L_ne_dd) || defined (L_ne_td) CMPtype DFP_NE (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { int stat; stat = DFP_COMPARE_OP (DEC_FLOAT_COMPARE, arg_a, arg_b); /* For NE return zero for true, nonzero for false. */ if (__builtin_expect (stat == -2, 0)) /* An operand is NaN. */ return 1; return stat != 0; } #endif /* L_ne */
#if defined (L_lt_sd) || defined (L_lt_dd) || defined (L_lt_td) CMPtype DFP_LT (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { int stat; stat = DFP_COMPARE_OP (DEC_FLOAT_COMPARE, arg_a, arg_b); /* For LT return -1 (<0) for true, 1 for false. */ return (stat == -1) ? -1 : 1; } #endif /* L_lt */
#if defined (L_gt_sd) || defined (L_gt_dd) || defined (L_gt_td) CMPtype DFP_GT (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { int stat; stat = DFP_COMPARE_OP (DEC_FLOAT_COMPARE, arg_a, arg_b); /* For GT return 1 (>0) for true, -1 for false. */ return (stat == 1) ? 1 : -1; } #endif
#if defined (L_le_sd) || defined (L_le_dd) || defined (L_le_td) CMPtype DFP_LE (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { int stat; stat = DFP_COMPARE_OP (DEC_FLOAT_COMPARE, arg_a, arg_b); /* For LE return 0 (<= 0) for true, 1 for false. */ if (__builtin_expect (stat == -2, 0)) /* An operand is NaN. */ return 1; return stat == 1; } #endif /* L_le */
#if defined (L_ge_sd) || defined (L_ge_dd) || defined (L_ge_td) CMPtype DFP_GE (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { int stat; stat = DFP_COMPARE_OP (DEC_FLOAT_COMPARE, arg_a, arg_b); /* For GE return 1 (>=0) for true, -1 for false. */ if (__builtin_expect (stat == -2, 0)) /* An operand is NaN. */ return -1; return (stat != -1) ? 1 : -1; } #endif /* L_ge */
#define BUFMAX 128
/* Check for floating point exceptions that are relevant for conversions between decimal float values and handle them. */ static inline void dfp_conversion_exceptions (const int status) { /* decNumber exception flags we care about here. */ int ieee_flags; int dec_flags = DEC_IEEE_854_Inexact | DEC_IEEE_854_Invalid_operation | DEC_IEEE_854_Overflow; dec_flags &= status; ieee_flags = DFP_IEEE_FLAGS (dec_flags); if (ieee_flags != 0) DFP_HANDLE_EXCEPTIONS (ieee_flags); }
#if defined (L_sd_to_dd) /* Use decNumber to convert directly from _Decimal32 to _Decimal64. */ _Decimal64 DFP_TO_DFP (_Decimal32 f_from) { union { _Decimal32 c; decSingle f; } from; union { _Decimal64 c; decDouble f; } to;
from.c = f_from; to.f = *decSingleToWider (&from.f, &to.f); return to.c; } #endif
#if defined (L_sd_to_td) /* Use decNumber to convert directly from _Decimal32 to _Decimal128. */ _Decimal128 DFP_TO_DFP (_Decimal32 f_from) { union { _Decimal32 c; decSingle f; } from; union { _Decimal128 c; decQuad f; } to; decDouble temp;
from.c = f_from; temp = *decSingleToWider (&from.f, &temp); to.f = *decDoubleToWider (&temp, &to.f); return to.c; } #endif
#if defined (L_dd_to_td) /* Use decNumber to convert directly from _Decimal64 to _Decimal128. */ _Decimal128 DFP_TO_DFP (_Decimal64 f_from) { union { _Decimal64 c; decDouble f; } from; union { _Decimal128 c; decQuad f; } to;
from.c = f_from; to.f = *decDoubleToWider (&from.f, &to.f); return to.c; } #endif
#if defined (L_dd_to_sd) /* Use decNumber to convert directly from _Decimal64 to _Decimal32. */ _Decimal32 DFP_TO_DFP (_Decimal64 f_from) { union { _Decimal32 c; decSingle f; } to; union { _Decimal64 c; decDouble f; } from; decContext context;
decContextDefault (&context, CONTEXT_INIT); DFP_INIT_ROUNDMODE (context.round); from.c = f_from; to.f = *decSingleFromWider (&to.f, &from.f, &context); if (DFP_EXCEPTIONS_ENABLED && context.status != 0) dfp_conversion_exceptions (context.status); return to.c; } #endif
#if defined (L_td_to_sd) /* Use decNumber to convert directly from _Decimal128 to _Decimal32. */ _Decimal32 DFP_TO_DFP (_Decimal128 f_from) { union { _Decimal32 c; decSingle f; } to; union { _Decimal128 c; decQuad f; } from; decDouble temp; decContext context;
