PORTING revision 302408
1 Preliminary Notes on Porting BFD 2 -------------------------------- 3 4The 'host' is the system a tool runs *on*. 5The 'target' is the system a tool runs *for*, i.e. 6a tool can read/write the binaries of the target. 7 8Porting to a new host 9--------------------- 10Pick a name for your host. Call that <host>. 11(<host> might be sun4, ...) 12Create a file hosts/<host>.mh. 13 14Porting to a new target 15----------------------- 16Pick a name for your target. Call that <target>. 17Call the name for your CPU architecture <cpu>. 18You need to create <target>.c and config/<target>.mt, 19and add a case for it to a case statements in bfd/configure.host and 20bfd/config.bfd, which associates each canonical host type with a BFD 21host type (used as the base of the makefile fragment names), and to the 22table in bfd/configure.in which associates each target vector with 23the .o files it uses. 24 25config/<target>.mt is a Makefile fragment. 26The following is usually enough: 27DEFAULT_VECTOR=<target>_vec 28SELECT_ARCHITECTURES=bfd_<cpu>_arch 29 30See the list of cpu types in archures.c, or "ls cpu-*.c". 31If your architecture is new, you need to add it to the tables 32in bfd/archures.c, opcodes/configure.in, and binutils/objdump.c. 33 34For more information about .mt and .mh files, see config/README. 35 36The file <target>.c is the hard part. It implements the 37bfd_target <target>_vec, which includes pointers to 38functions that do the actual <target>-specific methods. 39 40Porting to a <target> that uses the a.out binary format 41------------------------------------------------------- 42 43In this case, the include file aout-target.h probaby does most 44of what you need. The program gen-aout generates <target>.c for 45you automatically for many a.out systems. Do: 46 make gen-aout 47 ./gen-aout <target> > <target>.c 48(This only works if you are building on the target ("native"). 49If you must make a cross-port from scratch, copy the most 50similar existing file that includes aout-target.h, and fix what is wrong.) 51 52Check the parameters in <target>.c, and fix anything that is wrong. 53(Also let us know about it; perhaps we can improve gen-aout.c.) 54 55TARGET_IS_BIG_ENDIAN_P 56 Should be defined if <target> is big-endian. 57 58N_HEADER_IN_TEXT(x) 59 See discussion in ../include/aout/aout64.h. 60 61BYTES_IN_WORD 62 Number of bytes per word. (Usually 4 but can be 8.) 63 64ARCH 65 Number of bits per word. (Usually 32, but can be 64.) 66 67ENTRY_CAN_BE_ZERO 68 Define if the extry point (start address of an 69 executable program) can be 0x0. 70 71TEXT_START_ADDR 72 The address of the start of the text segemnt in 73 virtual memory. Normally, the same as the entry point. 74 75TARGET_PAGE_SIZE 76 77SEGMENT_SIZE 78 Usually, the same as the TARGET_PAGE_SIZE. 79 Alignment needed for the data segment. 80 81TARGETNAME 82 The name of the target, for run-time lookups. 83 Usually "a.out-<target>" 84