-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The Sunday 2006-02-19 at 19:27 -0500, ken wrote:
"-mcpu=pentium4m" in CFLAGS. Makes smaller and faster code.
I think you would get better perfomance with "-march=pentium4m" instead.
Actually, I have both set the same. (I set it in some config file a long time ago and don't even remember anymore where I did it.)
Yeah, according to the gcc manpage, it's redundant this way:
Not really.
-march=cpu-type Generate instructions for the machine type cpu-type. The choices for cpu-type are the same as for -mcpu. Moreover, spec- ifying -march=cpu-type implies -mcpu=cpu-type.
but it doesn't give a non-redundant way to specify it. :/
I'm going by memory, no, it is not redundant, both options are... hold on... but... heck, they have changed the options again. -mcpu was what - -mtune is now. Obsserve, for an old gcc-2.95.3: `-mcpu=CPU TYPE' Assume the defaults for the machine type CPU TYPE when scheduling instructions. The choices for CPU TYPE are: `-march=CPU TYPE' Generate instructions for the machine type CPU TYPE. The choices for CPU TYPE are the same as for `-mcpu'. Moreover, specifying `-march=CPU TYPE' implies `-mcpu=CPU TYPE'. In gcc 3.3.5 it says instead: `-mtune=CPU_TYPE' Set only the instruction scheduling parameters for machine type CPU_TYPE. The instruction set is not changed. `-mcpu=CPU-TYPE' Tune to CPU-TYPE everything applicable about the generated code, except for the ABI and the set of available instructions. The choices for CPU-TYPE are: `-march=CPU-TYPE' Generate instructions for the machine type CPU-TYPE. The choices for CPU-TYPE are the same as for `-mcpu'. Moreover, specifying `-march=CPU-TYPE' implies `-mcpu=CPU-TYPE'. Things have changed... I didn't notice this before :-( Anyway, "march" is the "boss" option, it seems. As it was time ago. - -- Cheers, Carlos Robinson -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFD+RmQtTMYHG2NR9URAjXbAJwMN87B0Rvn6NaIAUp8y+rnBJFs/wCfQUOO A/83sXInBNPXQol01MCRAAA= =2f2K -----END PGP SIGNATURE-----