Saves callee-saved fpu registers on MIPS.

runtime/vm/stub_code_mips.cc

Index: runtime/vm/stub_code_mips.cc
===================================================================
--- runtime/vm/stub_code_mips.cc	(revision 26893)
+++ runtime/vm/stub_code_mips.cc	(working copy)
@@ -911,13 +911,22 @@
 
   // Save new context and C++ ABI callee-saved registers.
   const intptr_t kNewContextOffset =
-      -(1 + kAbiPreservedCpuRegCount) * kWordSize;
+      -(1 + kAbiPreservedCpuRegCount + kAbiPreservedFpuRegCount) * kWordSize;
+  const intptr_t kPreservedRegSpace =
+      (kAbiPreservedCpuRegCount + kAbiPreservedFpuRegCount + 3) * kWordSize;

[regis, 2013/08/30 01:53:39]

What are these 3 registers you save? 1 is the new context, but what are the
other 2? These must be top exit frame and old context. A comment would help.
Also a defined constant for 3 that you can reuse several times below would be
cleaner. This predated this cl...

[zra, 2013/09/03 15:09:11]

Done.

 
-  __ addiu(SP, SP, Immediate(-(3 + kAbiPreservedCpuRegCount) * kWordSize));
+  __ addiu(SP, SP, Immediate(-kPreservedRegSpace));
   for (int i = S0; i <= S7; i++) {
     Register r = static_cast<Register>(i);
     __ sw(r, Address(SP, (i - S0 + 3) * kWordSize));
   }
+
+  for (intptr_t i = F20; i <= F31; i++) {
+    FRegister r = static_cast<FRegister>(i);
+    __ swc1(r,
+        Address(SP, (kAbiPreservedCpuRegCount + 3 + i - F20) * kWordSize));
+  }
+
   __ sw(A3, Address(SP, 2 * kWordSize));
 
   // The new Context structure contains a pointer to the current Isolate
@@ -946,13 +955,13 @@
 
   // The constants kSavedContextSlotFromEntryFp and
   // kExitLinkSlotFromEntryFp must be kept in sync with the code below.
-  ASSERT(kExitLinkSlotFromEntryFp == -10);
-  ASSERT(kSavedContextSlotFromEntryFp == -11);
+  ASSERT(kExitLinkSlotFromEntryFp == -22);
+  ASSERT(kSavedContextSlotFromEntryFp == -23);
   __ sw(T0, Address(SP, 1 * kWordSize));
   __ sw(T1, Address(SP, 0 * kWordSize));
 
   // After the call, The stack pointer is restored to this location.
-  // Pushed A3, S0-7, T0, T1 = 11.
+  // Pushed A3, S0-7, F20-31, T0, T1 = 23.
 
   // Load arguments descriptor array into S4, which is passed to Dart code.
   __ lw(S4, Address(A1, VMHandles::kOffsetOfRawPtrInHandle));
@@ -1008,8 +1017,15 @@
     Register r = static_cast<Register>(i);
     __ lw(r, Address(SP, (i - S0 + 3) * kWordSize));
   }
+
+  for (intptr_t i = F20; i <= F31; i++) {
+    FRegister r = static_cast<FRegister>(i);
+    __ lwc1(r,
+        Address(SP, (kAbiPreservedCpuRegCount + 3 + i - F20) * kWordSize));

[regis, 2013/08/30 01:53:39]

3 -> named constant defined above.

[zra, 2013/09/03 15:09:11]

Done.

+  }
+
   __ lw(A3, Address(SP, 2 * kWordSize));
-  __ addiu(SP, SP, Immediate((3 + kAbiPreservedCpuRegCount) * kWordSize));
+  __ addiu(SP, SP, Immediate(kPreservedRegSpace));
 
   // Restore the frame pointer and return.
   __ LeaveStubFrameAndReturn();