stdlib.cdl

eCos1.31版

# ====================================================================
#
#      stdlib.cdl
#
#      C library stdlib related configuration data
#
# ====================================================================
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# The contents of this file are subject to the Red Hat eCos Public License 
# Version 1.1 (the "License"); you may not use this file except in         
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#                                                                          
# The Original Code is eCos - Embedded Configurable Operating System,      
# released September 30, 1998.                                             
#                                                                          
# The Initial Developer of the Original Code is Red Hat.                   
# Portions created by Red Hat are                                          
# Copyright (C) 1998, 1999, 2000 Red Hat, Inc.                             
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# ====================================================================
######DESCRIPTIONBEGIN####
#
# Author(s):      jskov
# Original data:  jlarmour
# Contributors:
# Date:           1999-07-06
#
#####DESCRIPTIONEND####
#
# ====================================================================

cdl_option CYGIMP_LIBC_STDLIB_INLINES {
    display       "Inline versions of <stdlib.h> functions"
    default_value 1
    description   "
        This option chooses whether some of the
        particularly simple standard utility functions
        from <stdlib.h> are available as inline
        functions. This may improve performance, and as
        the functions are small, may even improve code
        size."
}

cdl_component CYGPKG_LIBC_RAND {
    display       "Random number generation"
    flavor        none
    description   "
        These options control the behaviour of the
        functions rand(), srand() and rand_r()"

    cdl_option CYGSEM_LIBC_PER_THREAD_RAND {
        display       "Per-thread random seed"
        requires      CYGVAR_KERNEL_THREADS_DATA
        default_value 0
        description   "
            This option controls whether the pseudo-random
            number generation functions rand() and srand()
            have their state recorded on a per-thread
            basis rather than global. If this option is
            disabled, some per-thread space can be saved.
            Note there is also a POSIX-standard rand_r()
            function to achieve a similar effect with user
            support. Enabling this option will use one slot
            of kernel per-thread data. You should ensure you
            have enough slots configured for all your
            per-thread data."
    }

    cdl_option CYGNUM_LIBC_RAND_SEED {
        display       "Random number seed"
        flavor        data
        legal_values  0 to 0x7fffffff
        default_value 1
        description   "
            This selects the initial random number seed for
            rand()'s pseudo-random number generator. For
            strict ISO standard compliance, this should be 1,
            as per section 7.10.2.2 of the standard."
    }

    cdl_option CYGNUM_LIBC_RAND_TRACE_LEVEL {
        display       "Tracing level"
        flavor        data
        legal_values  0 to 1
        default_value 0
        description   "
            Trace verbosity level for debugging the rand(),
            srand() and rand_r() functions. Increase this
            value to get additional trace output."
    }

    cdl_interface CYGINT_LIBC_RAND {
        requires 1 == CYGINT_LIBC_RAND
    }

    cdl_option CYGIMP_LIBC_RAND_SIMPLEST {
        display "Simplest implementation"
        flavor bool
        default_value 0
		implements CYGINT_LIBC_RAND
        description "
            This provides a very simple implementation of rand()
                          that does not perform well with randomness in the
                          lower significant bits. However it is exceptionally
                          fast. It uses the sample algorithm from the ISO C
                          standard itself."
    }

    cdl_option CYGIMP_LIBC_RAND_SIMPLE1 {
        display "Simple implementation #1"
        flavor bool
        default_value 1
		implements CYGINT_LIBC_RAND
        description "
            This provides a very simple implementation of rand()
                          based on the simplest implementation above. However
                          it does try to work around the lack of randomness
                          in the lower significant bits, at the expense of a
                          little speed."
    }

    cdl_option CYGIMP_LIBC_RAND_KNUTH1 {
        display "Knuth implementation #1"
        flavor bool
        default_value 0
		implements CYGINT_LIBC_RAND
        description "
            This implements a slightly more complex algorithm
                          published in Donald E. Knuth's Art of Computer
                          Programming Vol.2 section 3.6 (p.185 in the 3rd ed.).
                          This produces better random numbers than the
                          simplest approach but is slower."
    }
}

cdl_component CYGPKG_LIBC_MALLOC {
    display      "Support for dynamic memory allocation"
    flavor        bool
    requires      CYGPKG_KERNEL
    default_value 1
    description   "
        This enables support for dynamic memory
        allocation as supplied by the functions malloc(),
        free(), calloc() and realloc(). As these
        functions are often used, but can have quite an
        overhead, disabling them here can ensure they
        cannot even be used accidentally when static
        allocation is preferred."
    

    cdl_option CYGNUM_LIBC_MALLOC_MEMPOOL_SIZE {
        display       "Size of the dynamic memory pool in bytes"
        flavor        data
        legal_values  32 to 0x7fffffff
        default_value 16384
        description   "
            At this stage, dynamic memory allocation by
            malloc() and calloc() must be from a fixed-size,
            contiguous memory pool (note here that it is the
            pool that is of a fixed size, but malloc() is still
            able to allocate variable sized chunks of memory
            from it). This option is the size
            of that pool, in bytes. Note that not all of
            this is available for programs to
            use - some is needed for internal information
            about memory regions, and some may be lost to
            ensure that memory allocation only returns
            memory aligned on word (or double word)
            boundaries - a very common architecture
            constraint."
    }

    cdl_option CYGIMP_LIBC_MALLOC_CXX_DELETE_CALLS_FREE {
        display       "Support for C++ delete operator"
        default_value 0
        description   "
            C++ new and delete operators can call
            the C library's malloc() and free() implicitly.
            If this is what is required, enable this option.
            However, if enabled, the dynamic memory allocation 
            code is always linked in to the application,
            even if it is not explicitly called and new/delete
            are not used.
            This increases code and data size needlessly."
    }
}
cdl_option CYGFUN_LIBC_strtod {
    display       "Provides strtod() and atof()"
    requires      CYGPKG_LIBM
    default_value 1
    description   "
        This option allows use of the utility function
        strtod() (and consequently atof()) to convert
        from string to double precision floating point
        numbers. Disabling this option removes the
        dependency on the math library package."
}

cdl_option CYGNUM_LIBC_BSEARCH_TRACE_LEVEL {
    display       "bsearch() tracing level"
    flavor        data
    legal_values  0 to 1
    default_value 0
    description   "
        Trace verbosity level for debugging the <stdlib.h>
        binary search function bsearch(). Increase this
        value to get additional trace output."
}

cdl_option CYGNUM_LIBC_QSORT_TRACE_LEVEL {
    display       "qsort() tracing level"
    flavor        data
    legal_values  0 to 1
    default_value 0
    description   "
        Trace verbosity level for debugging the <stdlib.h>
        quicksort function qsort(). Increase this value
        to get additional trace output."
}