bdldfp_decimalplatform.h

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/// @file bdldfp_decimalplatform.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bdldfp_decimalplatform.h                                           -*-C++-*-
#ifndef INCLUDED_BDLDFP_DECIMALPLATFORM
#define INCLUDED_BDLDFP_DECIMALPLATFORM
 
#include <bsls_ident.h>
BSLS_IDENT("$Id$")
 
/// @defgroup bdldfp_decimalplatform bdldfp_decimalplatform
/// @brief  Provide decimal floating-point platform information macros.
/// @addtogroup bdl
/// @{
/// @addtogroup bdldfp
/// @{
/// @addtogroup bdldfp_decimalplatform
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bdldfp_decimalplatform-purpose"> Purpose</a>
/// * <a href="#bdldfp_decimalplatform-macros"> Macros </a>
/// * <a href="#bdldfp_decimalplatform-description"> Description </a>
///   * <a href="#bdldfp_decimalplatform-macros-defining-the-underlying-implementation"> Macros Defining the Underlying Implementation </a>
///   * <a href="#bdldfp_decimalplatform-macros-defining-hardware-support-vs-software-emulation"> Macros Defining Hardware Support vs. Software Emulation </a>
///   * <a href="#bdldfp_decimalplatform-endianness"> Endianness </a>
///   * <a href="#bdldfp_decimalplatform-encoding"> Encoding </a>
///   * <a href="#bdldfp_decimalplatform-implementation-detail-macros"> Implementation Detail Macros </a>
///   * <a href="#bdldfp_decimalplatform-usage"> Usage </a>
///
/// # Purpose {#bdldfp_decimalplatform-purpose}
/// Provide decimal floating-point platform information macros.
///
/// # Macros {#bdldfp_decimalplatform-macros}
///
/// -  BDLDFP_DECIMALPLATFORM_C99_TR: using C99 (C-language) decimal fp support
/// -  BDLDFP_DECIMALPLATFORM_INTELDFP: using the `IntelDFP` library
/// -  BDLDFP_DECIMALPLATFORM_HARDWARE: using hardware support for decimals
/// -  BDLDFP_DECIMALPLATFORM_SOFTWARE: using software only (no hardware support)
/// -  BDLDFP_DECIMALPLATFORM_BIG_ENDIAN: decimals are big endian
/// -  BDLDFP_DECIMALPLATFORM_LITTLE_ENDIAN: decimals are little endian
/// -  BDLDFP_DECIMALPLATFORM_DPD: using densely packed decimal representation
/// -  BDLDFP_DECIMALPLATFORM_BININT: binary integer significand representation
/// -  BDLDFP_DECIMALPLATFORM_SNPRINTF_BUFFER_SIZE: internal use only (remove)
/// -  BDLDFP_DECIMALPLATFORM_C99_QNAN*: internal use only, will be removed
/// -  BDLDFP_DECIMALPLATFORM_C99_SNAN*: internal use only, will be removed
///
/// @see  bdldfp_decimal, bdldfp_decimalutil, bdldfp_decimalconvertutil
///
/// # Description {#bdldfp_decimalplatform-description}
/// This component provides a suite of preprocessor macros that
/// identify and define platform-specific compile-time attributes that are
/// related to decimal floating-point support.  The macros provided by this
/// component are defined to the be non-zero (true) when enabled on a given
/// platform, and are undefined on platforms where they are not enabled.  Some
/// macros are implentation details, providing platform-specific information
/// that is not useful outside of the BDE implementation.
///
/// ## Macros Defining the Underlying Implementation {#bdldfp_decimalplatform-macros-defining-the-underlying-implementation}
///
///
/// Only one of these macros will be defined any supported platform:
///
/// `BDLDFP_DECIMALPLATFORM_C99_TR` - Full ISO/IEC TR 24732 support with
///                                   library.
///
/// `BDLDFP_DECIMALPLATFORM_INTELDFP` - Using bdl+inteldfp as emulation
///
/// ## Macros Defining Hardware Support vs. Software Emulation {#bdldfp_decimalplatform-macros-defining-hardware-support-vs-software-emulation}
///
///
/// Only one of these macros will be defined on any supported platform:
///
/// `BDLDFP_DECIMALPLATFORM_HARDWARE` - Hardware support for at least one type.
///
/// `BDLDFP_DECIMALPLATFORM_SOFTWARE` - Software emulation for all types
///
/// ## Endianness {#bdldfp_decimalplatform-endianness}
///
///
/// There is a chance that the endianness of integers and decimal floating
/// point are not the same as those of integers; therefore we provide two
/// macros here to support implementation of endianness conversions.
///
/// `BDLDFP_DECIMALPLATFORM_BIG_ENDIAN` - big endian storage
///
/// `BDLDFP_DECIMALPLATFORM_LITTLE_ENDIAN` - little endian storage
///
/// ## Encoding {#bdldfp_decimalplatform-encoding}
///
///
/// There are two IEEE-754 sanctioned encodings for the significand: densely
/// packed decimal and binary integer significand.  We provide two macros here
/// to support implementation of encoding conversions.
///
/// `BDLDFP_DECIMALPLATFORM_DPD` - Densely Packed Decimal significand
///                                representation
///
/// `BDLDFP_DECIMALPLATFORM_BININT` - Binary Integer significand representation
///
/// ## Implementation Detail Macros {#bdldfp_decimalplatform-implementation-detail-macros}
///
///
/// These macros may or may not be present, depending on the platform.  They are
/// not meant for use outside of the Decimal Floating Point implementation;
/// Therefore using them in your code will result in undefined behavior.
///
/// `BDLDFP_DECIMALPLATFORM_SNPRINTF_BUFFER_SIZE` - max chars to print Dec128
///
/// `BDLDFP_DECIMALPLATFORM_C99_QNAN32` - The expression to get a quiet NaN of
/// `BDLDFP_DECIMALPLATFORM_C99_QNAN64`   the type the number postfix refers to.
/// `BDLDFP_DECIMALPLATFORM_C99_QNAN128`
///
/// `BDLDFP_DECIMALPLATFORM_C99_SNAN32` - The expression to get a signaling NaN
/// `BDLDFP_DECIMALPLATFORM_C99_SNAN64`   of the type the number postfix refers
/// `BDLDFP_DECIMALPLATFORM_C99_SNAN128`  to.
///
/// ## Usage {#bdldfp_decimalplatform-usage}
///
///
/// In this section, we show the intended usage of this component.
/// @code
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bdl
 * @{
 */
/** @addtogroup bdldfp
 * @{
 */
/** @addtogroup bdldfp_decimalplatform
 * @{
 */
 
