1 files changed, 17 insertions, 41 deletions

diff --git a/llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.cpp b/llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.cpp
index 50d10feaae3..6a10278dc7f 100644
--- a/llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.cpp
+++ b/llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.cpp
@@ -103,6 +103,9 @@ static int modRMRequired(OpcodeType type,
   case XOPA_MAP:
     decision = &XOPA_MAP_SYM;
     break;
+  case THREEDNOW_MAP:
+    decision = &THREEDNOW_MAP_SYM;
+    break;
   }
 
   return decision->opcodeDecisions[insnContext].modRMDecisions[opcode].
@@ -147,6 +150,9 @@ static InstrUID decode(OpcodeType type,
   case XOPA_MAP:
     dec = &XOPA_MAP_SYM.opcodeDecisions[insnContext].modRMDecisions[opcode];
     break;
+  case THREEDNOW_MAP:
+    dec = &THREEDNOW_MAP_SYM.opcodeDecisions[insnContext].modRMDecisions[opcode];
+    break;
   }
 
   switch (dec->modrm_type) {
@@ -588,44 +594,11 @@ static int readPrefixes(struct InternalInstruction* insn) {
                 insn->vectorExtensionPrefix[0], insn->vectorExtensionPrefix[1],
                 insn->vectorExtensionPrefix[2]);
     }
-  } else if (byte == 0x0f) {
-    uint8_t byte1;
-
-    // Check for AMD 3DNow without a REX prefix
-    if (consumeByte(insn, &byte1)) {
-      unconsumeByte(insn);
-    } else {
-      if (byte1 != 0x0f) {
-        unconsumeByte(insn);
-        unconsumeByte(insn);
-      } else {
-        dbgprintf(insn, "Found AMD 3DNow prefix 0f0f");
-        insn->vectorExtensionType = TYPE_3DNOW;
-      }
-    }
   } else if (isREX(insn, byte)) {
     if (lookAtByte(insn, &nextByte))
       return -1;
     insn->rexPrefix = byte;
     dbgprintf(insn, "Found REX prefix 0x%hhx", byte);
-
-    // Check for AMD 3DNow with a REX prefix
-    if (nextByte == 0x0f) {
-      consumeByte(insn, &nextByte);
-      uint8_t byte1;
-
-      if (consumeByte(insn, &byte1)) {
-        unconsumeByte(insn);
-      } else {
-        if (byte1 != 0x0f) {
-          unconsumeByte(insn);
-          unconsumeByte(insn);
-        } else {
-          dbgprintf(insn, "Found AMD 3DNow prefix 0f0f");
-          insn->vectorExtensionType = TYPE_3DNOW;
-        }
-      }
-    }
   } else
     unconsumeByte(insn);
 
@@ -725,12 +698,6 @@ static int readOpcode(struct InternalInstruction* insn) {
       insn->opcodeType = XOPA_MAP;
       return consumeByte(insn, &insn->opcode);
     }
-  } else if (insn->vectorExtensionType == TYPE_3DNOW) {
-    // Consume operands before the opcode to comply with the 3DNow encoding
-    if (readModRM(insn))
-      return -1;
-    insn->opcodeType = TWOBYTE;
-    return consumeByte(insn, &insn->opcode);
   }
 
   if (consumeByte(insn, &current))
@@ -756,6 +723,17 @@ static int readOpcode(struct InternalInstruction* insn) {
         return -1;
 
       insn->opcodeType = THREEBYTE_3A;
+    } else if (current == 0x0f) {
+      dbgprintf(insn, "Found a 3dnow escape prefix (0x%hhx)", current);
+
+      // Consume operands before the opcode to comply with the 3DNow encoding
+      if (readModRM(insn))
+        return -1;
+
+      if (consumeByte(insn, &current))
+        return -1;
+
+      insn->opcodeType = THREEDNOW_MAP;
     } else {
       dbgprintf(insn, "Didn't find a three-byte escape prefix");
 
@@ -951,8 +929,6 @@ static int getID(struct InternalInstruction* insn, const void *miiArg) {
 
       if (lFromXOP3of3(insn->vectorExtensionPrefix[2]))
         attrMask |= ATTR_VEXL;
-    } else if (insn->vectorExtensionType == TYPE_3DNOW) {
-      attrMask |= ATTR_3DNOW;
     } else {
       return -1;
     }