decContextDefault (&context, CONTEXT_INIT); DFP_INIT_ROUNDMODE (context.round); from.c = f_from; temp = *decDoubleFromWider (&temp, &from.f, &context); to.f = *decSingleFromWider (&to.f, &temp, &context); if (DFP_EXCEPTIONS_ENABLED && context.status != 0) dfp_conversion_exceptions (context.status); return to.c; } #endif
#if defined (L_td_to_dd) /* Use decNumber to convert directly from _Decimal128 to _Decimal64. */ _Decimal64 DFP_TO_DFP (_Decimal128 f_from) { union { _Decimal64 c; decDouble f; } to; union { _Decimal128 c; decQuad f; } from; decContext context;
decContextDefault (&context, CONTEXT_INIT); DFP_INIT_ROUNDMODE (context.round); from.c = f_from; to.f = *decDoubleFromWider (&to.f, &from.f, &context); if (DFP_EXCEPTIONS_ENABLED && context.status != 0) dfp_conversion_exceptions (context.status); return to.c; } #endif
#if defined (L_dd_to_si) || defined (L_td_to_si) \ || defined (L_dd_to_usi) || defined (L_td_to_usi) /* Use decNumber to convert directly from decimal float to integer types. */ INT_TYPE DFP_TO_INT (DFP_C_TYPE x) { union { DFP_C_TYPE c; decFloat f; } u; decContext context; INT_TYPE i;
decContextDefault (&context, DEC_INIT_DECIMAL128); context.round = DEC_ROUND_DOWN; u.c = x; i = DEC_FLOAT_TO_INT (&u.f, &context, context.round); if (DFP_EXCEPTIONS_ENABLED && context.status != 0) dfp_conversion_exceptions (context.status); return i; } #endif
#if defined (L_sd_to_si) || (L_sd_to_usi) /* Use decNumber to convert directly from decimal float to integer types. */ INT_TYPE DFP_TO_INT (_Decimal32 x) { union { _Decimal32 c; decSingle f; } u32; decDouble f64; decContext context; INT_TYPE i;
decContextDefault (&context, DEC_INIT_DECIMAL128); context.round = DEC_ROUND_DOWN; u32.c = x; f64 = *decSingleToWider (&u32.f, &f64); i = DEC_FLOAT_TO_INT (&f64, &context, context.round); if (DFP_EXCEPTIONS_ENABLED && context.status != 0) dfp_conversion_exceptions (context.status); return i; } #endif
#if defined (L_sd_to_di) || defined (L_dd_to_di) || defined (L_td_to_di) \ || defined (L_sd_to_udi) || defined (L_dd_to_udi) || defined (L_td_to_udi) /* decNumber doesn't provide support for conversions to 64-bit integer types, so do it the hard way. */ INT_TYPE DFP_TO_INT (DFP_C_TYPE x) { /* decNumber's decimal* types have the same format as C's _Decimal* types, but they have different calling conventions. */
/* TODO: Decimal float to integer conversions should raise FE_INVALID if the result value does not fit into the result type. */
IEEE_TYPE s; char buf[BUFMAX]; char *pos; decNumber qval, n1, n2; decContext context;
/* Use a large context to avoid losing precision. */ decContextDefault (&context, DEC_INIT_DECIMAL128); /* Need non-default rounding mode here. */ context.round = DEC_ROUND_DOWN;
HOST_TO_IEEE (x, &s); TO_INTERNAL (&s, &n1); /* Rescale if the exponent is less than zero. */ decNumberToIntegralValue (&n2, &n1, &context); /* Get a value to use for the quantize call. */ decNumberFromString (&qval, "1.", &context); /* Force the exponent to zero. */ decNumberQuantize (&n1, &n2, &qval, &context); /* Get a string, which at this point will not include an exponent. */ decNumberToString (&n1, buf); /* Ignore the fractional part. */ pos = strchr (buf, '.'); if (pos) *pos = 0; /* Use a C library function to convert to the integral type. */ return STR_TO_INT (buf, NULL, 10); } #endif
#if defined (L_si_to_dd) || defined (L_si_to_td) \ || defined (L_usi_to_dd) || defined (L_usi_to_td) /* Use decNumber to convert directly from integer to decimal float types. */ DFP_C_TYPE INT_TO_DFP (INT_TYPE i) { union { DFP_C_TYPE c; decFloat f; } u;
u.f = *DEC_FLOAT_FROM_INT (&u.f, i); return u.c; } #endif
#if defined (L_si_to_sd) || defined (L_usi_to_sd) _Decimal32 /* Use decNumber to convert directly from integer to decimal float types. */ INT_TO_DFP (INT_TYPE i) { union { _Decimal32 c; decSingle f; } u32; decDouble f64; decContext context;
