Changeset 42050 in vbox for trunk/src/VBox/Disassembler

Timestamp:

Jul 9, 2012 12:41:24 PM (12 years ago)

Author:

vboxsync

Message:

DisasmFormatYasm.cpp: Fixed formatting of PUSH Ib with a operand size override. Extended DISFormatYasmIsOddEncoding a little bit more.

File:

• trunk/src/VBox/Disassembler/DisasmFormatYasm.cpp (modified) (8 diffs)

trunk/src/VBox/Disassembler/DisasmFormatYasm.cpp

@@ -816 +816 @@
 
                             case DISUSE_IMMEDIATE16_SX8:
-                                PUT_SZ_STRICT("strict byte ", "byte ");
+                                if (   !(pDis->fPrefix & DISPREFIX_OPSIZE)
+                                    || pDis->pCurInstr->uOpcode != OP_PUSH)
+                                    PUT_SZ_STRICT("strict byte ", "byte ");
+                                else
+                                    PUT_SZ("word ");
                                 PUT_NUM_16(pParam->uValue);
                                 break;
@@ -839 +843 @@
 
                             case DISUSE_IMMEDIATE32_SX8:
-                                PUT_SZ_STRICT("strict byte ", "byte ");
+                                if (   !(pDis->fPrefix & DISPREFIX_OPSIZE)
+                                    || pDis->pCurInstr->uOpcode != OP_PUSH)
+                                    PUT_SZ_STRICT("strict byte ", "byte ");
+                                else
+                                    PUT_SZ("dword ");
                                 PUT_NUM_32(pParam->uValue);
                                 break;
 
                             case DISUSE_IMMEDIATE64_SX8:
-                                PUT_SZ_STRICT("strict byte ", "byte ");
+                                if (   !(pDis->fPrefix & DISPREFIX_OPSIZE)
+                                    || pDis->pCurInstr->uOpcode != OP_PUSH)
+                                    PUT_SZ_STRICT("strict byte ", "byte ");
+                                else
+                                    PUT_SZ("qword ");
                                 PUT_NUM_64(pParam->uValue);
                                 break;
@@ -1237 +1249 @@
      * Check for multiple prefixes of the same kind.
      */
+    uint8_t  off1stSeg = UINT8_MAX;
+    uint8_t  offOpSize = UINT8_MAX;
+    uint8_t  offAddrSize = UINT8_MAX;
     uint32_t fPrefixes = 0;
     for (uint32_t offOpcode = 0; offOpcode < RT_ELEMENTS(pDis->abInstr); offOpcode++)
@@ -1258 +1273 @@
             case 0x64:
             case 0x65:
+                if (off1stSeg == UINT8_MAX)
+                    off1stSeg = offOpcode;
                 f = DISPREFIX_SEG;
                 break;
 
             case 0x66:
+                if (offOpSize == UINT8_MAX)
+                    offOpSize = offOpcode;
                 f = DISPREFIX_OPSIZE;
                 break;
 
             case 0x67:
+                if (offAddrSize == UINT8_MAX)
+                    offAddrSize = offOpcode;
                 f = DISPREFIX_ADDRSIZE;
                 break;
@@ -1294 +1315 @@
             &&  !DISUSE_IS_EFFECTIVE_ADDR(pDis->Param3.fUse))
             return true;
+
+        /* Yasm puts the segment prefixes before the operand prefix with no
+           way of overriding it. */
+        if (offOpSize < off1stSeg)
+            return true;
     }
 
@@ -1307 +1333 @@
     }
 
-    /* Almost all prefixes are bad. */
+    /* Almost all prefixes are bad for jumps. */
     if (fPrefixes)
     {
@@ -1343 +1369 @@
     }
 
-    /* All but the segment prefix is bad news. */
+    /* All but the segment prefix is bad news for push/pop. */
     if (fPrefixes & ~DISPREFIX_SEG)
     {
@@ -1387 +1413 @@
             case OP_XOR:
             case OP_CMP:
+                return true;
+            default:
+                break;
+        }
+    }
+
+    /* Instructions taking no address or operand which thus may be annoyingly
+       difficult to format for yasm. */
+    if (fPrefixes)
+    {
+        switch (pDis->pCurInstr->uOpcode)
+        {
+            case OP_STI:
+            case OP_STC:
+            case OP_CLI:
+            case OP_CLD:
+            case OP_CLC:
+            case OP_INT:
+            case OP_INT3:
+            case OP_INTO:
+            case OP_HLT:
+            /* Many more to can be added... */
                 return true;
             default: