2012-02-21 Jeremy Bennett <jeremy.bennett@embecosm.com>
Alan Lehotsky <apl@alum.mit.edu> Joern Rennecke <joern.rennecke@embecosm.com> * configure.in: Add Epiphany support. * configure: Regenerate. * epiphany: New directory. * libgloss/README: Add Epiphany entry.
This commit is contained in:
Jeff Johnston
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libgloss/epiphany/sbrk.c
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libgloss/epiphany/sbrk.c
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/* EPIPHANY implementation of _sbrk ()
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Copyright (c) 2011, Adapteva, Inc.
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All rights reserved.
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Contributor Jeremy Bennett <jeremy.bennett@embecosm.com> for Adapteva Inc
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of Adapteva nor the names of its contributors may be
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used to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE. */
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/* ------------------------------------------------------------------------- */
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/* This implementation is suitable for use with the Verilator simulation of
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the EPIPHANY.
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Commenting suitable for processing by Doxygen is provided throughout. */
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/* ------------------------------------------------------------------------- */
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#include <sys/types.h>
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#include <errno.h>
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#include <stddef.h>
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/* ------------------------------------------------------------------------- */
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/*!Increase program data space
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This is a minimal implementation. Assuming the heap is growing upwards
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from __heap_start towards __heap_end.
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See linker file for definition.
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@param[in] incr The number of bytes to increment the stack by.
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@return A pointer to the start of the new block of memory */
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/* ------------------------------------------------------------------------- */
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void *
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_sbrk (int incr)
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{
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extern char __heap_start;//set by linker
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extern char __heap_end;//set by linker
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static char *heap_end; /* Previous end of heap or 0 if none */
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char *prev_heap_end;
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if (0 == heap_end) {
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heap_end = &__heap_start; /* Initialize first time round */
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}
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prev_heap_end = heap_end;
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heap_end += incr;
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//check
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if( heap_end < (&__heap_end)) {
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} else {
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errno = ENOMEM;
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return (char*)-1;
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}
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return (void *) prev_heap_end;
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} /* _sbrk () */
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///* sbrk support */
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//
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///* The current plan is to have one sbrk handler for all cpus.
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// Hence use `asm' for each global variable here to avoid the cpu prefix.
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// We can't intrude on the user's namespace (another reason to use asm). */
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//
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//#include <sys/types.h>
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///*#include <sys/syscall.h>*/
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//#include <errno.h>
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//#include <stddef.h>
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//
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///* These variables are publicly accessible for debugging purposes.
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// The user is also free to set sbrk_size to something different.
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// See mem-layout.c. */
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//
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//extern int sbrk_size asm ("sbrk_size");
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//
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//caddr_t sbrk_start asm ("sbrk_start");
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//caddr_t sbrk_loc asm ("sbrk_loc");
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//extern char end; /* Defined by linker. */
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//
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///*caddr_t _sbrk_r (struct _reent *, size_t) asm ("__sbrk_r");*/
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//
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//
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///* This symbol can be defined with the --defsym linker option. */
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//extern char __heap_end __attribute__((weak));
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//
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//
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///* FIXME: We need a semaphore here. */
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//
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//caddr_t
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//_sbrk_r (struct _reent *r, size_t nbytes)
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//{
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// extern char end; /* Defined by linker. */
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// static char *heap_end; /* Previous end of heap or 0 if none */
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// char *prev_heap_end;
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// register char* stack asm("sp");
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//
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// if (0 == heap_end)
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// {
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// heap_end = &end; /* Initialize first time round */
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// }
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//
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// prev_heap_end = heap_end;
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//
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// if (stack < (prev_heap_end+nbytes)) {
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// /* heap would overlap the current stack depth.
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// * Future: use sbrk() system call to make simulator grow memory beyond
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// * the stack and allocate that
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// */
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// errno = ENOMEM;
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// return (char*)-1;
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// }
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//
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// heap_end += nbytes;
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//
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// return (caddr_t) prev_heap_end;
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//
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//} /* _sbrk () */
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//caddr_t
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//_sbrk_r (struct _reent *r, size_t nbytes)
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//{
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// caddr_t result;
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//
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// void *heap_end;
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//
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// heap_end = &__heap_end;
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// if (!heap_end)
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// heap_end = sbrk_start + sbrk_size;
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// if (
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// /* Ensure we don't underflow. */
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// sbrk_loc + nbytes < sbrk_start
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// /* Ensure we don't overflow. */
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// || sbrk_loc + nbytes > (caddr_t)heap_end)
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// {
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// errno = ENOMEM;
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// return ((caddr_t) -1);
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// }
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//
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// if (0 == sbrk_loc)
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// sbrk_loc = &end; /* Initialize first time round */
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// result = sbrk_loc;
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// sbrk_loc += nbytes;
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// return result;
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//}
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