Update and improve support for ARMv7 bitfield instructions....

src/arm/disasm-arm.cc

Index: src/arm/disasm-arm.cc
===================================================================
--- src/arm/disasm-arm.cc	(revision 4740)
+++ src/arm/disasm-arm.cc	(working copy)
@@ -401,6 +401,20 @@
       PrintCondition(instr);
       return 4;
     }
+    case 'f': {  // 'f: bitfield instructions - v7 and above.
+      uint32_t lsbit = instr->Bits(11, 7);
+      uint32_t width = instr->Bits(20, 16) + 1;
+      if (instr->Bit(21) == 0) {
+        // BFC/BFI:
+        // Bits 20-16 represent most-significant bit. Covert to width.
+        width -= lsbit;
+        ASSERT(width > 0);
+      }
+      ASSERT((width + lsbit) <= 32);
+      out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
+                                           "#%d, #%d", lsbit, width);
+      return 1;
+    }
     case 'h': {  // 'h: halfword operation for extra loads and stores
       if (instr->HasH()) {
         Print("h");
@@ -446,16 +460,6 @@
         out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
                                              "%d", instr->Offset12Field());
         return 5;
-      } else if ((format[3] == '1') && (format[4] == '6')) {
-        ASSERT(STRING_STARTS_WITH(format, "off16to20"));
-        out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
-                                           "%d", instr->Bits(20, 16) +1);
-        return 9;
-      } else if (format[3] == '7') {
-        ASSERT(STRING_STARTS_WITH(format, "off7to11"));
-        out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
-                                            "%d", instr->ShiftAmountField());
-        return 8;
       } else if (format[3] == '0') {
         // 'off0to3and8to19 16-bit immediate encoded in bits 19-8 and 3-0.
         ASSERT(STRING_STARTS_WITH(format, "off0to3and8to19"));
@@ -882,13 +886,29 @@
     case 3: {
       if (instr->HasW() && (instr->Bits(6, 4) == 0x5)) {
         uint32_t widthminus1 = static_cast<uint32_t>(instr->Bits(20, 16));
-        uint32_t lsbit = static_cast<uint32_t>(instr->ShiftAmountField());
+        uint32_t lsbit = static_cast<uint32_t>(instr->Bits(11, 7));
         uint32_t msbit = widthminus1 + lsbit;
         if (msbit <= 31) {
-          Format(instr, "ubfx'cond 'rd, 'rm, #'off7to11, #'off16to20");
+          if (instr->Bit(22)) {
+            Format(instr, "ubfx'cond 'rd, 'rm, 'f");
+          } else {
+            Format(instr, "sbfx'cond 'rd, 'rm, 'f");
+          }
         } else {
           UNREACHABLE();
         }
+      } else if (!instr->HasW() && (instr->Bits(6, 4) == 0x1)) {
+        uint32_t lsbit = static_cast<uint32_t>(instr->Bits(11, 7));
+        uint32_t msbit = static_cast<uint32_t>(instr->Bits(20, 16));
+        if (msbit >= lsbit) {
+          if (instr->RmField() == 15) {
+            Format(instr, "bfc'cond 'rd, 'f");
+          } else {
+            Format(instr, "bfi'cond 'rd, 'rm, 'f");
+          }
+        } else {
+          UNREACHABLE();
+        }
       } else {
         Format(instr, "'memop'cond'b 'rd, ['rn, +'shift_rm]'w");
       }