Request for review: 6896617: Optimize sun.nio.cs.ISO_8859_1$Encode.encodeArrayLoop() on x86

[Ulf Zibis]

Am 18.01.2013 19:26, schrieb Vladimir Kozlov:
> Here are Hotspot changes with new jtreg test:
>
> http://cr.openjdk.java.net/~kvn/6896617/webrev

Hi Vladimir,

additionnally instead:

6322   load_unsigned_short(tmp5, Address(src, len, Address::times_2, 0));
6323   testl(tmp5, 0xff00);      // check if Unicode char
6324   jccb(Assembler::notZero, L_copy_1_char_exit);
6325   movb(Address(dst, len, Address::times_1, 0), tmp5);

you could do something like:

6322   load_unsigned_byte(tmp5, Address(src, len, Address::times_2, 1));
6323   jccb(Assembler::notZero, L_copy_1_char_exit); // check if ISO-8859-1 char
6324   movb(Address(dst, len, Address::times_1, 0), Address(src, len, Address::times_2, 0));

There is no need to compare against an additional constant, just check the high-byte for 0.

... and your comment
       // check if Unicode char
is wrong, as it is always a Unicode char, so correct:
       // check if ISO-8859-1 char
Similar for lines 6245, 6269 !

-Ulf