PPC: Enable unaligned access and clean up the use of UNALIGNED_ACCESSES

src/ppc/constants-ppc.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PPC_CONSTANTS_PPC_H_
 #define V8_PPC_CONSTANTS_PPC_H_
 
 #include <stdint.h>
 
 #include "src/base/logging.h"
@@ skipping 223 matching lines @@
   STHUX = 439 << 1,    // store half-word w/ update x-form
   ORX = 444 << 1,      // Or
   DIVDU = 457 << 1,    // Divide Double Word Unsigned
   DIVWU = 459 << 1,    // Divide Word Unsigned
   MTSPR = 467 << 1,    // Move to Special-Purpose-Register
   DIVD = 489 << 1,     // Divide Double Word
   DIVW = 491 << 1,     // Divide Word
   POPCNTD = 506 << 1,  // Population Count Doubleword
 
   // Below represent bits 10-1  (any value >= 512)
+  LDBRX = 532 << 1,   // load double word byte reversed w/ x-form
+  LWBRX = 534 << 1,   // load word byte reversed w/ x-form
   LFSX = 535 << 1,    // load float-single w/ x-form
   SRWX = 536 << 1,    // Shift Right Word
   SRDX = 539 << 1,    // Shift Right Double Word
   LFSUX = 567 << 1,   // load float-single w/ update x-form
   SYNC = 598 << 1,    // Synchronize
   LFDX = 599 << 1,    // load float-double w/ x-form
   LFDUX = 631 << 1,   // load float-double w/ update X-form
   STFSX = 663 << 1,   // store float-single w/ x-form
   STFSUX = 695 << 1,  // store float-single w/ update x-form
   STFDX = 727 << 1,   // store float-double w/ x-form
   STFDUX = 759 << 1,  // store float-double w/ update x-form
+  LHBRX = 790 << 1,   // load half word byte reversed w/ x-form
   SRAW = 792 << 1,    // Shift Right Algebraic Word
   SRAD = 794 << 1,    // Shift Right Algebraic Double Word
   SRAWIX = 824 << 1,  // Shift Right Algebraic Word Immediate
   SRADIX = 413 << 2,  // Shift Right Algebraic Double Word Immediate
   EXTSH = 922 << 1,   // Extend Sign Halfword
   EXTSB = 954 << 1,   // Extend Sign Byte
   ICBI = 982 << 1,    // Instruction Cache Block Invalidate
   EXTSW = 986 << 1    // Extend Sign Word
 };
 
@@ skipping 325 matching lines @@
   // Lookup the register number for the name provided.
   static int Number(const char* name);
 
  private:
   static const char* names_[kNumDoubleRegisters];
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PPC_CONSTANTS_PPC_H_