CHANGES   [plain text]

* fix (?) bug in outobj.c - every 256th "extern" caused Nasm crash

* fix buffer overflow
* fix outas86's .bss handling
* "make spotless" no longer deletes
* %(el)if(n)idn insensitivity to string quotes difference (#809300).
* (nasm.c) __OUTPUT_FORMAT__ changed to string value instead of symbol.

* Add Makefile for 16-bit DOS binaries under OpenWatcom, and modify to be able to generate completely pathless dependencies, as
  required by OpenWatcom wmake (it supports path searches, but not
  explicit paths.)
* Fix the STR instruction.
* Fix the ELF output format, which was broken under certain
  circumstances due to the addition of stabs support.
* Quick-fix Borland format debug-info for -f obj  
* Fix for %rep with no arguments (#560568)
* Fix concatenation of preprocessor function call (#794686)
* Fix long label causes coredump (#677841)
* Use autoheader as well as autoconf to keep configure from generating
  ridiculously long command lines.
* Make sure that all of the formats which support debugging output
  actually will suppress debugging output when -g not specified.

* Paths given in "-I" switch searched for "incbin"ed as
  well as "%include"ed files.
* Added stabs debugging for the ELF output format, patch from
  Martin Wawro.
* Fix output/outbin.c to allow origin > 80000000h.
* Make -U switch work.
* Fix the use of relative offsets with explicit prefixes, e.g. "a32 loop foo".
* Remove "backslash()".
* Fix the SMSW and SLDT instructions.
* -O2 and -O3 are no longer aliases for -O10 and -O15.  If you mean the
  latter, please say so! :)

* Update rdoff - librarian/archiver - common rec - docs!
* Fix signed/unsigned problems.
* Fix JMP FAR label and CALL FAR label.
* Add new multisection support - map files - fix align bug
* Fix sysexit, movhps/movlps reg,reg bugs in insns.dat
* "Q" or "O" suffixes indicate octal
* Support Prescott new instructions (PNI).
* Cyrix XSTORE instruction.

* Fix build failure on 16-bit DOS (Makefile.bc3 workaround for compiler bug.)
* Fix dependencies and compiler warnings.
* Add "const" in a number of places.
* Add -X option to specify error reporting format (use -Xvc to
  integrate with Microsoft Visual Studio.)
* Minor changes for code legibility.
* Drop use of tmpnam() in rdoff (security fix.)

* Correct additional address-size vs. operand-size confusions.
* Generate dependencies for all Makefiles automatically.
* Add support for unimplemented (but theoretically available)
  registers such as tr0 and cr5.  Segment registers 6 and 7 are called
  segr6 and segr7 for the operations which they can be represented.
* Correct some disassembler bugs related to redundant address-size prefixes.
  Some work still remains in this area.
* Correctly generate an error for things like "SEG eax".
* Add the JMPE instruction, enabled by "CPU IA64".
* Correct compilation on newer gcc/glibc platforms.
* Issue an error on things like "jmp far eax".


* New __NASM_PATCHLEVEL__ and __NASM_VERSION_ID__ standard macros to
  round out the version-query macros. now understands
  X.YYplWW or X.YY.ZZplWW as a version number, equivalent to
  X.YY.ZZ.WW (or X.YY.0.WW, as appropriate).
* New keyword "strict" to disable the optimization of specific
* Fix the handing of size overrides with JMP instructions
  (instructions such as "jmp dword foo".)
* Fix the handling of "ABSOLUTE label", where "label" points into a
  relocatable segment.
* Fix OBJ output format with lots of externs.
* More documentation updates.
* Add -Ov option to get verbose information about optimizations.
* Undo a braindead change which broke %elif directives.
* Makefile updates.


* Fix NASM crashing when %macro directives were left unterminated.
* Lots of documentation updates.
* Complete rewrite of the PostScript/PDF documentation generator.
* The MS Visual C++ Makefile was updated and corrected.
* Recognize .rodata as a standard section name in ELF.
* Fix some obsolete Perl4-isms in Perl scripts.
* Fix to work with autoconf 2.5x.
* Fix a couple of "make cleaner" misses.
* Make the normal "./configure && make" work with Cygwin.


* Correctly build in a separate object directory again.
* Derive all references to the version number from the version file.
* New standard macros __NASM_SUBMINOR__ and __NASM_VER__ macros.
* Lots of Makefile updates and bug fixes.
* New %ifmacro directive to test for multiline macros.
* Documentation updates.
* Fixes for 16-bit OBJ format output.
* Changed the NASM environment variable to NASMENV.


* Changed doc files a lot: completely removed old READMExx and
  Wishlist files, incorporating all information in CHANGES and TODO.
* I waited a long time to rename zoutieee.c to (original) outieee.c
* moved all output modules to output/ subdirectory.
* Added 'make strip' target to strip debug info from nasm & ndisasm.
* Added INSTALL file with installation instructions.
* Added -v option description to nasm man.
* Added dist makefile target to produce source distributions.
* 16-bit support for ELF output format (GNU extension, but useful.)


* Fastcooked this for Debian's Woody release:
Frank applied the INCBIN bug patch to 0.98.25alt and called
it 0.98.28 to not confuse poor little apt-get.


* Reorganised files even better from 0.98.25alt


* Prettified the source tree. Moved files to more reasonable places.
* Added script to misc/ directory.
* Attempted to fix doc.


