| #include <_ansi.h> |
| #include <sys/types.h> |
| #include <sys/stat.h> |
| |
| #include "regs.S" |
| |
| extern char _end[]; |
| |
| /* FIXME: This is not ideal, since we do a get_mem_info() call for |
| every sbrk() call. */ |
| char * |
| sbrk (nbytes) |
| int nbytes; |
| { |
| static char *heap_ptr = _end; |
| static char *heap_start = _end; |
| char *base; |
| struct s_mem { |
| unsigned int size; |
| unsigned int icsize; |
| unsigned int dcsize; |
| } mem; |
| unsigned int avail = 0; |
| |
| /* The sizeof (s_mem.size) must be 4 bytes. The compiler should be |
| able to eliminate this check */ |
| if (sizeof (unsigned int) != 4) |
| return (char *)-1; |
| |
| get_mem_info(&mem); |
| /* NOTE: The value returned from the get_mem_info call is the amount |
| of memory, and not the address of the (last byte + 1) */ |
| |
| if (((size_t)heap_ptr >= heap_start) && ((size_t)heap_ptr < (heap_start + mem.size))) { |
| avail = (heap_start + mem.size) - (size_t)heap_ptr; |
| base = heap_ptr; |
| } /* else will fail since "nbytes" will be greater than zeroed "avail" value */ |
| |
| if ((nbytes > avail) || (heap_ptr + nbytes < _end)) |
| base = (char *)-1; |
| else |
| heap_ptr += nbytes; |
| |
| return base; |
| } |