#include <bdlscm_version.h>
 
#include <bsls_platform.h>
 
#include <bslmf_assert.h>
 
// C99 decimal support on xlC/Aix issues should be resolved (see
// DRQS 39471014).
 
 
// We have decided to disable IBM hardware floating point, at this time.
 
#if 0 && defined(BSLS_PLATFORM_CMP_IBM) && defined(__IBM_DFP__) && __IBM_DFP__
 
 
#  define BDLDFP_DECIMALPLATFORM_C99_QNAN32  __d32_qNaN()
#  define BDLDFP_DECIMALPLATFORM_C99_QNAN64  __d64_qNaN()
#  define BDLDFP_DECIMALPLATFORM_C99_QNAN128 __d128_qNaN()
#  define BDLDFP_DECIMALPLATFORM_C99_SNAN32  __d32_sNaN()
#  define BDLDFP_DECIMALPLATFORM_C99_SNAN64  __d64_sNaN()
#  define BDLDFP_DECIMALPLATFORM_C99_SNAN128 __d128_sNaN()
 
#  define BDLDFP_DECIMALPLATFORM_C99_NO_FMAD64 1
 
#  if defined(__IBM_DFP_SW_EMULATION__) && __IBM_DFP_SW_EMULATION__
#    define BDLDFP_DECIMALPLATFORM_SOFTWARE 1
#  else
#    define BDLDFP_DECIMALPLATFORM_HARDWARE 1
#  endif
#  define BDLDFP_DECIMALPLATFORM_C99_TR   1
#else
#  define BDLDFP_DECIMALPLATFORM_SOFTWARE 1
#endif
 
// TODO: a rough hack -- fix this.
 
