ARM: Add instruction VFPCompareAndSetFlags to macro assembler

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
===================================================================
--- src/arm/macro-assembler-arm.cc	(revision 6244)
+++ src/arm/macro-assembler-arm.cc	(working copy)
@@ -519,13 +519,71 @@
 }
 
 
-void MacroAssembler::ClearFPSCRBits(uint32_t bits_to_clear, Register scratch) {
-  vmrs(scratch);
-  bic(scratch, scratch, Operand(bits_to_clear));
-  vmsr(scratch);
+void MacroAssembler::ClearFPSCRBits(const uint32_t bits_to_clear,
+                                    const Register scratch,
+                                    const Condition cond) {
+  vmrs(scratch, cond);
+  bic(scratch, scratch, Operand(bits_to_clear), LeaveCC, cond);
+  vmsr(scratch, cond);
 }
 
 
+void MacroAssembler::VFPCompareAndSetFlags(const DwVfpRegister src1,

[Rodolph Perfetta, 2011/01/10 14:59:36]

If the flags are cleared the intent is to read them shortly after, so the case
where scratch is used sounds redundant with VFPCompareAndLoad.

[Søren Thygesen Gjesse, 2011/01/11 12:41:52]

Done.

+                                           const DwVfpRegister src2,
+                                           const Register scratch,
+                                           const Condition cond) {
+  // Clear the Invalid cumulative exception flags if a scratch register is
+  // supplied.
+  if (!scratch.is(no_reg)) {
+    ClearFPSCRBits(kVFPInvalidExceptionBit, scratch, cond);
+  }
+
+  // Compare and move FPSCR flags to the normal condition flags.
+  vcmp(src1, src2, cond);
+  vmrs(pc, cond);
+}
+
+void MacroAssembler::VFPCompareAndSetFlags(const DwVfpRegister src1,

[Rodolph Perfetta, 2011/01/10 14:59:36]

Ditto.

[Søren Thygesen Gjesse, 2011/01/11 12:41:52]

Done.

+                                           const double src2,
+                                           const Register scratch,
+                                           const Condition cond) {
+  // Clear the Invalid cumulative exception flags if a scratch register is
+  // supplied.
+  if (!scratch.is(no_reg)) {
+    ClearFPSCRBits(kVFPInvalidExceptionBit, scratch, cond);
+  }
+
+  // Compare and move FPSCR flags to the normal condition flags.
+  vcmp(src1, src2, cond);
+  vmrs(pc, cond);
+}
+
+
+void MacroAssembler::VFPCompareAndLoadFlags(const DwVfpRegister src1,
+                                            const DwVfpRegister src2,
+                                            const Register fpscr_flags,
+                                            const Condition cond) {
+  // Clear the Invalid cumulative exception flags (use fpscr_flags as scratch).
+  ClearFPSCRBits(kVFPInvalidExceptionBit, fpscr_flags);
+
+  // Compare and load FPSCR.
+  vcmp(src1, src2, cond);
+  vmrs(fpscr_flags);
+}
+
+void MacroAssembler::VFPCompareAndLoadFlags(const DwVfpRegister src1,
+                                            const double src2,
+                                            const Register fpscr_flags,
+                                            const Condition cond) {
+  // Clear the Invalid cumulative exception flags (use fpscr_flags as scratch).
+  ClearFPSCRBits(kVFPInvalidExceptionBit, fpscr_flags);
+
+  // Compare and load FPSCR.
+  vcmp(src1, src2, cond);
+  vmrs(fpscr_flags);
+}
+
+
 void MacroAssembler::EnterFrame(StackFrame::Type type) {
   // r0-r3: preserved
   stm(db_w, sp, cp.bit() | fp.bit() | lr.bit());