Last change
on this file since 486 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:
1.3 KB
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Rev | Line | |
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[444] | 1 | /* Code to byte-swap static constructor/destructor tables on |
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| 2 | broken a.out little-endian targets. The startup code should call |
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| 3 | __fix_ctors just before calling main. It is safe to use on non-broken |
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| 4 | or big-endian targets. */ |
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| 5 | |
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| 6 | extern long __CTOR_LIST__[]; |
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| 7 | extern long __DTOR_LIST__[]; |
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| 8 | |
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| 9 | static void |
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| 10 | byte_swap (long *entry) |
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| 11 | { |
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| 12 | unsigned char *p = (unsigned char *)entry; |
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| 13 | unsigned char tmp; |
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| 14 | |
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| 15 | tmp = p[0]; |
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| 16 | p[0] = p[3]; |
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| 17 | p[3] = tmp; |
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| 18 | tmp = p[1]; |
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| 19 | p[1] = p[2]; |
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| 20 | p[2] = tmp; |
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| 21 | } |
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| 22 | |
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| 23 | static void |
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| 24 | fix_table (long *table) |
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| 25 | { |
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| 26 | long len = table[0]; |
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| 27 | |
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| 28 | /* The heuristic for deciding if a table is broken is to examine |
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| 29 | the word at the start of the table, which contains the number |
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| 30 | of function pointers immediately following. If the low word |
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| 31 | is zero, and the high word is non-zero, it's very likely that |
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| 32 | it is byte-swapped. This test will fail if the program has |
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| 33 | an exact multiple of 64K static constructors or destructors, a very |
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| 34 | unlikely situation. */ |
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| 35 | if ((len & 0xffff) == 0 && (len & 0xffff0000) != 0) |
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| 36 | { |
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| 37 | |
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| 38 | /* The table looks broken. Byte-swap all the words in the table, up |
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| 39 | to a NULL entry, which marks the end of the table. */ |
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| 40 | do |
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| 41 | { |
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| 42 | byte_swap (table); |
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| 43 | table++; |
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| 44 | } |
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| 45 | while (*table); |
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| 46 | } |
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| 47 | } |
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| 48 | |
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| 49 | void |
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| 50 | __fix_ctors (void) |
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| 51 | { |
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| 52 | fix_table (__CTOR_LIST__); |
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| 53 | fix_table (__DTOR_LIST__); |
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| 54 | } |
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