| 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) 2012-2023 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. |