* Line continuation character '\'
* Docs inadvertantly reverted - "dos packaging".


* FIXME: Someone, document this please.


* Documentation - Ndisasm doc added to Nasm.doc.


* Attempted to remove rdoff version1
* Lino Mastrodomenico's patches to preproc.c (%$$ bug?).


* Update rdoff2 - attempt to remove v1.


* Optimization fixes.


* Optimization fixes.


* H. J. Lu's patch back out.


* Added ".rdata" to "-f win32".


* H. J. Lu's "bogus elf" patch. (Red Hat problem?)


* Fix whitespace before "[section ..." bug.


* Rdoff changes (?).
* Fix fixes to memory leaks.


* Fix memory leaks.
* (there was no '.13)


* Update optimization (new function of "-O1")
* Changes to test/bintest.asm (?).


* Optimization changes.
* Ndisasm fixed.
* (there was no '.10)


* Add multiple sections support to "-f bin".
* Changed GLOBAL_TEMP_BASE in outelf.c from 6 to 15.
* Add "-v" as an alias to the "-r" switch.
* Remove "#ifdef" from Tasm compatibility options.
* Remove redundant size-overrides on "mov ds, ex", etc.
* Fixes to SSE2, other insns.dat (?).
* Enable uppercase "I" and "P" switches.
* Case insinsitive "seg" and "wrt".
* Update (?).
* Allocate tokens in blocks.
* Improve "invalid effective address" messages.


* Add "%strlen" and "%substr" macro operators
* Fixed broken c16.mac.
* Unterminated string error reported.
* Fixed bugs as per 0.98bf

0.98.09b with John Coffman patches released 28-Oct-2001

Changes from 0.98.07 release to 98.09b as of 28-Oct-2001

* More closely compatible with 0.98 when -O0 is implied
or specified.  Not strictly identical, since backward 
branches in range of short offsets are recognized, and signed
byte values with no explicit size specification will be
assembled as a single byte.

* More forgiving with the PUSH instruction.  0.98 requires
a size to be specified always.  0.98.09b will imply the size
from the current BITS setting (16 or 32).

* Changed definition of the optimization flag:

	-O0	strict two-pass assembly, JMP and Jcc are
		handled more like 0.98, except that back-
		ward JMPs are short, if possible.

	-O1	strict two-pass assembly, but forward
		branches are assembled with code guaranteed
		to reach; may produce larger code than
		-O0, but will produce successful assembly
		more often if branch offset sizes are not

	-O2	multi-pass optimization, minimize branch
		offsets; also will minimize signed immed-
		iate bytes, overriding size specification.

	-O3	like -O2, but more passes taken, if needed

0.98.07 released 01/28/01

*       Added Stepane Denis' SSE2 instructions to a *working*
        version of the code - some earlier versions were based on
        broken code - sorry 'bout that. version "0.98.07"


*       Cosmetic modifications to nasm.c, nasm.h,

0.98.06f released 01/18/01

*       - Add "metalbrain"s jecxz bug fix in insns.dat
        - alter nasmdoc.src to match - version "0.98.06f"

0.98.06e released 01/09/01

*       Removed the "outforms.h" file - it appears to be
        someone's old backup of "outform.h". version "0.98.06e" 


* fbk - finally added the fix for the "multiple %includes bug",
        known since 7/27/99 - reported originally (?) and sent to
        us by Austin Lunnen - he reports that John Fine had a fix
        within the day. Here it is...

* Nelson Rush resigns from the group. Big thanks to Nelson for
  his leadership and enthusiasm in getting these changes
  incorporated into Nasm!

* fbk - [list +], [list -] directives - ineptly implemented, should
        be re-written or removed, perhaps.

* Brian Raiter / fbk - "elfso bug" fix - applied to aoutb format
                       as well - testing might be desirable...


* James Seter - -postfix, -prefix command line switches.
* Yuri Zaporogets - rdoff utility changes.


* GAS-like palign (Panos Minos)
* FIXME: Someone, fill this in with details

0.98bf (bug-fixed)

* Fixed - elf and aoutb bug - shared libraries
        - multiple "%include" bug in "-f obj"   
        - jcxz, jecxz bug
	- unrecognized option bug in ndisasm 

0.98.03 with John Coffman's changes released 27-Jul-2000

* Added signed byte optimizations for the 0x81/0x83 class
of instructions: ADC, ADD, AND, CMP, OR, SBB, SUB, XOR:
when used as 'ADD reg16,imm' or 'ADD reg32,imm.'  Also
optimization of signed byte form of 'PUSH imm' and 'IMUL
reg,imm'/'IMUL reg,reg,imm.'  No size specification is needed.

* Added multi-pass JMP and Jcc offset optimization.  Offsets
on forward references will preferentially use the short form,
without the need to code a specific size (short or near) for
the branch.  Added instructions for 'Jcc label' to use the
form 'Jnotcc $+3/JMP label', in cases where a short offset
is out of bounds.  If compiling for a 386 or higher CPU, then
the 386 form of Jcc will be used instead.

This feature is controlled by a new command-line switch: "O",
(upper case letter O).  "-O0" reverts the assembler to no
extra optimization passes, "-O1" allows up to 5 extra passes,
and "-O2"(default), allows up to 10 extra optimization passes.

