ARM: Add PostIndex support to Ldrd/Strd macro fallback code....

src/arm/macro-assembler-arm.cc

 // Copyright 2011 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 636 matching lines @@
 }
 
 
 void MacroAssembler::Ldrd(Register dst1, Register dst2,
                           const MemOperand& src, Condition cond) {
   ASSERT(src.rm().is(no_reg));
   ASSERT(!dst1.is(lr));  // r14.
   ASSERT_EQ(0, dst1.code() % 2);
   ASSERT_EQ(dst1.code() + 1, dst2.code());
 
+  // V8 does not use this addressing mode, so the fallback code
+  // below doesn't support it yet.
+  ASSERT((src.am() != PreIndex) && (src.am() != NegPreIndex));
+
   // Generate two ldr instructions if ldrd is not available.
   if (CpuFeatures::IsSupported(ARMv7)) {
     CpuFeatures::Scope scope(ARMv7);
     ldrd(dst1, dst2, src, cond);
   } else {
     MemOperand src2(src);

[Søren Thygesen Gjesse, 2011/06/14 10:44:01]

Please move the declaration of src2 closer to where it is used. I suggest
declaring it twice just before each src2.set_offset(...), as there is one if
branch where it is not used.

[m.m.capewell, 2011/06/22 12:42:36]

Done.

-    src2.set_offset(src2.offset() + 4);
-    if (dst1.is(src.rn())) {
-      ldr(dst2, src2, cond);
-      ldr(dst1, src, cond);
-    } else {
-      ldr(dst1, src, cond);
-      ldr(dst2, src2, cond);
+    if ((src.am() == Offset) || (src.am() == NegOffset)) {
+      src2.set_offset(src2.offset() + 4);
+      if (dst1.is(src.rn())) {
+        ldr(dst2, src2, cond);
+        ldr(dst1, src, cond);
+      } else {
+        ldr(dst1, src, cond);
+        ldr(dst2, src2, cond);
+      }
+    } else {  // PostIndex or NegPostIndex.

[Søren Thygesen Gjesse, 2011/06/14 10:44:01]

Please assert PostIndex or NegPostIndex.

[m.m.capewell, 2011/06/22 12:42:36]

Done.

+      if (dst1.is(src.rn())) {
+        ldr(dst2, MemOperand(src.rn(), 4, Offset), cond);
+        ldr(dst1, src, cond);
+      } else {
+        src2.set_offset(src2.offset() - 4);
+        ldr(dst1, MemOperand(src.rn(), 4, PostIndex), cond);
+        ldr(dst2, src2, cond);
+      }
     }
   }
 }
 
 
 void MacroAssembler::Strd(Register src1, Register src2,
                           const MemOperand& dst, Condition cond) {
   ASSERT(dst.rm().is(no_reg));
   ASSERT(!src1.is(lr));  // r14.
   ASSERT_EQ(0, src1.code() % 2);
   ASSERT_EQ(src1.code() + 1, src2.code());
 
+  // V8 does not use this addressing mode, so the fallback code
+  // below doesn't support it yet.
+  ASSERT((dst.am() != PreIndex) && (dst.am() != NegPreIndex));
+
   // Generate two str instructions if strd is not available.
   if (CpuFeatures::IsSupported(ARMv7)) {
     CpuFeatures::Scope scope(ARMv7);
     strd(src1, src2, dst, cond);
   } else {
     MemOperand dst2(dst);
-    dst2.set_offset(dst2.offset() + 4);
-    str(src1, dst, cond);
-    str(src2, dst2, cond);
+    if ((dst.am() == Offset) || (dst.am() == NegOffset)) {
+      dst2.set_offset(dst2.offset() + 4);
+      str(src1, dst, cond);
+      str(src2, dst2, cond);
+    } else {  // PostIndex or NegPostIndex.

[Søren Thygesen Gjesse, 2011/06/14 10:44:01]

Please assert PostIndex or NegPostIndex.

[m.m.capewell, 2011/06/22 12:42:36]

Done.

+      dst2.set_offset(dst2.offset() - 4);
+      str(src1, MemOperand(dst.rn(), 4, PostIndex), cond);
+      str(src2, dst2, cond);
+    }
   }
 }
 
 
 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);
@@ skipping 2456 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM