MIPS: Implement missing functions in regexp-macro-assembler.

src/mips/regexp-macro-assembler-mips.cc

Index: src/mips/regexp-macro-assembler-mips.cc
diff --git a/src/mips/regexp-macro-assembler-mips.cc b/src/mips/regexp-macro-assembler-mips.cc
index dde4a65a9ead81d51a3078317f69b88c09578837..0d8ae972b46ce30c6c2d93e22c707aeb788e6415 100644
--- a/src/mips/regexp-macro-assembler-mips.cc
+++ b/src/mips/regexp-macro-assembler-mips.cc
@@ -478,7 +478,10 @@ void RegExpMacroAssemblerMIPS::CheckNotCharacterAfterMinusAnd(
     uc16 minus,
     uc16 mask,
     Label* on_not_equal) {
-  UNIMPLEMENTED_MIPS();
+  ASSERT(minus < String::kMaxUtf16CodeUnit);
+  __ Subu(a0, current_character(), Operand(minus));
+  __ And(a0, a0, Operand(mask));
+  BranchOrBacktrack(on_not_equal, ne, a0, Operand(c));
 }