/* $Source$ * $State$ * $Revision$ */ #include #include #include #define OUT_OF_MEMORY (void*)(-1) /* sbrk returns this on failure */ #define STACK_BUFFER 128 /* number of bytes to leave for stack */ extern char _end[1]; static char* current = _end; int brk(void* newend) { /* We determine the amount of free memory by looking at the address of the * BDOS vector at 0x0006. */ char* memtop = (char*) ((*(unsigned char*)0x0007)<<8); char* p = newend; if ((p >= memtop) || (p < _end)) return -1; current = p; return 0; } void* sbrk(intptr_t increment) { char* old; if (increment == 0) return current; old = current; if (brk(old + increment) < 0) return OUT_OF_MEMORY; return old; }