* Added a new directive:  'cpu XXX', where XXX is any of: 
8086, 186, 286, 386, 486, 586, pentium, 686, PPro, P2, P3 or
Katmai.  All are case insensitive.  All instructions will
be selected only if they apply to the selected cpu or lower.
Corrected a couple of bugs in cpu-dependence in 'insns.dat'.

* Added to 'standard.mac', the "use16" and "use32" forms of
the "bits 16/32" directive. This is nothing new, just conforms
to a lot of other assemblers. (minor)

* Changed label allocation from 320/32 (10000 labels @ 200K+) 
to 32/37 (1000 labels); makes running under DOS much easier.
Since additional label space is allocated dynamically, this
should have no effect on large programs with lots of labels.
The 37 is a prime, believed to be better for hashing. (minor)

* Integrated patchfile 0.98-0.98.01.  I call this version
0.98.03, for historical reasons:  0.98.02 was trashed.

--John Coffman <>               27-Jul-2000

Kendall Bennett's SciTech MGL changes
Note that you must define "TASM_COMPAT" at compile-time
to get the Tasm Ideal Mode compatibility.

All changes can be compiled in and out using the TASM_COMPAT macros,
and when compiled without TASM_COMPAT defined we get the exact same
binary as the unmodified 0.98 sources.

standard.mac, macros.c:
 . Added macros to ignore TASM directives before first include

 . Added extern declaration for tasm_compatible_mode

 . Added global variable tasm_compatible_mode
 . Added command line switch for TASM compatible mode (-t)
 . Changed version command line to reflect when compiled with TASM additions
 . Added response file processing to allow all arguments on a single
   line (response file is @resp rather than -@resp for NASM format).

 . Changes islocal() macro to support TASM style @@local labels.
 . Added islocalchar() macro to support TASM style @@local labels.

 . Added support for TASM style memory references (ie: mov [DWORD eax],10
   rather than the NASM style mov DWORD [eax],10).

 . Added new directives, %arg, %local, %stacksize to directives table
 . Added support for TASM style directives without a leading % symbol.

Integrated a block of changes from Andrew Zabolotny <>:

* A new keyword %xdefine and its case-insensitive counterpart %ixdefine.
    They work almost the same way as %define and %idefine but expand
    the definition immediately, not on the invocation. Something like a cross
    between %define and %assign. The "x" suffix stands for "eXpand", so
    "xdefine" can be deciphered as "expand-and-define". Thus you can do
    things like this:

	%assign ofs	0
	%macro	arg	1
		%xdefine %1 dword [esp+ofs]
		%assign ofs ofs+4

* Changed the place where the expansion of %$name macros are expanded.
    Now they are converted into form when detokenizing, so
    there are no quirks as before when using %$name arguments to macros,
    in macros etc. For example:

	%macro	abc	1
		%define	%1 hello

	abc	%$here

    Now last line will be expanded into "hello" as expected. This also allows
    for lots of goodies, a good example are extended "proc" macros included
    in this archive.

* Added a check for "cstk" in smacro_defined() before calling get_ctx() -
    this allows for things like:

	%ifdef %$abc

    to work without warnings even in no context.

* Added a check for "cstk" in %if*ctx and %elif*ctx directives -
    this allows to use %ifctx without excessive warnings. If there is
    no active context, %ifctx goes through "false" branch.

* Removed "user error: " prefix with %error directive: it just clobbers the
    output and has absolutely no functionality. Besides, this allows to write
    macros that does not differ from built-in functions in any way.

* Added expansion of string that is output by %error directive. Now you
    can do things like:

	%define hello(x) Hello, x!

	%define %$name andy
	%error "hello(%$name)"

    Same happened with %include directive.

* Now all directives that expect an identifier will try to expand and
    concatenate everything without whitespaces in between before usage.
    For example, with "unfixed" nasm the commands

	%define %$abc hello
	%define __%$abc goodbye

    would produce "incorrect" output: last line will expand to

	hello goodbyehello

    Not quite what you expected, eh? :-) The answer is that preprocessor
    treats the %define construct as if it would be

	%define __ %$abc goodbye

    (note the white space between __ and %$abc). After my "fix" it
    will "correctly" expand into


    as expected. Note that I use quotes around words "correct", "incorrect"
    etc because this is rather a feature not a bug; however current behaviour
    is more logical (and allows more advanced macro usage :-).

    Same change was applied to:

* A new directive [WARNING {+|-}warning-id] have been added. It works only
    if the assembly phase is enabled (i.e. it doesn't work with nasm -e).

* A new warning type: macro-selfref. By default this warning is disabled;
    when enabled NASM warns when a macro self-references itself; for example
    the following source:

	[WARNING macro-selfref]

	%macro		push	1-*
		%rep	%0
			push	%1
			%rotate	1

			push	eax,ebx,ecx

    will produce a warning, but if we remove the first line we won't see it
    anymore (which is The Right Thing To Do {tm} IMHO since C preprocessor
    eats such constructs without warnings at all).

* Added a "error" routine to preprocessor which always will set ERR_PASS1
    bit in severity_code. This removes annoying repeated errors on first
    and second passes from preprocessor.

* Added the %+ operator in single-line macros for concatenating two
    identifiers. Usage example:

	%define _myfunc _otherfunc
	%define cextern(x) _ %+ x
	cextern (myfunc)

    After first expansion, third line will become "_myfunc". After this
    expansion is performed again so it becomes "_otherunc".

