x86: Add {rex} pseudo prefix

Add {rex} pseudo prefix to generate a REX byte for integer and legacy
vector instructions if possible.  Note that this differs from the rex
prefix which generates REX prefix unconditionally.

gas/

	* config/tc-i386.c (_i386_insn): Add rex_encoding.
	(md_assemble): When i.rex_encoding is true, generate a REX byte
	if possible.
	(parse_insn): Set i.rex_encoding for {rex}.
	* doc/c-i386.texi: Document {rex}.
	* testsuite/gas/i386/x86-64-pseudos.s: Add {rex} tests.
	* testsuite/gas/i386/x86-64-pseudos.d: Updated.

opcodes/

	* i386-opc.tbl: Add {rex},
	* i386-tbl.h: Regenerated.

diff --git a/gas/ChangeLog b/gas/ChangeLog
index ce7e258..20ea246 100644 (file)
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,13 @@
+2018-02-22  H.J. Lu  <hongjiu.lu@intel.com>
+
+       * config/tc-i386.c (_i386_insn): Add rex_encoding.
+       (md_assemble): When i.rex_encoding is true, generate a REX byte
+       if possible.
+       (parse_insn): Set i.rex_encoding for {rex}.
+       * doc/c-i386.texi: Document {rex}.
+       * testsuite/gas/i386/x86-64-pseudos.s: Add {rex} tests.
+       * testsuite/gas/i386/x86-64-pseudos.d: Updated.
+
 2018-02-22  A. Wilcox  <awilfox@adelielinux.org>
 
        PR 22014

diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index c67ea1f..dff42bd 100644 (file)
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -369,6 +369,9 @@ struct _i386_insn
        disp_encoding_32bit
       } disp_encoding;
 
+    /* Prefer the REX byte in encoding.  */
+    bfd_boolean rex_encoding;
+
     /* How to encode vector instructions.  */
     enum
       {
@@ -3992,6 +3995,26 @@ md_assemble (char *line)
        }
     }
 
+  if (i.rex == 0 && i.rex_encoding)
+    {
+      /* Check if we can add a REX_OPCODE byte.  Look for 8 bit operand
+         that uses legacy register.  If it is "hi" register, don't add
+        the REX_OPCODE byte.  */
+      int x;
+      for (x = 0; x < 2; x++)
+       if (i.types[x].bitfield.reg
+           && i.types[x].bitfield.byte
+           && (i.op[x].regs->reg_flags & RegRex64) == 0
+           && i.op[x].regs->reg_num > 3)
+         {
+           i.rex_encoding = FALSE;
+           break;
+         }
+
+      if (i.rex_encoding)
+       i.rex = REX_OPCODE;
+    }
+
   if (i.rex != 0)
     add_prefix (REX_OPCODE | i.rex);
 
@@ -4104,6 +4127,10 @@ parse_insn (char *line, char *mnemonic)
                  /* {evex} */
                  i.vec_encoding = vex_encoding_evex;
                  break;
+               case 0x7:
+                 /* {rex} */
+                 i.rex_encoding = TRUE;
+                 break;
                default:
                  abort ();
                }

diff --git a/gas/doc/c-i386.texi b/gas/doc/c-i386.texi
index e669c5f..6b2def0 100644 (file)
--- a/gas/doc/c-i386.texi
+++ b/gas/doc/c-i386.texi
@@ -642,6 +642,11 @@ Different encoding options can be specified via pseudo prefixes:
 
 @item
 @samp{@{evex@}} --  encode with EVEX prefix.
+
+@item
+@samp{@{rex@}} -- prefer REX prefix for integer and legacy vector
+instructions (x86-64 only).  Note that this differs from the @samp{rex}
+prefix which generates REX prefix unconditionally.
 @end itemize
 
