Contributed by: Samuel Thibault <samuel.thibault@ens-lyon.org>
It is built on top of the NASM parser and preproc, with the following
notable extensions for TASM syntax:
- case insensitive symbols and filenames,
- support for segment and size of labels, which permits to avoid giving
them on each memory dereference,
- support for data reservation (i.e. e.g. "var dd ?"),
- support for multiples (i.e. e.g. "var dd 1 dup 10"),
- little endian string integer constants,
- additional expression operators: shl, shr, and, or, low, high,
- additional offset keyword,
- additional fword and df,
- support for doubled quotes within quotes,
- support for array-like and structure-like notations: t[eax] and
[var].field,
- support for tasm directives: macro, rept, irp, locals, proc, struc,
segment, assume.
Notes:
- Almost all extensions are only effective when tasm_compatible_mode is
set, so we should have very reduced possible breakage.
- Because the "and" keyword can be an expression operator and an
instruction name, the data pseudo-instructions explicitly switch the
lexer state to INSTRUCTION state to fix the ambiguity.
- In gen_x86_insn.py, several instructions (namely lds and lea) now take
relaxed memory sizes. The reason is that in the case of tasm, the size
of the actual pointed data is passed up to there, and thus any type of
data should be accepted.
With all of this, loadlin can be compiled by yasm with quite reduced
modifications.
A new TASM-like frontend is also included.
svn path=/trunk/yasm/; revision=2130
Add proper declspec dllimport/dllexport to all libyasm functions.
Use macros to make these do nothing on non-cmake and Unix builds.
svn path=/trunk/yasm/; revision=2101
Formerly:
foo equ 1:2
jmp foo
would result in a far jump. Now, an explicit "far" is required:
jmp far foo
to generate a far jump.
In addition, the direct use of seg:off in immediates and effective
addresses will result in an error; the use of EQU'ed seg:off values
is still legal (and will still result in just the offset). This
behavior is more sane and also matches NASM behavior.
Thus:
foo equ 1:2
mov ax, foo ; okay, just 2
mov ax, [foo] ; okay, just 2
mov ax, 1:2 ; illegal
mov ax, [1:2] ; illegal
svn path=/trunk/yasm/; revision=2028
This adds a "default" directive that takes either "rel" or "abs". This
sets whether the default mode for simple displacements is RIP-relative (rel)
or not (abs). The default without a directive is "abs".
Also added is corresponding "rel" and "abs" effective address modifiers
to override whatever default is set:
[rel label] is RIP-relative
[abs label] is not.
In default rel mode, [label] defaults to the former, in default abs mode,
the latter. Also, segment overrides (note difference from NASM below) are
abs regardless of mode, unless explicitly overridden with rel:
[fs:label] is always abs
[rel fs:label] is always rel
However, we have a number of differences from NASM in this handling due to
what I feel to be yasm's more sane handling of [dword ...] and [qword ...].
In yasm, these set the displacement size, rather than the address size; the
latter is set using a a32/a64 prefix. I feel this is more sane as in 64-bit
mode the two can be different in the MovOffs (A0/A1 mov *ax) case.
Also, yasm disables default-rel mode if any segment register is used, not
just FS or GS as NASM currently does.
See modules/arch/x86/tests/riprel1.asm and
modules/arch/x86/tests/riprel2.asm for examples, as well as my recent
posting to the nasm-devel mailing list on SF.
svn path=/trunk/yasm/; revision=1963
customize on the arch side of things. Instead of passing around an
arch_data[4] for instructions, now the arch can extend the structure itself
to add additional information in any format it likes.
svn path=/trunk/yasm/; revision=1889
Peter Johnson