| 1 |
14 |
khays |
Preliminary Notes on Porting BFD
|
| 2 |
|
|
--------------------------------
|
| 3 |
|
|
|
| 4 |
|
|
The 'host' is the system a tool runs *on*.
|
| 5 |
|
|
The 'target' is the system a tool runs *for*, i.e.
|
| 6 |
|
|
a tool can read/write the binaries of the target.
|
| 7 |
|
|
|
| 8 |
|
|
Porting to a new host
|
| 9 |
|
|
---------------------
|
| 10 |
|
|
Pick a name for your host. Call that .
|
| 11 |
|
|
( might be sun4, ...)
|
| 12 |
|
|
Create a file hosts/.mh.
|
| 13 |
|
|
|
| 14 |
|
|
Porting to a new target
|
| 15 |
|
|
-----------------------
|
| 16 |
|
|
Pick a name for your target. Call that .
|
| 17 |
|
|
Call the name for your CPU architecture .
|
| 18 |
|
|
You need to create .c and config/.mt,
|
| 19 |
|
|
and add a case for it to a case statements in bfd/configure.host and
|
| 20 |
|
|
bfd/config.bfd, which associates each canonical host type with a BFD
|
| 21 |
|
|
host type (used as the base of the makefile fragment names), and to the
|
| 22 |
|
|
table in bfd/configure.in which associates each target vector with
|
| 23 |
|
|
the .o files it uses.
|
| 24 |
|
|
|
| 25 |
|
|
config/.mt is a Makefile fragment.
|
| 26 |
|
|
The following is usually enough:
|
| 27 |
|
|
DEFAULT_VECTOR=_vec
|
| 28 |
|
|
SELECT_ARCHITECTURES=bfd__arch
|
| 29 |
|
|
|
| 30 |
|
|
See the list of cpu types in archures.c, or "ls cpu-*.c".
|
| 31 |
|
|
If your architecture is new, you need to add it to the tables
|
| 32 |
|
|
in bfd/archures.c, opcodes/configure.in, and binutils/objdump.c.
|
| 33 |
|
|
|
| 34 |
|
|
For more information about .mt and .mh files, see config/README.
|
| 35 |
|
|
|
| 36 |
|
|
The file .c is the hard part. It implements the
|
| 37 |
|
|
bfd_target _vec, which includes pointers to
|
| 38 |
|
|
functions that do the actual -specific methods.
|
| 39 |
|
|
|
| 40 |
|
|
Porting to a that uses the a.out binary format
|
| 41 |
|
|
-------------------------------------------------------
|
| 42 |
|
|
|
| 43 |
|
|
In this case, the include file aout-target.h probaby does most
|
| 44 |
|
|
of what you need. The program gen-aout generates .c for
|
| 45 |
|
|
you automatically for many a.out systems. Do:
|
| 46 |
|
|
make gen-aout
|
| 47 |
|
|
./gen-aout > .c
|
| 48 |
|
|
(This only works if you are building on the target ("native").
|
| 49 |
|
|
If you must make a cross-port from scratch, copy the most
|
| 50 |
|
|
similar existing file that includes aout-target.h, and fix what is wrong.)
|
| 51 |
|
|
|
| 52 |
|
|
Check the parameters in .c, and fix anything that is wrong.
|
| 53 |
|
|
(Also let us know about it; perhaps we can improve gen-aout.c.)
|
| 54 |
|
|
|
| 55 |
|
|
TARGET_IS_BIG_ENDIAN_P
|
| 56 |
|
|
Should be defined if is big-endian.
|
| 57 |
|
|
|
| 58 |
|
|
N_HEADER_IN_TEXT(x)
|
| 59 |
|
|
See discussion in ../include/aout/aout64.h.
|
| 60 |
|
|
|
| 61 |
|
|
BYTES_IN_WORD
|
| 62 |
|
|
Number of bytes per word. (Usually 4 but can be 8.)
|
| 63 |
|
|
|
| 64 |
|
|
ARCH
|
| 65 |
|
|
Number of bits per word. (Usually 32, but can be 64.)
|
| 66 |
|
|
|
| 67 |
|
|
ENTRY_CAN_BE_ZERO
|
| 68 |
|
|
Define if the extry point (start address of an
|
| 69 |
|
|
executable program) can be 0x0.
|
| 70 |
|
|
|
| 71 |
|
|
TEXT_START_ADDR
|
| 72 |
|
|
The address of the start of the text segemnt in
|
| 73 |
|
|
virtual memory. Normally, the same as the entry point.
|
| 74 |
|
|
|
| 75 |
|
|
TARGET_PAGE_SIZE
|
| 76 |
|
|
|
| 77 |
|
|
SEGMENT_SIZE
|
| 78 |
|
|
Usually, the same as the TARGET_PAGE_SIZE.
|
| 79 |
|
|
Alignment needed for the data segment.
|
| 80 |
|
|
|
| 81 |
|
|
TARGETNAME
|
| 82 |
|
|
The name of the target, for run-time lookups.
|
| 83 |
|
|
Usually "a.out-"
|
