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
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
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