* Now if preprocessor is in a non-emmitting state, no warning or error
    will be emmitted. Example:

	%if 1
		mov	eax,ebx
		put anything you want between these two brackets,
		even macro-parameter references %1 or local labels %$zz
		or macro-local labels %%zz - no warning will be emmitted.

* Context-local variables on expansion as a last resort are looked up
    in outer contexts. For example, the following piece:

	%push	outer
	%define	%$a [esp]

		%push	inner

    will expand correctly the fourth line to [esp]; if we'll define another
    %$a inside the "inner" context, it will take precedence over outer
    definition. However, this modification has been applied only to
    expand_smacro and not to smacro_define: as a consequence expansion
    looks in outer contexts, but %ifdef won't look in outer contexts.

    This behaviour is needed because we don't want nested contexts to
    act on already defined local macros. Example:

	%define %$arg1	[esp+4]
	test	eax,eax
	if	nz
		mov	eax,%$arg1

    In this example the "if" mmacro enters into the "if" context, so %$arg1
    is not valid anymore inside "if". Of course it could be worked around
    by using explicitely %$$arg1 but this is ugly IMHO.

* Fixed memory leak in %undef. The origline wasn't freed before
    exiting on success.

* Fixed trap in preprocessor when line expanded to empty set of tokens.
    This happens, for example, in the following case:

	#define SOMETHING


All changes since NASM 0.98p3 have been produced by H. Peter Anvin <>.

* The documentation comment delimiter is \# not #.
* Allow EQU definitions to refer to external labels; reported by
  Pedro Gimeno.
* Re-enable support for RDOFF v1; reported by Pedro Gimeno.
* Updated License file per OK from Simon and Julian.


* Update documentation (although the instruction set reference will
  have to wait; I don't want to hold up the 0.98 release for it.)
* Verified that the NASM implementation of the PEXTRW and PMOVMSKB
  instructions is correct.  The encoding differs from what the Intel
  manuals document, but the Pentium III behaviour matches NASM, not
  the Intel manuals.
* Fix handling of implicit sizes in PSHUFW and PINSRW, reported by
  Stefan Hoffmeister.
* Resurrect the -s option, which was removed when changing the
  diagnostic output to stdout.


* Fix for "DB" when NASM is running on a bigendian machine.
* Invoke once for each output script, making
  legal for "make -j".
* Improve the Unix configure-based makefiles to make package
  creation easier.
* Included an RPM .spec file for building RPM (RedHat Package Manager)
  packages on Linux or Unix systems.
* Fix Makefile dependency problems.
* Change src/ to include sectioning information in info
  output; required for install-info to work.
* Updated the RDOFF distribution to version 2 from Jules; minor
  massaging to make it compile in my environment.
* Split doc files that can be built by anyone with a Perl interpreter off
  into a separate archive.
* "Dress rehearsal" release!


* Fixed opcodes with a third byte-sized immediate argument to not
  complain if given "byte" on the immediate.
* Allow %undef to remove single-line macros with arguments.  This
  matches the behaviour of #undef in the C preprocessor.
* Allow -d, -u, -i and -p to be specified as -D, -U, -I and -P for
  compatibility with most C compilers and preprocessors.  This allows
  Makefile options to be shared between cc and nasm, for example.
* Minor cleanups.
* Went through the list of Katmai instructions and hopefully fixed the
  (rather few) mistakes in it.
* (Hopefully) fixed a number of disassembler bugs related to ambiguous
  instructions (disambiguated by -p) and SSE instructions with REP.
* Fix for bug reported by Mark Junger: "call dword 0x12345678" should
  work and may add an OSP (affected CALL, JMP, Jcc).
* Fix for environments when "stderr" isn't a compile-time constant.


* Took officially over coordination of the 0.98 release; so drop
  the p3.x notation. Skipped p4 and p5 to avoid confusion with John
  Fine's J4 and J5 releases.
* Update the documentation; however, it still doesn't include
  documentation for the various new instructions.  I somehow wonder if
  it makes sense to have an instruction set reference in the assembler
  manual when Intel et al have PDF versions of their manuals online.
* Recognize "idt" or "centaur" for the -p option to ndisasm.
* Changed error messages back to stderr where they belong, but add an
  -E option to redirect them elsewhere (the DOS shell cannot redirect
* -M option to generate Makefile dependencies (based on code from Alex
* %undef preprocessor directive, and -u option, that undefines a
  single-line macro.
* OS/2 Makefile (Mkfiles/Makefile.os2) for Borland under OS/2; from
  Chuck Crayne.
* Various minor bugfixes (reported by):
  - Dangling %s in preproc.c (Martin Junker)
  on a trip and didn't bring the Katmai instruction reference, so I
  can't work on them right now.
* Updated the License file per agreement with Simon and Jules to
  include a GPL distribution clause.


* (Hopefully) fixed the canned Makefiles to include the outrdf2 and
  zoutieee modules.
* Renamed changes.asm to changed.asm.


* Fixed a bunch of instructions that were added in 0.98p3.5 which had
  memory operands, and the address-size prefix was missing from the
  instruction pattern.


