Re: Target options for gcc
Greg Ungerer <[email protected]>
| Newsgroups | gmane.comp.hardware.motorola.microcontrollers.coldfire |
|---|---|
| Message-ID | <[email protected]> |
Hi David, David Brown wrote: > Greg Ungerer wrote: >> Hi Bob, >> >> Bob Brusa wrote: >>> On Tue, 08 Jan 2008 17:43:24 +0100, Seymour David >>> <[email protected]> wrote: > <snip> >> Traditionally the uClinux kernel for the 5282 has used the -m5307 >> switch - apparently its code instruction level timing tables in gcc >> are closer to that of the 5282 that the default -m5200 switch. >> >> But you can use -m5200 on any of the ColdFire family members. >> >> >>>> The manufacturer of the COBRA5285-Board I am using provided >>>> examples. One >>>> of them uses the option -m5307 which is however nowhere documented. >> >> Looks like who ever merged the gcc changes that support those >> newer switches didn't update the manual. Even the latest 4.2.2 >> doco doesn't list anything other than -m5200 (it does list the >> other new uClinux switches like -msep-data though...). >> > > If you use "m68k-elf-gcc -v --help", you'll see a list of all the > command line switches for the gcc you are using. In particular, if you > get a recent build from CodeSourcery, there is direct support for a wide > range of Coldfires - the switch you want is "-mcpu=5282". In keeping > with many other embedded gcc ports, CodeSourcery use the "-mcpu=" flag > to make it easier to choose the exact instruction set and code > generation options appropriate for different devices, as well as helping > to get the correct linker file and libraries for the device. Thus you > should not specify "-m" options directly, but use the "-mcpu=" for your > device. > > Since CodeSourcery work on their own branches of gcc, they can get > changes into the code much faster than the standard FSF gcc tree, and > thus their versions have newer features. These all get merged back to > the FSF (several of the official gcc lead developers work at > > CodeSourcery), but because changes must be tested clean on such a range > of devices, it takes much longer - the "-mcpu=" flags will be in the FSF > gcc at version 4.3, while CodeSourcery has them on 4.2-47. > > > Incidentally, the official gnu gcc docs for 4.1.1 *are* available on the > gcc website - it's just that there is no direct link from the > documentation page: > > http://gcc.gnu.org/onlinedocs/gcc-4.1.1/gcc/ Perhaps not recommended for use, but still no versions of the documentation list the -mxxxx options for the 5xx. Even though they extensively list the other 68xxx varients. Regards Greg -- ------------------------------------------------------------------------ Greg Ungerer -- Chief Software Dude EMAIL: [email protected] SnapGear -- a Secure Computing Company PHONE: +61 7 3435 2888 825 Stanley St, FAX: +61 7 3891 3630 Woolloongabba, QLD, 4102, Australia WEB: http://www.SnapGear.com --- [email protected] Send a post to the list. [email protected] Join the list. [email protected] Join the list in digest mode. [email protected] Leave the list.