Reviewers: ulan, danno, Paul Lind, kisg,
Description:
MIPS: Fix rounding in Uint8ClampedArray setter.
Port r12364 (31e40def)
Original commit message:
According to Web IDL spec, we should round to
the nearest integer, choosing the even integer
if it lies halfway between two.
BUG=
TEST=
Please review this at https://chromiumcodereview.appspot.com/10870049/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/mips/macro-assembler-mips.cc
M src/mips/simulator-mips.cc
Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc
b/src/mips/macro-assembler-mips.cc
index
515685590eaadf5347dfbd2bb85b95281219e61e..d99fbdcaa4f426f4e140ca8bb3613d0c325c3f34
100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -5398,7 +5398,7 @@ void MacroAssembler::ClampDoubleToUint8(Register
result_reg,
// In 0-255 range, round and truncate.
bind(&in_bounds);
- round_w_d(temp_double_reg, input_reg);
+ cvt_w_d(temp_double_reg, input_reg);
mfc1(result_reg, temp_double_reg);
bind(&done);
}
Index: src/mips/simulator-mips.cc
diff --git a/src/mips/simulator-mips.cc b/src/mips/simulator-mips.cc
index
66d0da71fa4260e086b77b99f8f3773466db5d44..77d64f0782a3c832faa3be86a505b3633d7a1386
100644
--- a/src/mips/simulator-mips.cc
+++ b/src/mips/simulator-mips.cc
@@ -2068,10 +2068,15 @@ void Simulator::DecodeTypeRegister(Instruction*
instr) {
// Rounding modes are not yet supported.
ASSERT((FCSR_ & 3) == 0);
// In rounding mode 0 it should behave like ROUND.
- case ROUND_W_D: // Round double to word.
+ case ROUND_W_D: // Round double to word (round half to even).
{
double rounded = fs > 0 ? floor(fs + 0.5) : ceil(fs - 0.5);
int32_t result = static_cast<int32_t>(rounded);
+ if ((result & 1) != 0 && result - fs == 0.5) {
+ // If the number is halfway between two integers,
+ // round to the even one.
+ result--;
+ }
set_fpu_register(fd_reg, result);
if (set_fcsr_round_error(fs, rounded)) {
set_fpu_register(fd_reg, kFPUInvalidResult);
--
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