* Merged in changes from John S. Fine's 0.98-J5 release.  John's based
  0.98-J5 on my 0.98p3.3 release; this merges the changes.
* Expanded the instructions flag field to a long so we can fit more
  flags; mark SSE (KNI) and AMD or Katmai-specific instructions as
* Fix the "PRIV" flag on a bunch of instructions, and create new
  "PROT" flag for protected-mode-only instructions (orthogonal to if
  the instruction is privileged!) and new "SMM" flag for SMM-only
* Added AMD-only SYSCALL and SYSRET instructions.
* Make SSE actually work, and add new Katmai MMX instructions.
* Added a -p (preferred vendor) option to ndisasm so that it can
  distinguish e.g. Cyrix opcodes also used in SSE.  For example:

	ndisasm -p cyrix aliased.bin
	00000000  670F514310        paddsiw mm0,[ebx+0x10]
	00000005  670F514320        paddsiw mm0,[ebx+0x20]
	ndisasm -p intel aliased.bin
	00000000  670F514310        sqrtps xmm0,[ebx+0x10]
	00000005  670F514320        sqrtps xmm0,[ebx+0x20]
* Added a bunch of Cyrix-specific instructions.


* Made at least an attempt to modify all the additional Makefiles (in
  the Mkfiles directory).  I can't test it, but this was the best I
  could do.
* DOS DJGPP+"Opus Make" Makefile from John S. Fine.
* changes.asm changes from John S. Fine.


* Patch from Conan Brink to allow nesting of %rep directives.
* If we're going to allow INT01 as an alias for INT1/ICEBP (one of
  Jules 0.98p3 changes), then we should allow INT03 as an alias for INT3
  as well.
* Updated changes.asm to include the latest changes.
* Tried to clean up the <CR>s that had snuck in from a DOS/Windows
  environment into my Unix environment, and try to make sure than
  DOS/Windows users get them back.
* We would silently generate broken tools if insns.dat wasn't sorted
  properly.  Change so that the order doesn't matter.
* Fix bug in (introduced by me) which would cause conditional
  instructions to have an extra "cc" in disassembly, e.g. "jnz"
  disassembled as "jccnz".


* Merged in John S. Fine's changes from his 0.98-J4 prerelease; see
* Changed previous "spotless" Makefile target (appropriate for distribution)
  to "distclean", and added "cleaner" target which is same as "clean"
  except deletes files generated by Perl scripts; "spotless" is union.
* Removed BASIC programs from distribution.  Get a Perl interpreter
  instead (see below.)
* Calling this "pre-release 3.2" rather than "p3-hpa2" because of
  John's contributions.
* Actually link in the IEEE output format (zoutieee.c); fix a bunch of
  compiler warnings in that file.  Note I don't know what IEEE output
  is supposed to look like, so these changes were made "blind".


* Merged with nasm-0.97.tar.gz to create a fully
  buildable version for Unix systems ( updates, etc.)
* Changed to create the instruction tables in nasm.h and
  names.c, so that a new instruction can be added by adding it *only*
  to insns.dat.
* Added the following new instructions: SYSENTER, SYSEXIT, FXSAVE,
  FXRSTOR, UD1, UD2 (the latter two are two opcodes that Intel
  guarantee will never be used; one of them is documented as UD2 in
  Intel documentation, the other one just as "Undefined Opcode" --
  calling it UD1 seemed to make sense.)
* MAX_SYMBOL was defined to be 9, but LOADALL286 and LOADALL386 are 10
  characters long.  Now MAX_SYMBOL is derived from insns.dat.
* A note on the BASIC programs included: forget them.  insns.bas is
  already out of date.  Get yourself a Perl interpreter for your
  platform of choice at:

0.98 pre-release 3

added response file support, improved command line handling, new layout
help screen

fixed limit checking bug, 'OUT byte nn, reg' bug, and a couple of rdoff
related bugs, updated Wishlist; 0.98 Prerelease 3.

0.98 pre-release 2

fixed bug in outcoff.c to do with truncating section names longer
than 8 characters, referencing beyond end of string; 0.98 pre-release 2

0.98 pre-released May 1999

Fixed a bug whereby STRUC didn't work at all in RDF.

Fixed a problem with group specification in PUBDEFs in OBJ.

Improved ease of adding new output formats. Contribution due to
Fox Cutter.

Fixed a bug in relocations in the `bin' format: was showing up when
a relocatable reference crossed an 8192-byte boundary in any output

Fixed a bug in local labels: local-label lookups were inconsistent
between passes one and two if an EQU occurred between the definition
of a global label and the subsequent use of a local label local to
that global.

Fixed a seg-fault in the preprocessor (again) which happened when
you use a blank line as the first line of a multi-line macro
definition and then defined a label on the same line as a call to
that macro.

Fixed a stale-pointer bug in the handling of the NASM environment
variable. Thanks to Thomas McWilliams.

ELF had a hard limit on the number of sections which caused
segfaults when transgressed. Fixed.

Added ability for ndisasm to read from stdin by using `-' as the

ndisasm wasn't outputting the TO keyword. Fixed.

Fixed error cascade on bogus expression in %if - an error in
evaluation was causing the entire %if to be discarded, thus creating
trouble later when the %else or %endif was encountered.

Forward reference tracking was instruction-granular not operand-
granular, which was causing 286-specific code to be generated
needlessly on code of the form `shr word [forwardref],1'. Thanks to
Jim Hague for sending a patch.

All messages now appear on stdout, as sending them to stderr serves
no useful purpose other than to make redirection difficult.