 @cindex conversion instructions, i386

diff --git a/gas/testsuite/gas/i386/x86-64-pseudos.d b/gas/testsuite/gas/i386/x86-64-pseudos.d
index c63a0a1..de8c8eb 100644 (file)
--- a/gas/testsuite/gas/i386/x86-64-pseudos.d
+++ b/gas/testsuite/gas/i386/x86-64-pseudos.d
@@ -35,6 +35,19 @@ Disassembly of section .text:
  +[a-f0-9]+:   0f 28 90 80 00 00 00    movaps 0x80\(%rax\),%xmm2
  +[a-f0-9]+:   0f 28 90 80 00 00 00    movaps 0x80\(%rax\),%xmm2
  +[a-f0-9]+:   0f 28 90 80 00 00 00    movaps 0x80\(%rax\),%xmm2
+ +[a-f0-9]+:   88 c4                   mov    %al,%ah
+ +[a-f0-9]+:   40 89 c3                rex mov %eax,%ebx
+ +[a-f0-9]+:   41 89 c6                mov    %eax,%r14d
+ +[a-f0-9]+:   41 89 00                mov    %eax,\(%r8\)
+ +[a-f0-9]+:   40 0f 28 d7             rex movaps %xmm7,%xmm2
+ +[a-f0-9]+:   44 0f 28 e7             movaps %xmm7,%xmm12
+ +[a-f0-9]+:   40 0f 28 11             rex movaps \(%rcx\),%xmm2
+ +[a-f0-9]+:   41 0f 28 10             movaps \(%r8\),%xmm2
+ +[a-f0-9]+:   40 0f 38 01 01          rex phaddw \(%rcx\),%mm0
+ +[a-f0-9]+:   41 0f 38 01 00          phaddw \(%r8\),%mm0
+ +[a-f0-9]+:   c5 f8 28 d7             vmovaps %xmm7,%xmm2
+ +[a-f0-9]+:   62 b1 7c 08 28 d1       vmovaps %xmm17,%xmm2
+ +[a-f0-9]+:   c4 e3 7b f0 d8 07       rorx   \$0x7,%eax,%ebx
  +[a-f0-9]+:   c4 e1 78 28 d7          vmovaps %xmm7,%xmm2
  +[a-f0-9]+:   c4 e1 78 28 d7          vmovaps %xmm7,%xmm2
  +[a-f0-9]+:   c4 e1 78 29 fa          vmovaps %xmm7,%xmm2
@@ -63,4 +76,17 @@ Disassembly of section .text:
  +[a-f0-9]+:   0f 28 90 80 00 00 00    movaps 0x80\(%rax\),%xmm2
  +[a-f0-9]+:   0f 28 90 80 00 00 00    movaps 0x80\(%rax\),%xmm2
  +[a-f0-9]+:   0f 28 90 80 00 00 00    movaps 0x80\(%rax\),%xmm2
+ +[a-f0-9]+:   88 c4                   mov    %al,%ah
+ +[a-f0-9]+:   40 89 c3                rex mov %eax,%ebx
+ +[a-f0-9]+:   41 89 c6                mov    %eax,%r14d
+ +[a-f0-9]+:   41 89 00                mov    %eax,\(%r8\)
+ +[a-f0-9]+:   40 0f 28 d7             rex movaps %xmm7,%xmm2
+ +[a-f0-9]+:   44 0f 28 e7             movaps %xmm7,%xmm12
+ +[a-f0-9]+:   40 0f 28 11             rex movaps \(%rcx\),%xmm2
+ +[a-f0-9]+:   41 0f 28 10             movaps \(%r8\),%xmm2
+ +[a-f0-9]+:   40 0f 38 01 01          rex phaddw \(%rcx\),%mm0
+ +[a-f0-9]+:   41 0f 38 01 00          phaddw \(%r8\),%mm0
+ +[a-f0-9]+:   c5 f8 28 d7             vmovaps %xmm7,%xmm2
+ +[a-f0-9]+:   62 b1 7c 08 28 d1       vmovaps %xmm17,%xmm2
+ +[a-f0-9]+:   c4 e3 7b f0 d8 07       rorx   \$0x7,%eax,%ebx
 #pass

