@section a.out backends
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@section a.out backends
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@strong{Description}@*
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@strong{Description}@*
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BFD supports a number of different flavours of a.out format,
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BFD supports a number of different flavours of a.out format,
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though the major differences are only the sizes of the
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though the major differences are only the sizes of the
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structures on disk, and the shape of the relocation
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structures on disk, and the shape of the relocation
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information.
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information.
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The support is split into a basic support file @file{aoutx.h}
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The support is split into a basic support file @file{aoutx.h}
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and other files which derive functions from the base. One
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and other files which derive functions from the base. One
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derivation file is @file{aoutf1.h} (for a.out flavour 1), and
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derivation file is @file{aoutf1.h} (for a.out flavour 1), and
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adds to the basic a.out functions support for sun3, sun4, 386
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adds to the basic a.out functions support for sun3, sun4, 386
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and 29k a.out files, to create a target jump vector for a
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and 29k a.out files, to create a target jump vector for a
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specific target.
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specific target.
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This information is further split out into more specific files
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This information is further split out into more specific files
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for each machine, including @file{sunos.c} for sun3 and sun4,
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for each machine, including @file{sunos.c} for sun3 and sun4,
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@file{newsos3.c} for the Sony NEWS, and @file{demo64.c} for a
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@file{newsos3.c} for the Sony NEWS, and @file{demo64.c} for a
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demonstration of a 64 bit a.out format.
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demonstration of a 64 bit a.out format.
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The base file @file{aoutx.h} defines general mechanisms for
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The base file @file{aoutx.h} defines general mechanisms for
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reading and writing records to and from disk and various
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reading and writing records to and from disk and various
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other methods which BFD requires. It is included by
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other methods which BFD requires. It is included by
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@file{aout32.c} and @file{aout64.c} to form the names
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@file{aout32.c} and @file{aout64.c} to form the names
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@code{aout_32_swap_exec_header_in}, @code{aout_64_swap_exec_header_in}, etc.
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@code{aout_32_swap_exec_header_in}, @code{aout_64_swap_exec_header_in}, etc.
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As an example, this is what goes on to make the back end for a
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As an example, this is what goes on to make the back end for a
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sun4, from @file{aout32.c}:
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sun4, from @file{aout32.c}:
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@example
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@example
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#define ARCH_SIZE 32
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#define ARCH_SIZE 32
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#include "aoutx.h"
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#include "aoutx.h"
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@end example
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@end example
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Which exports names:
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Which exports names:
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@example
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@example
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...
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...
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aout_32_canonicalize_reloc
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aout_32_canonicalize_reloc
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aout_32_find_nearest_line
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aout_32_find_nearest_line
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aout_32_get_lineno
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aout_32_get_lineno
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aout_32_get_reloc_upper_bound
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aout_32_get_reloc_upper_bound
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...
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...
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@end example
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@end example
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from @file{sunos.c}:
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from @file{sunos.c}:
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@example
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@example
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#define TARGET_NAME "a.out-sunos-big"
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#define TARGET_NAME "a.out-sunos-big"
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#define VECNAME sunos_big_vec
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#define VECNAME sunos_big_vec
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#include "aoutf1.h"
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#include "aoutf1.h"
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@end example
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@end example
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requires all the names from @file{aout32.c}, and produces the jump vector
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requires all the names from @file{aout32.c}, and produces the jump vector
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@example
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@example
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sunos_big_vec
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sunos_big_vec
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@end example
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@end example
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The file @file{host-aout.c} is a special case. It is for a large set
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The file @file{host-aout.c} is a special case. It is for a large set
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of hosts that use ``more or less standard'' a.out files, and
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of hosts that use ``more or less standard'' a.out files, and
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for which cross-debugging is not interesting. It uses the
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for which cross-debugging is not interesting. It uses the
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standard 32-bit a.out support routines, but determines the
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standard 32-bit a.out support routines, but determines the
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file offsets and addresses of the text, data, and BSS
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file offsets and addresses of the text, data, and BSS
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sections, the machine architecture and machine type, and the
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sections, the machine architecture and machine type, and the
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entry point address, in a host-dependent manner. Once these
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entry point address, in a host-dependent manner. Once these
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values have been determined, generic code is used to handle
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values have been determined, generic code is used to handle
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the object file.
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the object file.
