iPXE
compiler.h
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1 #ifndef _BITS_COMPILER_H
2 #define _BITS_COMPILER_H
3 
4 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
5 
6 /** Dummy relocation type */
7 #define RELOC_TYPE_NONE R_386_NONE
8 
9 #ifndef ASSEMBLY
10 
11 /** Unprefixed constant operand modifier */
12 #define ASM_NO_PREFIX "c"
13 
14 /** Declare a function with standard calling conventions */
15 #define __asmcall __attribute__ (( cdecl, regparm(0) ))
16 
17 /**
18  * Declare a function with libgcc implicit linkage
19  *
20  * It seems as though gcc expects its implicit arithmetic functions to
21  * be cdecl, even if -mrtd is specified. This is somewhat
22  * inconsistent; for example, if -mregparm=3 is used then the implicit
23  * functions do become regparm(3).
24  *
25  * The implicit calls to memcpy() and memset() which gcc can generate
26  * do not seem to have this inconsistency; -mregparm and -mrtd affect
27  * them in the same way as any other function.
28  *
29  * Update (25/4/14): it appears that more recent gcc versions do allow
30  * -mrtd to affect calls to the implicit arithmetic functions. There
31  * is nothing obvious in the gcc changelogs to indicate precisely when
32  * this happened. From experimentation with available gcc versions,
33  * the change occurred sometime between v4.6.3 and v4.7.2. We assume
34  * that only versions up to v4.6.x require the special treatment.
35  */
36 #if ( __GNUC__ < 4 ) || ( ( __GNUC__ == 4 ) && ( __GNUC_MINOR__ <= 6 ) )
37 #define __libgcc __attribute__ (( cdecl ))
38 #else
39 #define __libgcc
40 #endif
41 
42 #endif /* ASSEMBLY */
43 
44 #endif /* _BITS_COMPILER_H */
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)