1@section Implementation details
2
3
4@subsection Internal functions
5
6
7@strong{Description}@*
8These routines are used within BFD.
9They are not intended for export, but are documented here for
10completeness.
11
12@findex bfd_write_bigendian_4byte_int
13@subsubsection @code{bfd_write_bigendian_4byte_int}
14@strong{Synopsis}
15@example
16bfd_boolean bfd_write_bigendian_4byte_int (bfd *, unsigned int);
17@end example
18@strong{Description}@*
19Write a 4 byte integer @var{i} to the output BFD @var{abfd}, in big
20endian order regardless of what else is going on.  This is useful in
21archives.
22
23@findex bfd_put_size
24@subsubsection @code{bfd_put_size}
25@findex bfd_get_size
26@subsubsection @code{bfd_get_size}
27@strong{Description}@*
28These macros as used for reading and writing raw data in
29sections; each access (except for bytes) is vectored through
30the target format of the BFD and mangled accordingly. The
31mangling performs any necessary endian translations and
32removes alignment restrictions.  Note that types accepted and
33returned by these macros are identical so they can be swapped
34around in macros---for example, @file{libaout.h} defines @code{GET_WORD}
35to either @code{bfd_get_32} or @code{bfd_get_64}.
36
37In the put routines, @var{val} must be a @code{bfd_vma}.  If we are on a
38system without prototypes, the caller is responsible for making
39sure that is true, with a cast if necessary.  We don't cast
40them in the macro definitions because that would prevent @code{lint}
41or @code{gcc -Wall} from detecting sins such as passing a pointer.
42To detect calling these with less than a @code{bfd_vma}, use
43@code{gcc -Wconversion} on a host with 64 bit @code{bfd_vma}'s.
44@example
45
46/* Byte swapping macros for user section data.  */
47
48#define bfd_put_8(abfd, val, ptr) \
49  ((void) (*((unsigned char *) (ptr)) = (val) & 0xff))
50#define bfd_put_signed_8 \
51  bfd_put_8
52#define bfd_get_8(abfd, ptr) \
53  (*(unsigned char *) (ptr) & 0xff)
54#define bfd_get_signed_8(abfd, ptr) \
55  (((*(unsigned char *) (ptr) & 0xff) ^ 0x80) - 0x80)
56
57#define bfd_put_16(abfd, val, ptr) \
58  BFD_SEND (abfd, bfd_putx16, ((val),(ptr)))
59#define bfd_put_signed_16 \
60  bfd_put_16
61#define bfd_get_16(abfd, ptr) \
62  BFD_SEND (abfd, bfd_getx16, (ptr))
63#define bfd_get_signed_16(abfd, ptr) \
64  BFD_SEND (abfd, bfd_getx_signed_16, (ptr))
65
66#define bfd_put_32(abfd, val, ptr) \
67  BFD_SEND (abfd, bfd_putx32, ((val),(ptr)))
68#define bfd_put_signed_32 \
69  bfd_put_32
70#define bfd_get_32(abfd, ptr) \
71  BFD_SEND (abfd, bfd_getx32, (ptr))
72#define bfd_get_signed_32(abfd, ptr) \
73  BFD_SEND (abfd, bfd_getx_signed_32, (ptr))
74
75#define bfd_put_64(abfd, val, ptr) \
76  BFD_SEND (abfd, bfd_putx64, ((val), (ptr)))
77#define bfd_put_signed_64 \
78  bfd_put_64
79#define bfd_get_64(abfd, ptr) \
80  BFD_SEND (abfd, bfd_getx64, (ptr))
81#define bfd_get_signed_64(abfd, ptr) \
82  BFD_SEND (abfd, bfd_getx_signed_64, (ptr))
83
84#define bfd_get(bits, abfd, ptr)                       \
85  ((bits) == 8 ? (bfd_vma) bfd_get_8 (abfd, ptr)       \
86   : (bits) == 16 ? bfd_get_16 (abfd, ptr)             \
87   : (bits) == 32 ? bfd_get_32 (abfd, ptr)             \
88   : (bits) == 64 ? bfd_get_64 (abfd, ptr)             \
89   : (abort (), (bfd_vma) - 1))
90
91#define bfd_put(bits, abfd, val, ptr)                  \
92  ((bits) == 8 ? bfd_put_8  (abfd, val, ptr)           \
93   : (bits) == 16 ? bfd_put_16 (abfd, val, ptr)                \
94   : (bits) == 32 ? bfd_put_32 (abfd, val, ptr)                \
95   : (bits) == 64 ? bfd_put_64 (abfd, val, ptr)                \
96   : (abort (), (void) 0))
97
98@end example
99
100@findex bfd_h_put_size
101@subsubsection @code{bfd_h_put_size}
102@strong{Description}@*
103These macros have the same function as their @code{bfd_get_x}
104brethren, except that they are used for removing information
105for the header records of object files. Believe it or not,
106some object files keep their header records in big endian
107order and their data in little endian order.
