On Thu, Mar 25, 2010 at 10:19, Ulf Zibis <ulf.zi...@gmx.de> wrote: > Am 24.03.2010 09:24, schrieb Martin Buchholz:
>> Addition of highSurrogate and lowSurrogate >> imported patch highSurrogate >> http://cr.openjdk.java.net/~martin/webrevs/openjdk7/highSurrogate >> > > Looks good. Interesting workaround on my "Note:" > I've reckoned with dropping my highSurrogate(char highCPWord, char > lowCPWord). Yeah, it's not the kind of method that tends to become a public API. If you can demonstrate a real performance advantage for highSurrogate(char,char) beyond just EUC_TW, esp in UTF_8, then we can put it into Surrogate.java. Martin > Anyway I like to note, that I use that shortcut in my EUC_TW$Decoder > twiddling. Following code: > > da[dp] = Character.highSurrogate(0x20000 + c); > results in (19 bytes): > 0x00b8ae27: add $0x20000,%ecx ;*iadd > ; - > sun.nio.cs.ext.D_21_d_narrow::dec...@98 (line 196) > 0x00b8ae2d: mov %ecx,%ebp > 0x00b8ae2f: shr $0xa,%ebp > 0x00b8ae32: add $0xd7c0,%ebp ;*isub > ; - > java.lang.Character::highsurrog...@9 (line 3343) > ; - > sun.nio.cs.ext.D_21_d_narrow::dec...@99 (line 196) > > da[dp] = Character.highSurrogate((char)0x2, c); > results in (9 bytes): > 0x00b899e7: shr $0xa,%ebp > 0x00b899ea: add $0xd840,%ebp ;*isub > ; - > java.lang.Character::highsurrog...@14 (line 3365) > ; - > sun.nio.cs.ext.D_22_d_n_fastSurrogate::dec...@97 (line 196) > > > dst.putInt(Character.highSurrogate((char)0x2, c)) << 16 | > Character.lowSurrogate(c)); > would additionally increase performance. I'm still preparing the benchmark + > disassembly. > > Those twiddling could be used in all surrogate processing charset coders, > e.g. maybe true for UTF_x. > If public, would be too useful for developers coding charset coders for > exotic charsets via java.nio.charset.spi.CharsetProvider > > -Ulf > > >