decContextDefault (&context, DEC_INIT_DECIMAL128); f64 = *DEC_FLOAT_FROM_INT (&f64, i); u32.f = *decSingleFromWider (&u32.f, &f64, &context); if (DFP_EXCEPTIONS_ENABLED && context.status != 0) dfp_conversion_exceptions (context.status); return u32.c; } #endif
#if defined (L_di_to_sd) || defined (L_di_to_dd) || defined (L_di_to_td) \ || defined (L_udi_to_sd) || defined (L_udi_to_dd) || defined (L_udi_to_td) /* decNumber doesn't provide support for conversions from 64-bit integer types, so do it the hard way. */ DFP_C_TYPE INT_TO_DFP (INT_TYPE i) { DFP_C_TYPE f; IEEE_TYPE s; char buf[BUFMAX]; decContext context;
decContextDefault (&context, CONTEXT_INIT); DFP_INIT_ROUNDMODE (context.round);
/* Use a C library function to get a floating point string. */ sprintf (buf, INT_FMT ".", CAST_FOR_FMT(i)); /* Convert from the floating point string to a decimal* type. */ FROM_STRING (&s, buf, &context); IEEE_TO_HOST (s, &f);
if (DFP_EXCEPTIONS_ENABLED && context.status != 0) dfp_conversion_exceptions (context.status);
return f; } #endif
#if defined (L_sd_to_sf) || defined (L_dd_to_sf) || defined (L_td_to_sf) \ || defined (L_sd_to_df) || defined (L_dd_to_df) || defined (L_td_to_df) \ || defined (L_sd_to_kf) || defined (L_dd_to_kf) || defined (L_td_to_kf) \ || ((defined (L_sd_to_xf) || defined (L_dd_to_xf) || defined (L_td_to_xf)) \ && LONG_DOUBLE_HAS_XF_MODE) \ || ((defined (L_sd_to_tf) || defined (L_dd_to_tf) || defined (L_td_to_tf)) \ && LONG_DOUBLE_HAS_TF_MODE) BFP_TYPE DFP_TO_BFP (DFP_C_TYPE f) { IEEE_TYPE s; char buf[BUFMAX];
HOST_TO_IEEE (f, &s); /* Write the value to a string. */ TO_STRING (&s, buf); /* Read it as the binary floating point type and return that. */ return STR_TO_BFP (buf, NULL); } #endif #if defined (L_sf_to_sd) || defined (L_sf_to_dd) || defined (L_sf_to_td) \ || defined (L_df_to_sd) || defined (L_df_to_dd) || defined (L_df_to_td) \ || defined (L_kf_to_sd) || defined (L_kf_to_dd) || defined (L_kf_to_td) \ || ((defined (L_xf_to_sd) || defined (L_xf_to_dd) || defined (L_xf_to_td)) \ && LONG_DOUBLE_HAS_XF_MODE) \ || ((defined (L_tf_to_sd) || defined (L_tf_to_dd) || defined (L_tf_to_td)) \ && LONG_DOUBLE_HAS_TF_MODE) DFP_C_TYPE BFP_TO_DFP (BFP_TYPE x) { DFP_C_TYPE f; IEEE_TYPE s; char buf[BUFMAX]; decContext context;
decContextDefault (&context, CONTEXT_INIT); DFP_INIT_ROUNDMODE (context.round);
/* Use the sprintf library function to write the floating point value to a string.
If we are handling the IEEE 128-bit floating point on PowerPC, use the special function __sprintfkf instead of sprintf. This function allows us to use __sprintfieee128 if we have a new enough GLIBC, and it can fall back to using the traditional sprintf via conversion to IBM 128-bit if the glibc is older. */ BFP_SPRINTF (buf, BFP_FMT, (BFP_VIA_TYPE) x);
/* Convert from the floating point string to a decimal* type. */ FROM_STRING (&s, buf, &context); IEEE_TO_HOST (s, &f);
if (DFP_EXCEPTIONS_ENABLED && context.status != 0) { /* decNumber exception flags we care about here. */ int ieee_flags; int dec_flags = DEC_IEEE_854_Inexact | DEC_IEEE_854_Invalid_operation | DEC_IEEE_854_Overflow | DEC_IEEE_854_Underflow; dec_flags &= context.status; ieee_flags = DFP_IEEE_FLAGS (dec_flags); if (ieee_flags != 0) DFP_HANDLE_EXCEPTIONS (ieee_flags); }
return f; } #endif
#if defined (L_unord_sd) || defined (L_unord_dd) || defined (L_unord_td) CMPtype DFP_UNORD (DFP_C_TYPE arg_a, DFP_C_TYPE arg_b) { decNumber arg1, arg2; IEEE_TYPE a, b;
HOST_TO_IEEE (arg_a, &a); HOST_TO_IEEE (arg_b, &b); TO_INTERNAL (&a, &arg1); TO_INTERNAL (&b, &arg2); return (decNumberIsNaN (&arg1) || decNumberIsNaN (&arg2)); } #endif /* L_unord_sd || L_unord_dd || L_unord_td */
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