108@example
109
110/* Byte swapping macros for file header data.  */
111
112#define bfd_h_put_8(abfd, val, ptr) \
113  bfd_put_8 (abfd, val, ptr)
114#define bfd_h_put_signed_8(abfd, val, ptr) \
115  bfd_put_8 (abfd, val, ptr)
116#define bfd_h_get_8(abfd, ptr) \
117  bfd_get_8 (abfd, ptr)
118#define bfd_h_get_signed_8(abfd, ptr) \
119  bfd_get_signed_8 (abfd, ptr)
120
121#define bfd_h_put_16(abfd, val, ptr) \
122  BFD_SEND (abfd, bfd_h_putx16, (val, ptr))
123#define bfd_h_put_signed_16 \
124  bfd_h_put_16
125#define bfd_h_get_16(abfd, ptr) \
126  BFD_SEND (abfd, bfd_h_getx16, (ptr))
127#define bfd_h_get_signed_16(abfd, ptr) \
128  BFD_SEND (abfd, bfd_h_getx_signed_16, (ptr))
129
130#define bfd_h_put_32(abfd, val, ptr) \
131  BFD_SEND (abfd, bfd_h_putx32, (val, ptr))
132#define bfd_h_put_signed_32 \
133  bfd_h_put_32
134#define bfd_h_get_32(abfd, ptr) \
135  BFD_SEND (abfd, bfd_h_getx32, (ptr))
136#define bfd_h_get_signed_32(abfd, ptr) \
137  BFD_SEND (abfd, bfd_h_getx_signed_32, (ptr))
138
139#define bfd_h_put_64(abfd, val, ptr) \
140  BFD_SEND (abfd, bfd_h_putx64, (val, ptr))
141#define bfd_h_put_signed_64 \
142  bfd_h_put_64
143#define bfd_h_get_64(abfd, ptr) \
144  BFD_SEND (abfd, bfd_h_getx64, (ptr))
145#define bfd_h_get_signed_64(abfd, ptr) \
146  BFD_SEND (abfd, bfd_h_getx_signed_64, (ptr))
147
148/* Aliases for the above, which should eventually go away.  */
149
150#define H_PUT_64  bfd_h_put_64
151#define H_PUT_32  bfd_h_put_32
152#define H_PUT_16  bfd_h_put_16
153#define H_PUT_8   bfd_h_put_8
154#define H_PUT_S64 bfd_h_put_signed_64
155#define H_PUT_S32 bfd_h_put_signed_32
156#define H_PUT_S16 bfd_h_put_signed_16
157#define H_PUT_S8  bfd_h_put_signed_8
158#define H_GET_64  bfd_h_get_64
159#define H_GET_32  bfd_h_get_32
160#define H_GET_16  bfd_h_get_16
161#define H_GET_8   bfd_h_get_8
162#define H_GET_S64 bfd_h_get_signed_64
163#define H_GET_S32 bfd_h_get_signed_32
164#define H_GET_S16 bfd_h_get_signed_16
165#define H_GET_S8  bfd_h_get_signed_8
166
167
168@end example
169
170@findex bfd_log2
171@subsubsection @code{bfd_log2}
172@strong{Synopsis}
173@example
174unsigned int bfd_log2 (bfd_vma x);
175@end example
176@strong{Description}@*
177Return the log base 2 of the value supplied, rounded up.  E.g., an
178@var{x} of 1025 returns 11.  A @var{x} of 0 returns 0.
179
180