1 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 <host>. 11 (<host> might be sun4, ...) 12 Create a file hosts/<host>.mh. 13 14 Porting to a new target 15 ----------------------- 16 Pick a name for your target. Call that <target>. 17 Call the name for your CPU architecture <cpu>. 18 You need to create <target>.c and config/<target>.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.ac which associates each target vector with 23 the .o files it uses. 24 25 config/<target>.mt is a Makefile fragment. 26 The following is usually enough: 27 DEFAULT_VECTOR=<target>_vec 28 SELECT_ARCHITECTURES=bfd_<cpu>_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.ac, and binutils/objdump.c. 33 34 For more information about .mt and .mh files, see config/README. 35 36 The file <target>.c is the hard part. It implements the 37 bfd_target <target>_vec, which includes pointers to 38 functions that do the actual <target>-specific methods. 39 40 Porting to a <target> 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 <target>.c for 45 you 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"). 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 <target>.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 <target> 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-<target>" 84 86 Copyright (C) 2012-2016 Free Software Foundation, Inc. 87 88 Copying and distribution of this file, with or without modification, 89 are permitted in any medium without royalty provided the copyright 90 notice and this notice are preserved. 91
