[PATCH 09/19] x86: merge/move logic determining the EVEX disp8 shift

[Jan Beulich]

Fold redundant case blocks and move the extra adjustments logic into
the single case block that actually needs it - there's no need to go
through the extra logic for all the other cases. Also utilize there that
vex.b cannot be set at this point, due to earlier logic. Reduce the
comment there, which was partly stale anyway.

opcodes/
2020-07-XX  Jan Beulich  <jbeulich@suse.com>

	* i386-dis.c (OP_E_memory): Move xmm_mw_mode, xmm_mb_mode,
	dqd_mode, xmm_md_mode, d_mode, d_swap_mode, and
	d_scalar_swap_mode case handling. Move shift adjsutment into
	the case its applicable to.

--- a/opcodes/i386-dis.c
+++ b/opcodes/i386-dis.c
@@ -14517,15 +14517,22 @@ OP_E_memory (int bytemode, int sizeflag)
 	{
 	case dqw_mode:
 	case dw_mode:
+	case xmm_mw_mode:
 	  shift = 1;
 	  break;
 	case dqb_mode:
 	case db_mode:
+	case xmm_mb_mode:
 	  shift = 0;
 	  break;
 	case dq_mode:
 	  if (address_mode != mode_64bit)
 	    {
+	case dqd_mode:
+	case xmm_md_mode:
+	case d_mode:
+	case d_swap_mode:
+	case d_scalar_swap_mode:
 	      shift = 2;
 	      break;
 	    }
@@ -14566,6 +14573,15 @@ OP_E_memory (int bytemode, int sizeflag)
 	    default:
 	      abort ();
 	    }
+	  /* Make necessary corrections to shift for modes that need it.  */
+	  if (bytemode == xmmq_mode
+	      || bytemode == evex_half_bcst_xmmq_mode
+	      || (bytemode == ymmq_mode && vex.length == 128))
+	    shift -= 1;
+	  else if (bytemode == xmmqd_mode)
+	    shift -= 2;
+	  else if (bytemode == xmmdw_mode)
+	    shift -= 3;
 	  break;
 	case ymm_mode:
 	  shift = 5;
@@ -14579,41 +14595,12 @@ OP_E_memory (int bytemode, int sizeflag)
 	case q_scalar_swap_mode:
 	  shift = 3;
 	  break;
-	case dqd_mode:
-	case xmm_md_mode:
-	case d_mode:
-	case d_swap_mode:
-	case d_scalar_swap_mode:
-	  shift = 2;
-	  break;
 	case bw_unit_mode:
 	  shift = vex.w ? 1 : 0;
 	  break;
-	case xmm_mw_mode:
-	  shift = 1;
-	  break;
-	case xmm_mb_mode:
-	  shift = 0;
-	  break;
 	default:
 	  abort ();
 	}
-      /* Make necessary corrections to shift for modes that need it.
-	 For these modes we currently have shift 4, 5 or 6 depending on
-	 vex.length (it corresponds to xmmword, ymmword or zmmword
-	 operand).  We might want to make it 3, 4 or 5 (e.g. for
-	 xmmq_mode).  In case of broadcast enabled the corrections
-	 aren't needed, as element size is always 32 or 64 bits.  */
-      if (!vex.b
-	  && (bytemode == xmmq_mode
-	      || bytemode == evex_half_bcst_xmmq_mode))
-	shift -= 1;
-      else if (bytemode == xmmqd_mode)
-	shift -= 2;
-      else if (bytemode == xmmdw_mode)
-	shift -= 3;
-      else if (bytemode == ymmq_mode && vex.length == 128)
-	shift -= 1;
     }
   else
     shift = 0;