Last change
on this file since 656 was
444,
checked in by satin@…, 6 years ago
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add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc
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File size:
1.1 KB
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Line | |
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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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