diff --git a/gas/testsuite/gas/i386/x86-64-pseudos.s b/gas/testsuite/gas/i386/x86-64-pseudos.s
index c0ee8dc..c213769 100644 (file)
--- a/gas/testsuite/gas/i386/x86-64-pseudos.s
+++ b/gas/testsuite/gas/i386/x86-64-pseudos.s
@@ -30,6 +30,19 @@ _start:
        movaps 128(%rax),%xmm2
        {disp8} movaps 128(%rax),%xmm2
        {disp32} movaps 128(%rax),%xmm2
+       {rex} mov %al,%ah
+       {rex} movl %eax,%ebx
+       {rex} movl %eax,%r14d
+       {rex} movl %eax,(%r8)
+       {rex} movaps %xmm7,%xmm2
+       {rex} movaps %xmm7,%xmm12
+       {rex} movaps (%rcx),%xmm2
+       {rex} movaps (%r8),%xmm2
+       {rex} phaddw (%rcx),%mm0
+       {rex} phaddw (%r8),%mm0
+       {rex} vmovaps %xmm7,%xmm2
+       {rex} vmovaps %xmm17,%xmm2
+       {rex} rorx $7,%eax,%ebx
 
        .intel_syntax noprefix
        {vex3} vmovaps xmm2,xmm7
@@ -60,3 +73,16 @@ _start:
        movaps xmm2,XMMWORD PTR [rax+128]
        {disp8} movaps xmm2,XMMWORD PTR [rax+128]
        {disp32} movaps xmm2,XMMWORD PTR [rax+128]
+       {rex} mov ah,al
+       {rex} mov ebx,eax
+       {rex} mov r14d,eax
+       {rex} mov DWORD PTR [r8],eax
+       {rex} movaps xmm2,xmm7
+       {rex} movaps xmm12,xmm7
+       {rex} movaps xmm2,XMMWORD PTR [rcx]
+       {rex} movaps xmm2,XMMWORD PTR [r8]
+       {rex} phaddw mm0,QWORD PTR [rcx]
+       {rex} phaddw mm0,QWORD PTR [r8]
+       {rex} vmovaps xmm2,xmm7
+       {rex} vmovaps xmm2,xmm17
+       {rex} rorx ebx,eax,0x7

diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 58d352d..b4b4cbb 100644 (file)
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,8 @@
+2018-02-22  H.J. Lu  <hongjiu.lu@intel.com>
+
+       * i386-opc.tbl: Add {rex},
+       * i386-tbl.h: Regenerated.
+
 2018-02-20  Maciej W. Rozycki  <macro@mips.com>
 
        * mips16-opc.c (decode_mips16_operand) <'M'>: Remove case.

diff --git a/opcodes/i386-opc.tbl b/opcodes/i386-opc.tbl
index 481e99f..4503505 100644 (file)
--- a/opcodes/i386-opc.tbl
+++ b/opcodes/i386-opc.tbl
@@ -829,6 +829,7 @@ rex.wrxb, 0, 0x4f, None, 1, Cpu64, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ld
 {vex2}, 0, 0x4, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, { 0 }
 {vex3}, 0, 0x5, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, { 0 }
 {evex}, 0, 0x6, None, 0, 0, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, { 0 }
+{rex}, 0, 0x7, None, 0, Cpu64, No_bSuf|No_wSuf|No_lSuf|No_sSuf|No_qSuf|No_ldSuf|IsPrefix, { 0 }
 
 // 486 extensions.
 

diff --git a/opcodes/i386-tbl.h b/opcodes/i386-tbl.h
index f0b9241..edb32fd 100644 (file)
--- a/opcodes/i386-tbl.h
+++ b/opcodes/i386-tbl.h
@@ -9293,6 +9293,20 @@ const insn_template i386_optab[] =
     { { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
          0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
          0, 0, 0 } } } },
+  { "{rex}", 0, 0x7, None, 0,
+    { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 1, 0, 0 } },
+    { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,
+      1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0,
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+      0, 0, 0, 0, 0 },
+    { { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+         0, 0, 0 } } } },
   { "bswap", 1, 0xfc8, None, 2,
     { { 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,