dis88(9) [minix man page]
Dis88 disassembles 8088 object code to the assembly language for- mat used by It makes full use of symbol table information, sup- ports separate instruction and data space, and generates synthet- ic labels when needed. It does not support 8087 mnemonics, sym- bolic data segment references, or the ESC mnemonic. The program is invoked by: The -o flag causes object code to be listed. If no outfile is given, stdout is used. The text segment of an ob- ject file is always padded to an even address. In addition, if the file has split I/D space, the text segment will be padded to a paragraph boundary (i.e., an address divisible by 16). Due to padding, the disassembler may produce a few spurious, but harm- less, instructions at the end of the text segment. Because the information to which initialized data refers cannot generally be inferred from context, the data segment is treated literally. Byte values (in hexadecimal) are output, and long stretches of null data are represented by appropriate .zerow pseudo-ops. Dis- assembly of the bss segment, on the other hand, is quite straightforward, because uninitialized data is all zero by defi- nition. No data is output in the bss segment, but symbolic la- bels are output as appropriate. The output of operands in sym- bolic form is complicated somewhat by the existence of assembler symbolic constants and segment override opcodes. Thus, the pro- gram's symbol lookup routine attempts to apply a certain amount of intelligence when it is asked to find a symbol. If it cannot match on a symbol of the preferred type, it may output a symbol of some other type, depending on preassigned (and somewhat arbi- trary) rankings within each type. Finally, if all else fails, it will output a string containing the address sought as a hex con- stant. For user convenience, the targets of branches are also output, in comments, as hexadecimal constants. Various error messages may be generated as a result of problems encountered during the disassembly. They are listed below Cannot access input file - Input file cannot be opened or read Cannot open output file - Output file cannot be created Input file not in object format-Bad magic number Not an 8086/8088 object file -CPU ID of the file header is in- correct Reloc table overflow - Relocation table exceeds 1500 en- tries Symbol table overflow - Symbol table exceeds 1500 entries Lseek error - Input file corrupted (should nev- er happen) Warning: no symbols - Symbol table is missing (use ast) Cannot reopen input file - Input file was removed during ex- ecution Dis88 was written and copyrighted by G. M. Harding and is in- cluded here by permission. It may be freely redistributed provid- ed that complete source code, with all copyright notices, accom- panies any redistribution. This provision also applies to any modifications you may make. You are urged to comment such changes, giving, as a minimum, your name and complete address.
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ld86(1) General Commands Manual ld86(1) NAME
ld86 - Linker for as86(1) SYNOPSIS
ld86 [-03MNdimrstyz[-]] [-llib_extension] [-o outfile] [-Ccrtfile] [-Llibdir] [-Olibfile] [-Ttextaddr] [-Hheapsize] [-Ddataaddr] infile... DESCRIPTION
This linker understands only the object files produced by the as86 assembler, it can link them into either an impure or a separate I&D executable. The linking defaults are everything off or none except for -0 and the output file is a.out. There is not a standard library location defined in the linker. OPTIONS
-0 produce header with 16-bit magic -3 produce header with 32-bit magic -d delete the header from the output file, used for MSDOS COM files. As a side effect this also includes -s as there's nowhere to put a symbol table. -Cx add file libdir-from-search/crtx.o to list of files linked -D data base address follows (in format suitable for strtoul) -H the top of heap (initial stack) address (in format suitable for strtoul) -Lx add dir name x to the head of the list of library dirs searched -M print symbols linked on stdout -N Create a native Linux OMAGIC output file. If the contents are i386 code the binary can be either linked by GCC or executed by linux. If the -z option is also included the linker can generate a QMAGIC executable. -Ox add library or object file libdir-from-search/x to list of files linked -T text base address follows (in format suitable for strtoul) -i separate I&D output -lx add library libdir-from-search/libx.a to list of files linked -m print modules linked on stdout -o output file name follows -s strip symbols -r Generate a relocatable object from one source object, if the linker is given the -N option also the output format will be the hosts native format if possible. -t trace modules being looked at on stdout -y Alter the symbol tables to add label 'extensions' so that labels with more than 8 characters can be stored in elks executables. -z produce "unmapped zero page" or "QMAGIC" executables All the options not taking an argument may be turned off by following the option letter by a '-', as for cc1. PREDEFINED LABELS
The linker predefines several labels that can be imported into user programs. __etext Standard C variable for the end of the text segment. __edata Standard C variable for the end of the initilised data. __end Standard C variable for the end of the bss area. __segoff The offset within the executable file between the start of the text segment and the start of the data segment in 16 byte 'paragraphs'. Note this is zero for impure (tiny model) executables and is adjusted for executables that don't start at offset 0 within the segment. __segXDL The lowest address with data in segment 'X'. (eg __seg0DL is for segment zero or the text segment, __seg3DL is for the data segment) The value 'X' is a hex digit. __segXDH The top of segment 'X's data area. __segXCL The bottom of segment 'X's 'common data' or unitilised data area. Each segment has both an initilised and unitilised data area. __segXCH The top of segment 'X's common area. __segXSO This is the adjusted offset from segment 0 of the start of segment 'X' in 'paragraphs'. HISTORY
The 6809 version does not support -i. The previous versions of the linker could produce an 8086 executable with segments of a size >64k, now only i386 executables may have segments this large. BUGS
The linker cannot deal with reverse seeks caused by org instructions in the object file. Unlike previous versions the current one traps the error rather than trying to fill up the hard disk. The linker produces a broken a.out object file if given one input and the -r option this is so it is compatible with pre-dev86 versions. Apr, 1997 ld86(1)