107 lines
3.6 KiB
C
107 lines
3.6 KiB
C
/*
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FUNCTION
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<<vec_malloc>>, <<vec_realloc>>, <<vec_free>>---manage vector memory
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INDEX
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vec_malloc
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INDEX
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vec_realloc
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INDEX
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vec_free
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INDEX
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_vec_malloc_r
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INDEX
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_vec_realloc_r
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INDEX
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_vec_free_r
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SYNOPSIS
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#include <stdlib.h>
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void *vec_malloc(size_t <[nbytes]>);
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void *vec_realloc(void *<[aptr]>, size_t <[nbytes]>);
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void vec_free(void *<[aptr]>);
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void *_vec_malloc_r(void *<[reent]>, size_t <[nbytes]>);
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void *_vec_realloc_r(void *<[reent]>,
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void *<[aptr]>, size_t <[nbytes]>);
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void _vec_free_r(void *<[reent]>, void *<[aptr]>);
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DESCRIPTION
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These functions manage a pool of system memory that is 16-byte aligned..
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Use <<vec_malloc>> to request allocation of an object with at least
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<[nbytes]> bytes of storage available and is 16-byte aligned. If the space is
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available, <<vec_malloc>> returns a pointer to a newly allocated block as its result.
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If you already have a block of storage allocated by <<vec_malloc>>, but
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you no longer need all the space allocated to it, you can make it
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smaller by calling <<vec_realloc>> with both the object pointer and the
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new desired size as arguments. <<vec_realloc>> guarantees that the
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contents of the smaller object match the beginning of the original object.
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Similarly, if you need more space for an object, use <<vec_realloc>> to
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request the larger size; again, <<vec_realloc>> guarantees that the
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beginning of the new, larger object matches the contents of the
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original object.
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When you no longer need an object originally allocated by <<vec_malloc>>
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or <<vec_realloc>> (or the related function <<vec_calloc>>), return it to the
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memory storage pool by calling <<vec_free>> with the address of the object
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as the argument. You can also use <<vec_realloc>> for this purpose by
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calling it with <<0>> as the <[nbytes]> argument.
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The alternate functions <<_vec_malloc_r>>, <<_vec_realloc_r>>, <<_vec_free_r>>,
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are reentrant versions. The extra argument <[reent]> is a pointer to a reentrancy
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structure.
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If you have multiple threads of execution which may call any of these
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routines, or if any of these routines may be called reentrantly, then
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you must provide implementations of the <<__vec_malloc_lock>> and
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<<__vec_malloc_unlock>> functions for your system. See the documentation
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for those functions.
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These functions operate by calling the function <<_sbrk_r>> or
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<<sbrk>>, which allocates space. You may need to provide one of these
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functions for your system. <<_sbrk_r>> is called with a positive
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value to allocate more space, and with a negative value to release
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previously allocated space if it is no longer required.
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@xref{Stubs}.
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RETURNS
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<<vec_malloc>> returns a pointer to the newly allocated space, if
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successful; otherwise it returns <<NULL>>. If your application needs
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to generate empty objects, you may use <<vec_malloc(0)>> for this purpose.
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<<vec_realloc>> returns a pointer to the new block of memory, or <<NULL>>
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if a new block could not be allocated. <<NULL>> is also the result
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when you use `<<vec_realloc(<[aptr]>,0)>>' (which has the same effect as
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`<<vec_free(<[aptr]>)>>'). You should always check the result of
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<<vec_realloc>>; successful vec_reallocation is not guaranteed even when
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you request a smaller object.
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<<vec_free>> does not return a result.
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PORTABILITY
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<<vec_malloc>>, <<vec_realloc>>, and <<vec_free>> are all extensions
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specified in the AltiVec Programming Interface Manual.
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Supporting OS subroutines required: <<sbrk>>. */
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#include <_ansi.h>
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#include <reent.h>
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#include <stdlib.h>
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#include <malloc.h>
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#ifndef _REENT_ONLY
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void *
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_DEFUN (vec_malloc, (nbytes),
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size_t nbytes) /* get a block */
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{
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return _memalign_r (_REENT, 16, nbytes);
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}
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#endif
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