Generalized division via multiplication.

src/x87/macro-assembler-x87.cc

 // Copyright 2012 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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/base/bits.h"
+#include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
 #include "src/cpu-profiler.h"
 #include "src/debug.h"
 #include "src/isolate-inl.h"
 #include "src/runtime.h"
 #include "src/serialize.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 3283 matching lines @@
   j(equal, found);
   mov(current, FieldOperand(current, Map::kPrototypeOffset));
   cmp(current, Immediate(factory->null_value()));
   j(not_equal, &loop_again);
 }
 
 
 void MacroAssembler::TruncatingDiv(Register dividend, int32_t divisor) {
   DCHECK(!dividend.is(eax));
   DCHECK(!dividend.is(edx));
-  MultiplierAndShift ms(divisor);
-  mov(eax, Immediate(ms.multiplier()));
+  base::MagicNumbersForDivision<uint32_t> mag =
+      base::SignedDivisionByConstant(static_cast<uint32_t>(divisor));
+  mov(eax, Immediate(mag.multiplier));
   imul(dividend);
-  if (divisor > 0 && ms.multiplier() < 0) add(edx, dividend);
-  if (divisor < 0 && ms.multiplier() > 0) sub(edx, dividend);
-  if (ms.shift() > 0) sar(edx, ms.shift());
+  bool neg = (mag.multiplier & (static_cast<uint32_t>(1) << 31)) != 0;
+  if (divisor > 0 && neg) add(edx, dividend);
+  if (divisor < 0 && !neg && mag.multiplier > 0) sub(edx, dividend);
+  if (mag.shift > 0) sar(edx, mag.shift);
   mov(eax, dividend);
   shr(eax, 31);
   add(edx, eax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X87