Last change
on this file since 575 was
444,
checked in by satin@…, 7 years ago
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add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc
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File size:
1.2 KB
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Line | |
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1 | #ifdef USING_SIM_SPECS |
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2 | |
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3 | // Gdb simulator requires that sbrk be implemented without a syscall. |
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4 | extern char _end[]; /* _end is set in the linker command file */ |
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5 | char *heap_ptr; |
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6 | |
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7 | /* |
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8 | * sbrk -- changes heap size size. Get nbytes more |
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9 | * RAM. We just increment a pointer in what's |
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10 | * left of memory on the board. |
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11 | */ |
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12 | char * |
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13 | _sbrk (nbytes) |
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14 | int nbytes; |
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15 | { |
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16 | char *base; |
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17 | |
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18 | if (!heap_ptr) |
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19 | heap_ptr = (char *)&_end; |
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20 | base = heap_ptr; |
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21 | heap_ptr += nbytes; |
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22 | |
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23 | return base; |
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24 | } |
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25 | |
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26 | #else |
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27 | |
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28 | // QEMU uses a syscall. |
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29 | #include <machine/syscall.h> |
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30 | #include <sys/types.h> |
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31 | #include "internal_syscall.h" |
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32 | |
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33 | /* Increase program data space. As malloc and related functions depend |
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34 | on this, it is useful to have a working implementation. The following |
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35 | is suggested by the newlib docs and suffices for a standalone |
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36 | system. */ |
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37 | void * |
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38 | _sbrk(ptrdiff_t incr) |
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39 | { |
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40 | static unsigned long heap_end; |
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41 | |
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42 | if (heap_end == 0) |
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43 | { |
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44 | long brk = syscall_errno (SYS_brk, 0, 0, 0, 0, 0, 0); |
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45 | if (brk == -1) |
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46 | return (void *)-1; |
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47 | heap_end = brk; |
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48 | } |
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49 | |
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50 | if (syscall_errno (SYS_brk, heap_end + incr, 0, 0, 0, 0, 0) != heap_end + incr) |
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51 | return (void *)-1; |
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52 | |
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53 | heap_end += incr; |
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54 | return (void *)(heap_end - incr); |
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55 | } |
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56 | #endif |
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