Last change
on this file since 548 was
444,
checked in by satin@…, 6 years ago
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add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc
|
File size:
1.1 KB
|
Rev | Line | |
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[444] | 1 | #include <_ansi.h> |
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| 2 | #include <sys/types.h> |
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| 3 | #include <sys/stat.h> |
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| 4 | |
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| 5 | #include "regs.S" |
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| 6 | |
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| 7 | extern char _end[]; |
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| 8 | |
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| 9 | /* FIXME: This is not ideal, since we do a get_mem_info() call for |
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| 10 | every sbrk() call. */ |
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| 11 | char * |
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| 12 | sbrk (nbytes) |
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| 13 | int nbytes; |
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| 14 | { |
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| 15 | static char *heap_ptr = _end; |
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| 16 | static char *heap_start = _end; |
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| 17 | char *base; |
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| 18 | struct s_mem { |
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| 19 | unsigned int size; |
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| 20 | unsigned int icsize; |
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| 21 | unsigned int dcsize; |
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| 22 | } mem; |
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| 23 | unsigned int avail = 0; |
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| 24 | |
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| 25 | /* The sizeof (s_mem.size) must be 4 bytes. The compiler should be |
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| 26 | able to eliminate this check */ |
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| 27 | if (sizeof (unsigned int) != 4) |
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| 28 | return (char *)-1; |
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| 29 | |
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| 30 | get_mem_info(&mem); |
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| 31 | /* NOTE: The value returned from the get_mem_info call is the amount |
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| 32 | of memory, and not the address of the (last byte + 1) */ |
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| 33 | |
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| 34 | if (((size_t)heap_ptr >= heap_start) && ((size_t)heap_ptr < (heap_start + mem.size))) { |
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| 35 | avail = (heap_start + mem.size) - (size_t)heap_ptr; |
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| 36 | base = heap_ptr; |
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| 37 | } /* else will fail since "nbytes" will be greater than zeroed "avail" value */ |
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| 38 | |
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| 39 | if ((nbytes > avail) || (heap_ptr + nbytes < _end)) |
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| 40 | base = (char *)-1; |
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| 41 | else |
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| 42 | heap_ptr += nbytes; |
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| 43 | |
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| 44 | return base; |
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| 45 | } |
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