1 Zephyr/Cedar BUILDROM

     2 2003/09/03

     3 

     4 BUILDROM has been extended to support the building of 'mostly-thumb' ROMs and mixed ROMs.

     5 

     6 1. Mostly Thumb ROMs.

     7 

     8 In Cedar for Zephyr BUILDROM supports the following macros for

     9 specifying which build to construct the ROM from:

    10 	   _ARM4 - The ARM4 build (eventually this will be removed)

    11 	   _ARM4T - The 'mostly-thumb' ARM4T.

    12 

    13 2. Mixed ROMs

    14 

    15 Mixed ROMs have a kernel built for a different ABI than that targeted

    16 by user-side code. In practice this means an EABI kernel and GCC98r2

    17 user-side code. By default BUILDROM use the same ABI for the kernel as

    18 specified for user-side code (i.e. one of ARM4 or ARM4T). The default

    19 kernel ABI can be overriden by supplying the appropriate value for

    20 _KABI in BUILDROM's commandline e.g. -D_KABI=ARMV5.

    21 

    22 The following example builds a 'mostly thumb' techview ROM with an

    23 EABI kernel compiled specifically for XScale:

    24 

    25      buildrom lubbock -D_ARM4T -D_KABI=XSCALE -o\epoc32\techview.arm4t.xscale.img \epoc32\rom\include\techview

    26 

    27 The above example shows that the EABI kernel does not have to be the

    28 default ARMV5 build. BUILDROM supports customizations of the default

    29 ARMV5 build. It is also worth noting that the XScale build does not

    30 have to be complete. If BUILDROM cannot find an XScale file it will

    31 look for the equivalent file from the build that has been

    32 customized. Currently this will always be ARMV5, since this is the

    33 only build that supports customization at this time.