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Libraries and Floating Point Support Guide

Conventions and feedback The ARM C and C++ libraries Mandatory linkage with the C library C and C++ runtime libraries C and C++ library features Library heap usage requirements of the ARM C and C Compliance with the Application Binary Interface ( Increasing portability of object files to other CL ARM C and C++ library directory structure Selection of ARM C and C++ library variants based Thumb C libraries C++ and C libraries and the std namespace ARM C libraries and multithreading ARM C libraries and reentrant functions ARM C libraries and thread-safe functions Use of static data in the C libraries Use of the __user_libspace static data area by the C library functions to access subsections of the _ Re-implementation of legacy function __user_libspa Management of locks in multithreaded applications How to ensure re-implemented mutex functions are c Using the ARM C library in a multithreaded environ Thread safety in the ARM C library Thread safety in the ARM C++ library The floating-point status word in a multithreaded Using the C library with an application Using the C and C++ libraries with an application Using $Sub$$ to mix semihosted and nonsemihosted I Using the libraries in a nonsemihosting environmen C++ exceptions in a non-semihosting environment Direct semihosting C library function dependencies Indirect semihosting C library function dependenci C library API definitions for targeting a differen Building an application without the C library Creating an application as bare machine C without Integer and floating-point compiler functions and Bare machine integer C Bare machine C with floating-point processing Customized C library startup code and access to C Program design when exploiting the C library Using low-level functions when exploiting the C li Using high-level functions when exploiting the C l Using malloc() when exploiting the C library Tailoring the C library to a new execution environ How C and C++ programs use the library functions Initialization of the execution environment and ex C++ initialization, construction and destruction Legacy support for C$$pi_ctorvec instead of .init_ Exceptions system initialization Emergency buffer memory for exceptions Library functions called from main() Program exit and the assert macro Assembler macros that tailor locale functions in t Link time selection of the locale subsystem in the ISO8859-1 implementation Shift-JIS and UTF-8 implementation Runtime selection of the locale subsystem in the C Definition of locale data blocks in the C library LC_CTYPE data block LC_COLLATE data block LC_MONETARY data block LC_NUMERIC data block LC_TIME data block Modification of C library functions for error sign Modification of memory management functions in the Avoiding the heap and heap-using library functions C library support for memory allocation functions Heap1, standard heap implementation Heap2, alternative heap implementation Using a heap implementation from bare machine C Stack pointer initialization and heap bounds Defining __initial_sp, __heap_base and __heap_limi Extending heap size at runtime Legacy support for __user_initial_stackheap() Tailoring input/output functions in the C and C++ Target dependencies on low-level functions in the The C library printf family of functions The C library scanf family of functions Redefining low-level library functions to enable d The C library functions fread(), fgets() and gets( Re-implementing __backspace() in the C library Re-implementing __backspacewc() in the C library Redefining target-dependent system I/O functions i Tailoring non-input/output C library functions Real-time integer division in the ARM libraries Selecting real-time division in the ARM libraries How the ARM C library fulfills ISO C specification mathlib error handling ISO-compliant implementation of signals supported ISO-compliant C library input/output characteristi Standard C++ library implementation definition C library functions and extensions Persistence of C and C++ library names across rele Link time selection of C and C++ libraries Managing projects that have explicit C or C++ libr Compiler generated and library-resident helper fun C and C++ library naming conventions Using macro__ARM_WCHAR_NO_IO to disable FILE decla The ARM C micro-library Floating-point support

Libraries and Floating Point Support Guide

C and C++ library naming conventions

C and C++ library naming conventions

The library filename identifies how the variant was built. The values for the fields of the filename, and the relevant build options are:

*root/prefix_arch[fpu][entrant][enum][wchar].endian

root
armlib

An ARM C library.

cpplib

An ARM C++ library.

prefix
c

ISO C and C++ basic runtime support.

cpp

Rogue Wave C++ library.

cpprt

The ARM C++ runtime libraries.

f

--fpmode=ieee_fixed.

IEEE-compliant library with a fixed rounding mode (round to nearest) and no inexact exceptions.

fj

--fpmode=ieee_no_fenv.

IEEE-compliant library with a fixed rounding mode (round to nearest) and no exceptions.

fz

--fpmode=fast or --fpmode=std.

Behaves like the fj library, but additionally flushes denormals and infinities to zero.

This library behaves like the ARM VFP in Fast mode. This is the default.

g

--fpmode=ieee_full.

IEEE-compliant library with configurable rounding mode and all IEEE exceptions.

h

Compiler support (helper) library.

m

Transcendental math functions.

mc

Non ISO C-compliant ISO C micro-library basic runtime support.

mf

Non IEEE 754 floating-point compliant micro-library support.

arch
4

An ARM only library for use with ARMv4.

t

An ARM/Thumb interworking library for use with ARMv4T.

5

An ARM/Thumb interworking library for use with ARMv5T and later.

w

A Thumb only library for use with Cortex-M3.

p

A Thumb only library for use with Cortex-M1 and Cortex-M0.

2

A combined ARM and Thumb library for use with Cortex-R series processor cores. You can prevent this library being selected using the linker option --no_thumb2_library.

fpu
m

A variant of the library for processors that have single-precision hardware floating-point only, such as Cortex-M4.

v

Uses VFP instruction set.

s

Soft VFP.

Note

If neither v nor s is present in a library name, the library provides no floating-point support.

entrant
e

Position-independent access to static data.

f

FPIC addressing is enabled.

Note

If neither e nor f is present in a library name, the library uses position-dependent access to static data.

enum
n

Compatible with the compiler option, --enum_is_int.

wchar
u

Indicates the size of wchar_t.When present, the library is compatible with the compiler option, --wchar32. Otherwise, it is compatible with --wchar16

endian
l

Little-endian.

b

Big-endian.

For example:

*armlib/c_4.b
*cpplib/cpprt_5f.l

Note

Not all variant/name combinations are valid. See the armlib and cpplib directories for the libraries that are supplied with the ARM compilation tools.

The linker command-line option --info libraries provides information on every library that is automatically selected for the link stage.

Copyright © 2007-2008, 2011-2012 ARM. All rights reserved.ARM DUI 0378D
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