changes

一个汇编语言编译器源码

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
work.

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
alignment.

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.

0.98 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
section.

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
filename.

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

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

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.

See the file "MODIFIED" for changes after 0.98p3.