MIPS: Reland "Handle non-power-of-2 divisors in division-like operations".

src/mips/macro-assembler-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5688 matching lines @@
         opcode == BEQL ||
         opcode == BNEL ||
        opcode == BLEZL ||
        opcode == BGTZL);
   opcode = (cond == eq) ? BEQ : BNE;
   instr = (instr & ~kOpcodeMask) | opcode;
   masm_.emit(instr);
 }
 
 
+void MacroAssembler::FlooringDiv(Register result,
+                                 Register dividend,
+                                 int32_t divisor) {
+  ASSERT(!dividend.is(result));
+  ASSERT(!dividend.is(at));
+  ASSERT(!result.is(at));
+  MultiplierAndShift ms(divisor);
+  li(at, Operand(ms.multiplier()));
+  Mult(dividend, Operand(at));
+  mfhi(result);
+  if (divisor > 0 && ms.multiplier() < 0) {
+    Addu(result, result, Operand(dividend));
+  }
+  if (divisor < 0 && ms.multiplier() > 0) {
+    Subu(result, result, Operand(dividend));
+  }
+  if (ms.shift() > 0) {
+    sra(result, result, ms.shift());
+  }
+}
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS