Last change
on this file since 617 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:
1.2 KB
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Rev | Line | |
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[444] | 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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