s390x: Add CountTrailingZerosU32/U64 to TFAssem

Change-Id: Idf653061a88beb348fa13e907932ca68f2d6d05b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2685366Reviewed-by: Milad Fa <mfarazma@redhat.com>
Commit-Queue: Junliang Yan <junyan@redhat.com>
Cr-Commit-Position: refs/heads/master@{#72636}

src/codegen/s390/macro-assembler-s390.cc

@@ -4712,6 +4712,47 @@ void TurboAssembler::CountLeadingZerosU64(Register dst, Register src,
   mov(dst, scratch_pair);
 }
 
+void TurboAssembler::CountTrailingZerosU32(Register dst, Register src,
+                                           Register scratch_pair) {
+  Register scratch0 = scratch_pair;
+  Register scratch1 = Register::from_code(scratch_pair.code() + 1);
+  DCHECK(!AreAliased(dst, scratch0, scratch1));
+  DCHECK(!AreAliased(src, scratch0, scratch1));
+
+  Label done;
+  // Check if src is all zeros.
+  ltr(scratch1, src);
+  mov(dst, Operand(32));
+  beq(&done);
+  llgfr(scratch1, scratch1);
+  lcgr(scratch0, scratch1);
+  ngr(scratch1, scratch0);
+  flogr(scratch0, scratch1);
+  mov(dst, Operand(63));
+  SubS64(dst, scratch0);
+  bind(&done);
+}
+
+void TurboAssembler::CountTrailingZerosU64(Register dst, Register src,
+                                           Register scratch_pair) {
+  Register scratch0 = scratch_pair;
+  Register scratch1 = Register::from_code(scratch_pair.code() + 1);
+  DCHECK(!AreAliased(dst, scratch0, scratch1));
+  DCHECK(!AreAliased(src, scratch0, scratch1));
+
+  Label done;
+  // Check if src is all zeros.
+  ltgr(scratch1, src);
+  mov(dst, Operand(64));
+  beq(&done);
+  lcgr(scratch0, scratch1);
+  ngr(scratch0, scratch1);
+  flogr(scratch0, scratch0);
+  mov(dst, Operand(63));
+  SubS64(dst, scratch0);
+  bind(&done);
+}
+
 }  // namespace internal
 }  // namespace v8
 

src/codegen/s390/macro-assembler-s390.h

@@ -495,9 +495,6 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
   void Popcnt64(Register dst, Register src);
 #endif
 
-  // CountLeadingZeros will corrupt the scratch register pair (eg. r0:r1)
-  void CountLeadingZerosU32(Register dst, Register src, Register scratch_pair);
-  void CountLeadingZerosU64(Register dst, Register src, Register scratch_pair);
   void mov(Register dst, const Operand& src);
   void mov(Register dst, Register src);
 
@@ -1030,6 +1027,16 @@ class V8_EXPORT_PRIVATE TurboAssembler : public TurboAssemblerBase {
   void DecompressAnyTagged(Register destination, MemOperand field_operand);
   void DecompressAnyTagged(Register destination, Register source);
 
+  // CountLeadingZeros will corrupt the scratch register pair (eg. r0:r1)
+  void CountLeadingZerosU32(Register dst, Register src,
+                            Register scratch_pair = r0);
+  void CountLeadingZerosU64(Register dst, Register src,
+                            Register scratch_pair = r0);
+  void CountTrailingZerosU32(Register dst, Register src,
+                             Register scratch_pair = r0);
+  void CountTrailingZerosU64(Register dst, Register src,
+                             Register scratch_pair = r0);
+
  private:
   static const int kSmiShift = kSmiTagSize + kSmiShiftSize;