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[/] [ao486/] [trunk/] [syn/] [soc/] [firmware/] [exe_bsp/] [HAL/] [src/] [alt_sbrk.c] - Rev 2
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/****************************************************************************** * * * License Agreement * * * * Copyright (c) 2004 Altera Corporation, San Jose, California, USA. * * All rights reserved. * * * * Permission is hereby granted, free of charge, to any person obtaining a * * copy of this software and associated documentation files (the "Software"), * * to deal in the Software without restriction, including without limitation * * the rights to use, copy, modify, merge, publish, distribute, sublicense, * * and/or sell copies of the Software, and to permit persons to whom the * * Software is furnished to do so, subject to the following conditions: * * * * The above copyright notice and this permission notice shall be included in * * all copies or substantial portions of the Software. * * * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * * DEALINGS IN THE SOFTWARE. * * * * This agreement shall be governed in all respects by the laws of the State * * of California and by the laws of the United States of America. * * * * Altera does not recommend, suggest or require that this reference design * * file be used in conjunction or combination with any other product. * ******************************************************************************/ #include <sys/types.h> #include "os/alt_syscall.h" #include "sys/alt_irq.h" #include "sys/alt_stack.h" #include "system.h" /* * sbrk() is called to dynamically extend the data segment for the application. * Thie input argument "incr" is the size of the block to allocate. * * This simple implementation does not perform any bounds checking. Memory will * be allocated, even if the request region colides with the stack or overflows * the available physical memory. * * ALT_SBRK is mapped onto the sbrk() system call in alt_syscall.h * * This function is called by the profiling code to allocate memory so must be * safe if called from an interrupt context. It must also not be instrumented * because that would lead to an infinate loop. */ extern char __alt_heap_start[]; /* set by linker */ extern char __alt_heap_limit[]; /* set by linker */ static char *heap_end = __alt_heap_start; #if defined(ALT_EXCEPTION_STACK) && defined(ALT_STACK_CHECK) char * alt_exception_old_stack_limit = NULL; #endif caddr_t ALT_SBRK (int incr) __attribute__ ((no_instrument_function )); caddr_t ALT_SBRK (int incr) { alt_irq_context context; char *prev_heap_end; context = alt_irq_disable_all(); /* Always return data aligned on a word boundary */ heap_end = (char *)(((unsigned int)heap_end + 3) & ~3); #ifdef ALT_MAX_HEAP_BYTES /* * User specified a maximum heap size. Return -1 if it would * be exceeded by this sbrk call. */ if (((heap_end + incr) - __alt_heap_start) > ALT_MAX_HEAP_BYTES) { alt_irq_enable_all(context); return (caddr_t)-1; } #else if ((heap_end + incr) > __alt_heap_limit) { alt_irq_enable_all(context); return (caddr_t)-1; } #endif prev_heap_end = heap_end; heap_end += incr; #ifdef ALT_STACK_CHECK /* * If the stack and heap are contiguous then extending the heap reduces the * space available for the stack. If we are still using the default stack * then adjust the stack limit to note this, while checking for stack * pointer overflow. * If the stack limit isn't pointing at the top of the heap then the code * is using a different stack so none of this needs to be done. */ if (alt_stack_limit() == prev_heap_end) { if (alt_stack_pointer() <= heap_end) alt_report_stack_overflow(); alt_set_stack_limit(heap_end); } #ifdef ALT_EXCEPTION_STACK /* * If we are executing from the exception stack then compare against the * stack we switched away from as well. The exception stack is a fixed * size so doesn't need to be checked. */ if (alt_exception_old_stack_limit == prev_heap_end) { if (alt_exception_old_stack_limit <= heap_end) alt_report_stack_overflow(); alt_exception_old_stack_limit = heap_end; } #endif #endif alt_irq_enable_all(context); return (caddr_t) prev_heap_end; }