Fixed the problem with EQUs pointing to an external symbol - this
now generates an error message.

Allowed multiple size prefixes to an operand, of which only the first
is taken into account.

Incorporated John Fine's changes, including fixes of a large number
of preprocessor bugs, some small problems in OBJ, and a reworking of
label handling to define labels before their line is assembled, rather
than after.

Reformatted a lot of the source code to be more readable. Included
'coding.txt' as a guideline for how to format code for contributors.

Stopped nested %reps causing a panic - they now cause a slightly more
friendly error message instead.

Fixed floating point constant problems (patch by Pedro Gimeno)

Fixed the return value of insn_size() not being checked for -1, indicating
an error.

Incorporated 3D now instructions.

Fixed the 'mov eax, eax + ebx' bug.

Fixed the GLOBAL EQU bug in ELF. Released developers release 3.

Incorporated John Fine's command line parsing changes

Incorporated David Lindauer's OMF debug support

Made changes for LCC 4.0 support (__NASM_CDecl__, removed register size
specification warning when sizes agree).

Released NASM 0.98 Pre-release 1

0.97 released December 1997

This was entirely a bug-fix release to 0.96, which seems to have got
cursed. Silly me.

Fixed stupid mistake in OBJ which caused `MOV EAX,<constant>' to
fail. Caused by an error in the `MOV EAX,<segment>' support.

ndisasm hung at EOF when compiled with lcc on Linux because lcc on
Linux somehow breaks feof(). ndisasm now does not rely on feof().

A heading in the documentation was missing due to a markup error in
the indexing. Fixed.

Fixed failure to update all pointers on realloc() within extended-
operand code in parser.c. Was causing wrong behaviour and seg faults
on lines such as `dd 0.0,0.0,0.0,0.0,...'

Fixed a subtle preprocessor bug whereby invoking one multi-line
macro on the first line of the expansion of another, when the second
had been invoked with a label defined before it, didn't expand the
inner macro. 

Added internal.doc back in to the distribution archives - it was
missing in 0.96 *blush*

Fixed bug causing 0.96 to be unable to assemble its own test files,
specifically objtest.asm. *blush again*

Fixed seg-faults and bogus error messages caused by mismatching
%rep and %endrep within multi-line macro definitions.

Fixed a problem with buffer overrun in OBJ, which was causing
corruption at ends of long PUBDEF records.

Separated DOS archives into main-program and documentation to reduce
download size.

0.96 released November 1997

Fixed a bug whereby, if `nasm sourcefile' would cause a filename
collision warning and put output into `nasm.out', then `nasm
sourcefile -o outputfile' still gave the warning even though the
`-o' was honoured.

Fixed name pollution under Digital UNIX: one of its header files
defined R_SP, which broke the enum in nasm.h.

Fixed minor instruction table problems: FUCOM and FUCOMP didn't have
two-operand forms; NDISASM didn't recognise the longer register
forms of PUSH and POP (eg FF F3 for PUSH BX); TEST mem,imm32 was
flagged as undocumented; the 32-bit forms of CMOV had 16-bit operand
size prefixes; `AAD imm' and `AAM imm' are no longer flagged as
undocumented because the Intel Architecture reference documents

Fixed a problem with the local-label mechanism, whereby strange
types of symbol (EQUs, auto-defined OBJ segment base symbols)
interfered with the `previous global label' value and screwed up
local labels.

Fixed a bug whereby the stub preprocessor didn't communicate with
the listing file generator, so that the -a and -l options in
conjunction would produce a useless listing file.

Merged `os2' object file format back into `obj', after discovering
that `obj' _also_ shouldn't have a link pass separator in a module
containing a non-trivial MODEND. Flat segments are now declared
using the FLAT attribute. `os2' is no longer a valid object format
name: use `obj'.

Removed the fixed-size temporary storage in the evaluator. Very very
long expressions (like `mov ax,1+1+1+1+...' for two hundred 1s or
so) should now no longer crash NASM.

Fixed a bug involving segfaults on disassembly of MMX instructions,
by changing the meaning of one of the operand-type flags in nasm.h.
This may cause other apparently unrelated MMX problems; it needs to
be tested thoroughly.

Fixed some buffer overrun problems with large OBJ output files.
Thanks to DJ Delorie for the bug report and fix.

Made preprocess-only mode actually listen to the %line markers as it
prints them, so that it can report errors more sanely.

Re-designed the evaluator to keep more sensible track of expressions
involving forward references: can now cope with previously-nightmare
situations such as
   mov ax,foo | bar
   foo equ 1
   bar equ 2

Added the ALIGN and ALIGNB standard macros.

Added PIC support in ELF: use of WRT to obtain the four extra
relocation types needed.

Added the ability for output file formats to define their own
extensions to the GLOBAL, COMMON and EXTERN directives.

Implemented common-variable alignment, and global-symbol type and
size declarations, in ELF.

Implemented NEAR and FAR keywords for common variables, plus
far-common element size specification, in OBJ.

Added a feature whereby EXTERNs and COMMONs in OBJ can be given a
default WRT specification (either a segment or a group).

Transformed the Unix NASM archive into an auto-configuring package.

Added a sanity-check for people applying SEG to things which are
already segment bases: this previously went unnoticed by the SEG
processing and caused OBJ-driver panics later.

