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Diffstat (limited to 'bfd/PORTING')
| -rw-r--r-- | bfd/PORTING | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/bfd/PORTING b/bfd/PORTING new file mode 100644 index 0000000..c8bfd77 --- /dev/null +++ b/bfd/PORTING @@ -0,0 +1,83 @@ + 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.in 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.in, 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>" |