X86: Add pseudo prefixes to control encoding

Many x86 instructions have more than one encodings.  Assembler picks
the default one, usually the shortest one.  Although the ".s", ".d8"
and ".d32" suffixes can be used to swap register operands or specify
displacement size, they aren't very flexible.  This patch adds pseudo
prefixes, {xxx}, to control instruction encoding.  The available
pseudo prefixes are {disp8}, {disp32}, {load}, {store}, {vex2}, {vex3}
and {evex}.  Pseudo prefixes are preferred over the ".s", ".d8" and
".d32" suffixes, which are deprecated.

gas/

	* config/tc-i386.c (_i386_insn): Add dir_encoding and
	vec_encoding.  Remove swap_operand and need_vrex.
	(extra_symbol_chars): Add '}'.
	(md_begin): Mark '}' with LEX_BEGIN_NAME.  Allow '}' in
	mnemonic.
	(build_vex_prefix): Don't use 2-byte VEX encoding with
	{vex3}.  Check dir_encoding and load.
	(parse_insn): Check pseudo prefixes.  Set dir_encoding.
	(VEX_check_operands): Likewise.
	(match_template): Check dir_encoding and load.
	(parse_real_register): Set vec_encoding instead of need_vrex.
	(parse_register): Likewise.
	* doc/c-i386.texi: Document {disp8}, {disp32}, {load}, {store},
	{vex2}, {vex3} and {evex}.  Remove ".s", ".d8" and ".d32"
	* testsuite/gas/i386/i386.exp: Run pseudos and x86-64-pseudos.
	* testsuite/gas/i386/pseudos.d: New file.
	* testsuite/gas/i386/pseudos.s: Likewise.
	* testsuite/gas/i386/x86-64-pseudos.d: Likewise.
	* testsuite/gas/i386/x86-64-pseudos.s: Likewise.

opcodes/

	* i386-gen.c (opcode_modifiers): Replace S with Load.
	* i386-opc.h (S): Removed.
	(Load): New.
	(i386_opcode_modifier): Replace s with load.
	* i386-opc.tbl: Add {disp8}, {disp32}, {swap}, {vex2}, {vex3}
	and {evex}.  Replace S with Load.
	* i386-tbl.h: Regenerated.

1 files changed, 24 insertions, 4 deletions

diff --git a/gas/doc/c-i386.texi b/gas/doc/c-i386.texi
index 0733587..32f4289 100644
--- a/gas/doc/c-i386.texi
+++ b/gas/doc/c-i386.texi
@@ -598,10 +598,30 @@ quadruple word).
 @cindex encoding options, i386
 @cindex encoding options, x86-64
 
-Different encoding options can be specified via optional mnemonic
-suffix.  @samp{.s} suffix swaps 2 register operands in encoding when
-moving from one register to another.  @samp{.d8} or @samp{.d32} suffix
-prefers 8bit or 32bit displacement in encoding.
+Different encoding options can be specified via pseudo prefixes:
+
+@itemize @bullet
+@item
+@samp{@{disp8@}} -- prefer 8-bit displacement.
+
+@item
+@samp{@{disp32@}} -- prefer 32-bit displacement.
+
+@item
+@samp{@{load@}} -- prefer load-form instruction.
+
+@item
+@samp{@{store@}} -- prefer store-form instruction.
+
+@item
+@samp{@{vex2@}} -- prefer 2-byte VEX prefix for VEX instruction.
+
+@item
+@samp{@{vex3@}} -- prefer 3-byte VEX prefix for VEX instruction.
+
+@item
+@samp{@{evex@}} --  encode with EVEX prefix.
+@end itemize
 
 @cindex conversion instructions, i386
 @cindex i386 conversion instructions