89 lines
3 KiB
Text
89 lines
3 KiB
Text
Preliminary Notes on Porting BFD
|
||
--------------------------------
|
||
|
||
The 'host' is the system a tool runs *on*.
|
||
The 'target' is the system a tool runs *for*, i.e.
|
||
a tool can read/write the binaries of the target.
|
||
|
||
Porting to a new host
|
||
---------------------
|
||
Pick a name for your host. Call that <host>.
|
||
(<host> might be sun4, ...)
|
||
Create a file hosts/<host>.mh.
|
||
|
||
Porting to a new target
|
||
-----------------------
|
||
Pick a name for your target. Call that <target>.
|
||
Call the name for your CPU architecture <cpu>.
|
||
You need to create <target>.c and config/<target>.mt,
|
||
and add a case for it to a case statements in bfd/configure.host and
|
||
bfd/config.bfd, which associates each canonical host type with a BFD
|
||
host type (used as the base of the makefile fragment names), and to the
|
||
table in bfd/configure.ac which associates each target vector with
|
||
the .o files it uses.
|
||
|
||
config/<target>.mt is a Makefile fragment.
|
||
The following is usually enough:
|
||
DEFAULT_VECTOR=<target>_vec
|
||
SELECT_ARCHITECTURES=bfd_<cpu>_arch
|
||
|
||
See the list of cpu types in archures.c, or "ls cpu-*.c".
|
||
If your architecture is new, you need to add it to the tables
|
||
in bfd/archures.c, opcodes/configure.ac, and binutils/objdump.c.
|
||
|
||
For more information about .mt and .mh files, see config/README.
|
||
|
||
The file <target>.c is the hard part. It implements the
|
||
bfd_target <target>_vec, which includes pointers to
|
||
functions that do the actual <target>-specific methods.
|
||
|
||
Porting to a <target> that uses the a.out binary format
|
||
-------------------------------------------------------
|
||
|
||
In this case, the include file aout-target.h probaby does most
|
||
of what you need. The program gen-aout generates <target>.c for
|
||
you automatically for many a.out systems. Do:
|
||
make gen-aout
|
||
./gen-aout <target> > <target>.c
|
||
(This only works if you are building on the target ("native").
|
||
If you must make a cross-port from scratch, copy the most
|
||
similar existing file that includes aout-target.h, and fix what is wrong.)
|
||
|
||
Check the parameters in <target>.c, and fix anything that is wrong.
|
||
(Also let us know about it; perhaps we can improve gen-aout.c.)
|
||
|
||
TARGET_IS_BIG_ENDIAN_P
|
||
Should be defined if <target> is big-endian.
|
||
|
||
N_HEADER_IN_TEXT(x)
|
||
See discussion in ../include/aout/aout64.h.
|
||
|
||
BYTES_IN_WORD
|
||
Number of bytes per word. (Usually 4 but can be 8.)
|
||
|
||
ARCH
|
||
Number of bits per word. (Usually 32, but can be 64.)
|
||
|
||
ENTRY_CAN_BE_ZERO
|
||
Define if the extry point (start address of an
|
||
executable program) can be 0x0.
|
||
|
||
TEXT_START_ADDR
|
||
The address of the start of the text segemnt in
|
||
virtual memory. Normally, the same as the entry point.
|
||
|
||
TARGET_PAGE_SIZE
|
||
|
||
SEGMENT_SIZE
|
||
Usually, the same as the TARGET_PAGE_SIZE.
|
||
Alignment needed for the data segment.
|
||
|
||
TARGETNAME
|
||
The name of the target, for run-time lookups.
|
||
Usually "a.out-<target>"
|
||
|
||
Copyright (C) 2012-2016 Free Software Foundation, Inc.
|
||
|
||
Copying and distribution of this file, with or without modification,
|
||
are permitted in any medium without royalty provided the copyright
|
||
notice and this notice are preserved.
|