Component bdldfp_decimalplatform [Package bdldfp]

Provide decimal floating-point platform information macros. More...

Outline

• Purpose
• Macros
• Description
  • Macros Defining the Underlying Implementation
  • Macros Defining Hardware Support vs. Software Emulation
  • Endianness
  • Encoding
  • Implementation Detail Macros
  • Usage

Purpose:

Provide decimal floating-point platform information macros.

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 also:

Component bdldfp_decimal, Component bdldfp_decimalutil, Component bdldfp_decimalconvertutil

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:

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:

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:

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:

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:

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:

In this section, we show the intended usage of this component.