#  define BDLDFP_DECIMALPLATFORM_SNPRINTF_BUFFER_SIZE 256
 
#ifndef BDLDFP_DECIMALPLATFORM_C99_TR
#  if 1
#    define BDLDFP_DECIMALPLATFORM_INTELDFP  1
#  endif
#endif
 
#ifdef BDLDFP_DECIMALPLATFORM_C99_TR
#  define BDLDFP_DECIMALPLATFORM_DPD    1
#elif defined(BDLDFP_DECIMALPLATFORM_INTELDFP)
#  define BDLDFP_DECIMALPLATFORM_BININT 1
#else
#  error Unsupported decimal floating point platform.
BSLMF_ASSERT(false);
#endif
 
// The Decimal Platform macros for endian settings allow for the possibility of
// future implementations which have divergent integer and decimal floating
// point byte orders.
 
#ifdef BSLS_PLATFORM_IS_BIG_ENDIAN
#  define BDLDFP_DECIMALPLATFORM_BIG_ENDIAN    1
#elif defined(BSLS_PLATFORM_IS_LITTLE_ENDIAN)
#  define BDLDFP_DECIMALPLATFORM_LITTLE_ENDIAN 1
#else
#  error "Unsupported endianness"
BSLMF_ASSERT(false);
#endif
 
#define BDLDFP_DECIMALPLATFORM_COMPILER_ERROR BSLMF_ASSERT(false)
 
                        // Validation
 
// The following checks are performed to guarantee the reasonable
// initialization of the compile time features defined in this component.
 
 
// Verify exactly one Implementation class (Hardware or software)
 
#if BDLDFP_DECIMALPLATFORM_HARDWARE                                           \
  + BDLDFP_DECIMALPLATFORM_SOFTWARE != 1
    #error "Exactly one decimal platform implementation class must be set."
    BDLDFP_DECIMALPLATFORM_COMPILER_ERROR;
#endif
 
// Verify exactly one endian selection must be made
 
#if BDLDFP_DECIMALPLATFORM_BIG_ENDIAN                                         \
  + BDLDFP_DECIMALPLATFORM_LITTLE_ENDIAN != 1
    #error "Exactly one decimal platform endian selection must be set."
    BDLDFP_DECIMALPLATFORM_COMPILER_ERROR;
#endif
 
// Verify exactly one format selection must be made
 
#if BDLDFP_DECIMALPLATFORM_DPD                                                \
  + BDLDFP_DECIMALPLATFORM_BININT != 1
    #error "Exactly one decimal platform format selection must be set."
    BDLDFP_DECIMALPLATFORM_COMPILER_ERROR;
#endif
 
// Verify exactly one implementation library must be selected
 
#if BDLDFP_DECIMALPLATFORM_INTELDFP                                           \
  + BDLDFP_DECIMALPLATFORM_C99_TR != 1
    #error "Exactly one decimal implementation library must be selected."
    BDLDFP_DECIMALPLATFORM_COMPILER_ERROR;
#endif
 
// Under Intel implementation, SOFTWARE and BININT must be set
#if defined(BDLDFP_DECIMALPLATFORM_INTELDFP) && \
   !defined(BDLDFP_DECIMALPLATFORM_SOFTWARE) && \
   !defined(BDLDFP_DECIMALPLATFORM_BININT)
    #error "INTELDFP mode requires SOFTWARE and BININT modes to be set."
    BDLDFP_DECIMALPLATFORM_COMPILER_ERROR;
#endif
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2014 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */