[binutils-gdb] x86/APX: correct disassembly for EVEX.B4

[Jan Beulich]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=6170a088a60e159f2ab8ac1ae1edab7d04e079ec

commit 6170a088a60e159f2ab8ac1ae1edab7d04e079ec
Author: Jan Beulich <jbeulich@suse.com>
Date:   Wed Sep 11 13:52:42 2024 +0200

    x86/APX: correct disassembly for EVEX.B4
    
    EVEX.B4 is used only for GPR (or addressing of memory) operands. SIMD
    registers encoded via ModR/M.rm (when ModR/M.mod == 3) have their top
    bit in EVEX.X3. Supposedly (doc version 004) EVEX.B4 is ignored when
    unused, hence also don't flag such encodings as invalid.

Diff:
---
 opcodes/i386-dis.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/opcodes/i386-dis.c b/opcodes/i386-dis.c
index 26d667a3b0e..e2c7b1b4ac7 100644
--- a/opcodes/i386-dis.c
+++ b/opcodes/i386-dis.c
@@ -13012,14 +13012,15 @@ OP_EX (instr_info *ins, int bytemode, int sizeflag)
   USED_REX (REX_B);
   if (ins->rex & REX_B)
     reg += 8;
-  if (ins->rex2 & REX_B)
-    reg += 16;
   if (ins->vex.evex)
     {
       USED_REX (REX_X);
       if ((ins->rex & REX_X))
 	reg += 16;
+      ins->rex2_used &= ~REX_B;
     }
+  else if (ins->rex2 & REX_B)
+    reg += 16;
 
   if ((sizeflag & SUFFIX_ALWAYS)
       && (bytemode == x_swap_mode