36ab90385f
rather than the Linux way; various non-C bits of the ACK assume it takes an int, so it's cleaner).
43 lines
753 B
C
43 lines
753 B
C
/* $Source$
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* $State$
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* $Revision$
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*/
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#include <stdlib.h>
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#include <errno.h>
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#include <unistd.h>
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#define OUT_OF_MEMORY (void*)(-1) /* sbrk returns this on failure */
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#define STACK_BUFFER 128 /* number of bytes to leave for stack */
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extern char _end[1];
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static char* current = _end;
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int brk(void* newend)
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{
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/* We determine the amount of free memory by looking at the address of the
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* BDOS vector at 0x0006. */
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char* memtop = (char*) ((*(unsigned char*)0x0007)<<8);
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char* p = newend;
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if ((p >= memtop) ||
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(p < _end))
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return -1;
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current = p;
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return 0;
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}
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void* sbrk(int increment)
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{
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char* old;
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if (increment == 0)
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return current;
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old = current;
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if (brk(old + increment) < 0)
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return OUT_OF_MEMORY;
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return old;
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}
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