Added the ability, in OBJ format, to deal with `MOV EAX,<segment>'
type references: OBJ doesn't directly support dword-size segment
base fixups, but as long as the low two bytes of the constant term
are zero, a word-size fixup can be generated instead and it will

Added the ability to specify sections' alignment requirements in
Win32 object files and pure binary files.

Added preprocess-time expression evaluation: the %assign (and
%iassign) directive and the bare %if (and %elif) conditional. Added
relational operators to the evaluator, for use only in %if
constructs: the standard relationals = < > <= >= <> (and C-like
synonyms == and !=) plus low-precedence logical operators &&, ^^ and

Added a preprocessor repeat construct: %rep / %exitrep / %endrep.

Added the __FILE__ and __LINE__ standard macros.

Added a sanity check for number constants being greater than
0xFFFFFFFF. The warning can be disabled.

Added the %0 token whereby a variadic multi-line macro can tell how
many parameters it's been given in a specific invocation.

Added %rotate, allowing multi-line macro parameters to be cycled.

Added the `*' option for the maximum parameter count on multi-line
macros, allowing them to take arbitrarily many parameters.

Added the ability for the user-level forms of EXTERN, GLOBAL and
COMMON to take more than one argument.

Added the IMPORT and EXPORT directives in OBJ format, to deal with
Windows DLLs.

Added some more preprocessor %if constructs: %ifidn / %ifidni (exact
textual identity), and %ifid / %ifnum / %ifstr (token type testing).

Added the ability to distinguish SHL AX,1 (the 8086 version) from
SHL AX,BYTE 1 (the 286-and-upwards version whose constant happens to
be 1).

Added NetBSD/FreeBSD/OpenBSD's variant of a.out format, complete
with PIC shared library features.

Changed NASM's idiosyncratic handling of FCLEX, FDISI, FENI, FINIT,
FSAVE, FSTCW, FSTENV, and FSTSW to bring it into line with the
otherwise accepted standard. The previous behaviour, though it was a
deliberate feature, was a deliberate feature based on a
misunderstanding. Apologies for the inconvenience.

Improved the flexibility of ABSOLUTE: you can now give it an
expression rather than being restricted to a constant, and it can
take relocatable arguments as well.

Added the ability for a variable to be declared as EXTERN multiple
times, and the subsequent definitions are just ignored.

We now allow instruction prefixes (CS, DS, LOCK, REPZ etc) to be
alone on a line (without a following instruction).

Improved sanity checks on whether the arguments to EXTERN, GLOBAL
and COMMON are valid identifiers.

Added misc/exebin.mac to allow direct generation of .EXE files by
hacking up an EXE header using DB and DW; also added test/binexe.asm
to demonstrate the use of this. Thanks to Yann Guidon for
contributing the EXE header code.

ndisasm forgot to check whether the input file had been successfully
opened. Now it does. Doh!

Added the Cyrix extensions to the MMX instruction set.

Added a hinting mechanism to allow [EAX+EBX] and [EBX+EAX] to be
assembled differently. This is important since [ESI+EBP] and
[EBP+ESI] have different default base segment registers.

Added support for the PharLap OMF extension for 4096-byte segment

0.95 released July 1997

Fixed yet another ELF bug. This one manifested if the user relied on
the default segment, and attempted to define global symbols without
first explicitly declaring the target segment.

Added makefiles (for NASM and the RDF tools) to build Win32 console
apps under Symantec C++. Donated by Mark Junker.

Added `macros.bas' and `insns.bas', QBasic versions of the Perl
scripts that convert `standard.mac' to `macros.c' and convert
`insns.dat' to `insnsa.c' and `insnsd.c'. Also thanks to Mark

Changed the diassembled forms of the conditional instructions so
that JB is now emitted as JC, and other similar changes. Suggested
list by Ulrich Doewich.

Added `@' to the list of valid characters to begin an identifier

Documentary changes, notably the addition of the `Common Problems'
section in nasm.doc.

Fixed a bug relating to 32-bit PC-relative fixups in OBJ.

Fixed a bug in perm_copy() in labels.c which was causing exceptions
in cleanup_labels() on some systems.

Positivity sanity check in TIMES argument changed from a warning to
an error following a further complaint.

Changed the acceptable limits on byte and word operands to allow
things like `~10111001b' to work.

Fixed a major problem in the preprocessor which caused seg-faults if
macro definitions contained blank lines or comment-only lines.

Fixed inadequate error checking on the commas separating the
arguments to `db', `dw' etc.

Fixed a crippling bug in the handling of macros with operand counts
defined with a `+' modifier.

Fixed a bug whereby object file formats which stored the input file
name in the output file (such as OBJ and COFF) weren't doing so
correctly when the output file name was specified on the command

Removed [INC] and [INCLUDE] support for good, since they were
obsolete anyway.

Fixed a bug in OBJ which caused all fixups to be output in 16-bit
(old-format) FIXUPP records, rather than putting the 32-bit ones in
FIXUPP32 (new-format) records.

Added, tentatively, OS/2 object file support (as a minor variant on

Updates to Fox Cutter's Borland C makefile, Makefile.bc2.

Removed a spurious second fclose() on the output file.

Added the `-s' command line option to redirect all messages which
would go to stderr (errors, help text) to stdout instead.

Added the `-w' command line option to selectively suppress some
classes of assembly warning messages.

Added the `-p' pre-include and `-d' pre-define command-line options.

Added an include file search path: the `-i' command line option.

