Revision: 14099
Author: [email protected]
Date: Thu Mar 28 14:17:02 2013
Log: MIPS: Fix register usage in softfloat code path.
BUG=none
TEST=mjsunit/math-floor-part2.js
Review URL: https://codereview.chromium.org/12413032
Patch from Balazs Kilvady <[email protected]>.
http://code.google.com/p/v8/source/detail?r=14099
Modified:
/branches/bleeding_edge/src/mips/code-stubs-mips.cc
=======================================
--- /branches/bleeding_edge/src/mips/code-stubs-mips.cc Thu Mar 28 05:43:19
2013
+++ /branches/bleeding_edge/src/mips/code-stubs-mips.cc Thu Mar 28 14:17:02
2013
@@ -684,6 +684,8 @@
Register scratch1,
Register scratch2,
Label* not_number) {
+ ASSERT(!object.is(dst1) && !object.is(dst2));
+
__ AssertRootValue(heap_number_map,
Heap::kHeapNumberMapRootIndex,
"HeapNumberMap register clobbered.");
@@ -878,6 +880,10 @@
ASSERT(!heap_number_map.is(object) &&
!heap_number_map.is(scratch1) &&
!heap_number_map.is(scratch2));
+ // ARM uses pop/push and Ldlr to save dst_* and probably object
registers in
+ // softfloat path. On MIPS there is no ldlr, 1st lw instruction may
overwrite
+ // object register making the 2nd lw invalid.
+ ASSERT(!object.is(dst_mantissa) && !object.is(dst_exponent));
Label done, obj_is_not_smi;
@@ -914,49 +920,24 @@
if (destination == kCoreRegisters) {
__ Move(dst_mantissa, dst_exponent, double_dst);
}
-
} else {
- ASSERT(!scratch1.is(object) && !scratch2.is(object));
// Load the double value in the destination registers.
- bool save_registers = object.is(dst_mantissa) ||
object.is(dst_exponent);
- if (save_registers) {
- // Save both output registers, because the other one probably holds
- // an important value too.
- __ Push(dst_exponent, dst_mantissa);
- }
__ lw(dst_exponent, FieldMemOperand(object,
HeapNumber::kExponentOffset));
__ lw(dst_mantissa, FieldMemOperand(object,
HeapNumber::kMantissaOffset));
// Check for 0 and -0.
- Label zero;
__ And(scratch1, dst_exponent, Operand(~HeapNumber::kSignMask));
__ Or(scratch1, scratch1, Operand(dst_mantissa));
- __ Branch(&zero, eq, scratch1, Operand(zero_reg));
+ __ Branch(&done, eq, scratch1, Operand(zero_reg));
// Check that the value can be exactly represented by a 32-bit integer.
// Jump to not_int32 if that's not the case.
- Label restore_input_and_miss;
DoubleIs32BitInteger(masm, dst_exponent, dst_mantissa, scratch1,
scratch2,
- &restore_input_and_miss);
+ not_int32);
// dst_* were trashed. Reload the double value.
- if (save_registers) {
- __ Pop(dst_exponent, dst_mantissa);
- }
__ lw(dst_exponent, FieldMemOperand(object,
HeapNumber::kExponentOffset));
__ lw(dst_mantissa, FieldMemOperand(object,
HeapNumber::kMantissaOffset));
- __ Branch(&done);
-
- __ bind(&restore_input_and_miss);
- if (save_registers) {
- __ Pop(dst_exponent, dst_mantissa);
- }
- __ Branch(not_int32);
-
- __ bind(&zero);
- if (save_registers) {
- __ Drop(2);
- }
}
__ bind(&done);
@@ -2707,16 +2688,20 @@
masm, destination, right, f14, a2, a3, heap_number_map,
scratch1, scratch2, fail);
}
+ // Use scratch3 as left in LoadNumber functions to avoid
overwriting of
+ // left (a0) register.
+ __ mov(scratch3, left);
+
// Load left operand to f12 or a0/a1. This keeps a0/a1 intact if it
// jumps to |miss|.
if (left_type == BinaryOpIC::INT32) {
FloatingPointHelper::LoadNumberAsInt32Double(
- masm, left, destination, f12, f16, a0, a1, heap_number_map,
+ masm, scratch3, destination, f12, f16, a0, a1,
heap_number_map,
scratch1, scratch2, f2, miss);
} else {
Label* fail = (left_type == BinaryOpIC::NUMBER) ? miss :
not_numbers;
FloatingPointHelper::LoadNumber(
- masm, destination, left, f12, a0, a1, heap_number_map,
+ masm, destination, scratch3, f12, a0, a1, heap_number_map,
scratch1, scratch2, fail);
}
}
--
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