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When porting it to run on a new system, you must supply:
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When porting it to run on a new system, you must supply:
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@example
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@example
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HOST_PAGE_SIZE
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HOST_PAGE_SIZE
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HOST_SEGMENT_SIZE
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HOST_SEGMENT_SIZE
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HOST_MACHINE_ARCH (optional)
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HOST_MACHINE_ARCH (optional)
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HOST_MACHINE_MACHINE (optional)
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HOST_MACHINE_MACHINE (optional)
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HOST_TEXT_START_ADDR
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HOST_TEXT_START_ADDR
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HOST_STACK_END_ADDR
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HOST_STACK_END_ADDR
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@end example
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@end example
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in the file @file{../include/sys/h-@var{XXX}.h} (for your host). These
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in the file @file{../include/sys/h-@var{XXX}.h} (for your host). These
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values, plus the structures and macros defined in @file{a.out.h} on
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values, plus the structures and macros defined in @file{a.out.h} on
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your host system, will produce a BFD target that will access
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your host system, will produce a BFD target that will access
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ordinary a.out files on your host. To configure a new machine
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ordinary a.out files on your host. To configure a new machine
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to use @file{host-aout.c}, specify:
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to use @file{host-aout.c}, specify:
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@example
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@example
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TDEFAULTS = -DDEFAULT_VECTOR=host_aout_big_vec
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TDEFAULTS = -DDEFAULT_VECTOR=host_aout_big_vec
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TDEPFILES= host-aout.o trad-core.o
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TDEPFILES= host-aout.o trad-core.o
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@end example
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@end example
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in the @file{config/@var{XXX}.mt} file, and modify @file{configure.in}
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in the @file{config/@var{XXX}.mt} file, and modify @file{configure.in}
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to use the
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to use the
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@file{@var{XXX}.mt} file (by setting "@code{bfd_target=XXX}") when your
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@file{@var{XXX}.mt} file (by setting "@code{bfd_target=XXX}") when your
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configuration is selected.
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configuration is selected.
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@subsection Relocations
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@subsection Relocations
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@strong{Description}@*
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@strong{Description}@*
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The file @file{aoutx.h} provides for both the @emph{standard}
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The file @file{aoutx.h} provides for both the @emph{standard}
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and @emph{extended} forms of a.out relocation records.
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and @emph{extended} forms of a.out relocation records.
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The standard records contain only an
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The standard records contain only an
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address, a symbol index, and a type field. The extended records
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address, a symbol index, and a type field. The extended records
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(used on 29ks and sparcs) also have a full integer for an
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(used on 29ks and sparcs) also have a full integer for an
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addend.
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addend.
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@subsection Internal entry points
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@subsection Internal entry points
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@strong{Description}@*
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@strong{Description}@*
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@file{aoutx.h} exports several routines for accessing the
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@file{aoutx.h} exports several routines for accessing the
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contents of an a.out file, which are gathered and exported in
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contents of an a.out file, which are gathered and exported in
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turn by various format specific files (eg sunos.c).
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turn by various format specific files (eg sunos.c).
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@findex aout_@var{size}_swap_exec_header_in
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@findex aout_@var{size}_swap_exec_header_in
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@subsubsection @code{aout_@var{size}_swap_exec_header_in}
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@subsubsection @code{aout_@var{size}_swap_exec_header_in}
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@strong{Synopsis}
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@strong{Synopsis}
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@example
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@example
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void aout_@var{size}_swap_exec_header_in,
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void aout_@var{size}_swap_exec_header_in,
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(bfd *abfd,
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(bfd *abfd,
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struct external_exec *bytes,
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struct external_exec *bytes,
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struct internal_exec *execp);
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struct internal_exec *execp);
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@end example
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@end example
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@strong{Description}@*
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@strong{Description}@*
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Swap the information in an executable header @var{raw_bytes} taken
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Swap the information in an executable header @var{raw_bytes} taken
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from a raw byte stream memory image into the internal exec header
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from a raw byte stream memory image into the internal exec header
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structure @var{execp}.
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structure @var{execp}.
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@findex aout_@var{size}_swap_exec_header_out
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@findex aout_@var{size}_swap_exec_header_out
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@subsubsection @code{aout_@var{size}_swap_exec_header_out}
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@subsubsection @code{aout_@var{size}_swap_exec_header_out}
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@strong{Synopsis}
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@strong{Synopsis}
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@example
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@example
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void aout_@var{size}_swap_exec_header_out
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void aout_@var{size}_swap_exec_header_out
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(bfd *abfd,
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(bfd *abfd,
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struct internal_exec *execp,
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struct internal_exec *execp,
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struct external_exec *raw_bytes);
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struct external_exec *raw_bytes);
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@end example
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@end example
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@strong{Description}@*
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@strong{Description}@*
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Swap the information in an internal exec header structure
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Swap the information in an internal exec header structure
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@var{execp} into the buffer @var{raw_bytes} ready for writing to disk.
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@var{execp} into the buffer @var{raw_bytes} ready for writing to disk.
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@findex aout_@var{size}_some_aout_object_p
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@findex aout_@var{size}_some_aout_object_p
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@subsubsection @code{aout_@var{size}_some_aout_object_p}
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@subsubsection @code{aout_@var{size}_some_aout_object_p}
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@strong{Synopsis}
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@strong{Synopsis}
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@example
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@example
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const bfd_target *aout_@var{size}_some_aout_object_p
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const bfd_target *aout_@var{size}_some_aout_object_p
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(bfd *abfd,
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(bfd *abfd,
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struct internal_exec *execp,
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struct internal_exec *execp,
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const bfd_target *(*callback_to_real_object_p) (bfd *));
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const bfd_target *(*callback_to_real_object_p) (bfd *));
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@end example
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@end example
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@strong{Description}@*
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@strong{Description}@*
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Some a.out variant thinks that the file open in @var{abfd}
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Some a.out variant thinks that the file open in @var{abfd}
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checking is an a.out file. Do some more checking, and set up
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checking is an a.out file. Do some more checking, and set up
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for access if it really is. Call back to the calling
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for access if it really is. Call back to the calling
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environment's "finish up" function just before returning, to
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environment's "finish up" function just before returning, to
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handle any last-minute setup.
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handle any last-minute setup.
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@findex aout_@var{size}_mkobject
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@findex aout_@var{size}_mkobject
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@subsubsection @code{aout_@var{size}_mkobject}
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@subsubsection @code{aout_@var{size}_mkobject}
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@strong{Synopsis}
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@strong{Synopsis}
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@example
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@example
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bfd_boolean aout_@var{size}_mkobject, (bfd *abfd);
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bfd_boolean aout_@var{size}_mkobject, (bfd *abfd);
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@end example
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@end example
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@strong{Description}@*
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@strong{Description}@*
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Initialize BFD @var{abfd} for use with a.out files.
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Initialize BFD @var{abfd} for use with a.out files.
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@findex aout_@var{size}_machine_type
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@findex aout_@var{size}_machine_type
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@subsubsection @code{aout_@var{size}_machine_type}
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@subsubsection @code{aout_@var{size}_machine_type}
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@strong{Synopsis}
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@strong{Synopsis}
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@example
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@example
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enum machine_type aout_@var{size}_machine_type
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enum machine_type aout_@var{size}_machine_type
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(enum bfd_architecture arch,
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(enum bfd_architecture arch,
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unsigned long machine,
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unsigned long machine,
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bfd_boolean *unknown);
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bfd_boolean *unknown);
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@end example
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@end example
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@strong{Description}@*
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@strong{Description}@*
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Keep track of machine architecture and machine type for
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Keep track of machine architecture and machine type for
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a.out's. Return the @code{machine_type} for a particular
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a.out's. Return the @code{machine_type} for a particular
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architecture and machine, or @code{M_UNKNOWN} if that exact architecture
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architecture and machine, or @code{M_UNKNOWN} if that exact architecture
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and machine can't be represented in a.out format.
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and machine can't be represented in a.out format.
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If the architecture is understood, machine type 0 (default)
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If the architecture is understood, machine type 0 (default)
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is always understood.
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is always understood.
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@findex aout_@var{size}_set_arch_mach
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@findex aout_@var{size}_set_arch_mach
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@subsubsection @code{aout_@var{size}_set_arch_mach}
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@subsubsection @code{aout_@var{size}_set_arch_mach}
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@strong{Synopsis}
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@strong{Synopsis}
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@example
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@example
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bfd_boolean aout_@var{size}_set_arch_mach,
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bfd_boolean aout_@var{size}_set_arch_mach,
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(bfd *,
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(bfd *,
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enum bfd_architecture arch,
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enum bfd_architecture arch,
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unsigned long machine);
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unsigned long machine);
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@end example
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@end example
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@strong{Description}@*
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@strong{Description}@*
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Set the architecture and the machine of the BFD @var{abfd} to the
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Set the architecture and the machine of the BFD @var{abfd} to the
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values @var{arch} and @var{machine}. Verify that @var{abfd}'s format
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values @var{arch} and @var{machine}. Verify that @var{abfd}'s format
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can support the architecture required.
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can support the architecture required.
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@findex aout_@var{size}_new_section_hook
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@findex aout_@var{size}_new_section_hook
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@subsubsection @code{aout_@var{size}_new_section_hook}
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@subsubsection @code{aout_@var{size}_new_section_hook}
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@strong{Synopsis}
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@strong{Synopsis}
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@example
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@example
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bfd_boolean aout_@var{size}_new_section_hook,
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bfd_boolean aout_@var{size}_new_section_hook,
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(bfd *abfd,
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(bfd *abfd,
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asection *newsect);
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asection *newsect);
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@end example
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@end example
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@strong{Description}@*
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@strong{Description}@*
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Called by the BFD in response to a @code{bfd_make_section}
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Called by the BFD in response to a @code{bfd_make_section}
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request.
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request.
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