Fixed a silly little preprocessor bug whereby starting a line with a
`%!' environment-variable reference caused an `unknown directive'

Added the long-awaited listing file support: the `-l' command line

Fixed a problem with OBJ format whereby, in the absence of any
explicit segment definition, non-global symbols declared in the
implicit default segment generated spurious EXTDEF records in the

Added the NASM environment variable.

From this version forward, Win32 console-mode binaries will be
included in the DOS distribution in addition to the 16-bit binaries.
Added for this purpose.

Added `return 0;' to test/objlink.c to prevent compiler warnings.

Added the __NASM_MAJOR__ and __NASM_MINOR__ standard defines.

Added an alternative memory-reference syntax in which prefixing an
operand with `&' is equivalent to enclosing it in square brackets,
at the request of Fox Cutter.

Errors in pass two now cause the program to return a non-zero error
code, which they didn't before.

Fixed the single-line macro cycle detection, which didn't work at
all on macros with no parameters (caused an infinite loop). Also
changed the behaviour of single-line macro cycle detection to work
like cpp, so that macros like `extrn' as given in the documentation
can be implemented.

Fixed the implementation of WRT, which was too restrictive in that
you couldn't do `mov ax,[di+abc wrt dgroup]' because (di+abc) wasn't
a relocatable reference.

0.94 released April 1997

Major item: added the macro processor.

Added undocumented instructions SMI, IBTS, XBTS and LOADALL286. Also
reorganised CMPXCHG instruction into early-486 and Pentium forms.
Thanks to Thobias Jones for the information.

Fixed two more stupid bugs in ELF, which were causing `ld' to
continue to seg-fault in a lot of non-trivial cases.

Fixed a seg-fault in the label manager.

Stopped FBLD and FBSTP from _requiring_ the TWORD keyword, which is
the only option for BCD loads/stores in any case.

Ensured FLDCW, FSTCW and FSTSW can cope with the WORD keyword, if
anyone bothers to provide it. Previously they complained unless no
keyword at all was present.

Some forms of FDIV/FDIVR and FSUB/FSUBR were still inverted: a
vestige of a bug that I thought had been fixed in 0.92. This was
fixed, hopefully for good this time...

Another minor phase error (insofar as a phase error can _ever_ be
minor) fixed, this one occurring in code of the form
   rol ax,forward_reference
   forward_reference equ 1

The number supplied to TIMES is now sanity-checked for positivity,
and also may be greater than 64K (which previously didn't work on
16-bit systems).

Added Watcom C makefiles, and misc/pmw.bat, donated by Dominik Behr.

Added the INCBIN pseudo-opcode.

Due to the advent of the preprocessor, the [INCLUDE] and [INC]
directives have become obsolete. They are still supported in this
version, with a warning, but won't be in the next.

Fixed a bug in OBJ format, which caused incorrect object records to
be output when absolute labels were made global.

Updates to RDOFF subdirectory, and changes to outrdf.c.

0.93 released January 1997

This release went out in a great hurry after semi-crippling bugs
were found in 0.92.

Really _did_ fix the stack overflows this time. *blush*

Had problems with EA instruction sizes changing between passes, when
an offset contained a forward reference and so 4 bytes were
allocated for the offset in pass one; by pass two the symbol had
been defined and happened to be a small absolute value, so only 1
byte got allocated, causing instruction size mismatch between passes
and hence incorrect address calculations. Fixed.

Stupid bug in the revised ELF section generation fixed (associated
string-table section for .symtab was hard-coded as 7, even when this
didn't fit with the real section table). Was causing `ld' to
seg-fault under Linux.

Included a new Borland C makefile, Makefile.bc2, donated by Fox
Cutter <>.

0.92 released January 1997

The FDIVP/FDIVRP and FSUBP/FSUBRP pairs had been inverted: this was
fixed. This also affected the LCC driver.

Fixed a bug regarding 32-bit effective addresses of the form

Documentary changes, notably documentation of the fact that Borland
Win32 compilers use `obj' rather than `win32' object format.

Fixed the COMENT record in OBJ files, which was formatted

Fixed a bug causing segfaults in large RDF files.

OBJ format now strips initial periods from segment and group
definitions, in order to avoid complications with the local label

Fixed a bug in disassembling far calls and jumps in NDISASM.

Added support for user-defined sections in COFF and ELF files.

Compiled the DOS binaries with a sensible amount of stack, to
prevent stack overflows on any arithmetic expression containing

Fixed a bug in handling of files that do not terminate in a newline.

0.91 released November 1996

Loads of bug fixes.
Support for RDF added.
Support for DBG debugging format added.
Support for 32-bit extensions to Microsoft OBJ format added.
Revised for Borland C: some variable names changed, makefile added.
LCC support revised to actually work.
JMP/CALL NEAR/FAR notation added.
`a16', `o16', `a32' and `o32' prefixes added.
Range checking on short jumps implemented.
MMX instruction support added.
Negative floating point constant support added.
Memory handling improved to bypass 64K barrier under DOS.
$ prefix to force treatment of reserved words as identifiers added.
Default-size mechanism for object formats added.
Compile-time configurability added.
`#', `@', `~' and `?' are now valid characters in labels.
`-e' and `-k' options in NDISASM added.

0.90 released October 1996

First release version. First support for object file output. Other
changes from previous version (0.3x) too numerous to document.