HP-UX Reference (11i v2 03/08) - 4 File Formats (vol 8)

a.out(4) a.out(4)

R_LTP_OVERRIDE

220 1 none

R_COMMENT 221 6 OP=B1;V=B2toB6

R_TP_OVERRIDE 222 1 none

R_RESERVED 224-255 reserved

Parameter relocation bits are encoded in the ﬁxup requests in two ways, noted as rbits1 and rbits2 in the

above table.

The ﬁrst encoding recognizes that the most common procedure calls have only general register arguments

with no holes in the parameter list. The encoding for such calls is simply the number of parameters in

general registers (0 to 4), plus 5 if there is a return value in a general register.

The second encoding is more complex. The 10 argument relocation bits are compressed into 9 bits by

eliminating some impossible combinations. The encoding is the combination of three contributions. The

ﬁrst contribution is the pair of bits for the return value, which are not modiﬁed. The second contribution

is 9 if the ﬁrst two parameter words together form a double-precision parameter; otherwise, it is 3 times

the pair of bits for the ﬁrst word plus the pair of bits for the second word. Similarly, the third contribu-

tion is formed based on the third and fourth parameter words. The second contribution is multiplied by

40, the third is multiplied by 4, then the three are added together.

Compiler Records

Compiler records are placed in relocatable ﬁles by each compiler or assembler to identify the version of

the compiler that was used to produce the ﬁle. These records are copied into the executable ﬁle by the

linker, but are strippable. The structure of a compiler record is shown below. All strings are contained

in the symbol string table.

The format of the compilation record is described by the following structure declaration from

<compunit.h>.

struct compilation_unit {

union name_pt name; /* entry name */

union name_pt language_name; /* language used */

union name_pt product_id; /* compiler ID */

union name_pt version_id; /* compiler version */

unsigned int reserved: 31; /* reserved */

unsigned int chunk_flag: 1; /* MPE-only */

struct sys_clock compile_time; /* time file was compiled */

struct sys_clock source_time; /* time file was last modified */

};

FILES

<a.out.h>

<aouthdr.h>

<compunit.h>

<elf.h>

<filehdr.h>

<reloc.h>

<scnhdr.h>

<spacehdr.h>

<syms.h>