disasm: collapse all the segment register push/pop bytecodes

As far as the disassembler is concerned, the segment register push/pop
bytecodes can be collapsed to a simple expression; the remaining
differences are handled by the filter expressions in insns.pl.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/disasm.c b/disasm.c
index e3b0224..4efcdc8 100644 (file)
--- a/disasm.c
+++ b/disasm.c
@@ -830,65 +830,8 @@ static int matches(const struct itemplate *t, uint8_t *data,
        case 0340:
            return false;
 
-       case 0344:
-            switch (*data++) {
-            case 0x06:
-                ins->oprs[0].basereg = 0;
-                break;
-            case 0x0E:
-                ins->oprs[0].basereg = 1;
-                break;
-            case 0x16:
-                ins->oprs[0].basereg = 2;
-                break;
-            case 0x1E:
-                ins->oprs[0].basereg = 3;
-                break;
-            default:
-                return false;
-            }
-           break;
-
-       case 0345:
-            switch (*data++) {
-            case 0x07:
-                ins->oprs[0].basereg = 0;
-                break;
-            case 0x17:
-                ins->oprs[0].basereg = 2;
-                break;
-            case 0x1F:
-                ins->oprs[0].basereg = 3;
-                break;
-            default:
-                return false;
-            }
-           break;
-
-       case 0346:
-            switch (*data++) {
-            case 0xA0:
-                ins->oprs[0].basereg = 4;
-                break;
-            case 0xA8:
-                ins->oprs[0].basereg = 5;
-                break;
-            default:
-                return false;
-            }
-           break;
-
-       case 0347:
-            switch (*data++) {
-            case 0xA1:
-                ins->oprs[0].basereg = 4;
-                break;
-            case 0xA9:
-                ins->oprs[0].basereg = 5;
-                break;
-            default:
-                return false;
-           }
+       case4(0344):
+           ins->oprs[0].basereg = (*data++ >> 3) & 7;
            break;
 
        case 0360: