Comtrol eCos - Manual (Page 340)

Chapter 11. Porting Guide
Note: Some CPU variants may require specific compiler support. That support must be in place before you
can undertake the eCos variant port.
HAL Variant CDL
The CDL in a variant HAL tends to depend on the exact functionality supported by the variant. If it implements
some of the devices described in the platform HAL, then the CDL for those will be here rather than there (for
example the real-time clock).
There may also be CDL to select options in the architecture HAL to configure it to a particular architectural variant.
Each variant needs an entry in the ecos.db file. This is the one for the SH3:
package CYGPKG_HAL_SH_SH3 {
alias { "SH3 architecture" hal_sh_sh3 }
directory hal/sh/sh3
script hal_sh_sh3.cdl
hardware
description "
The SH3 (SuperH 3) variant HAL package provides generic
support for SH3 variant CPUs."
}
As you can see, it is very similar to the platform entry.
The variant CDL file will contain a package entry named for the architecture and variant, matching the package
name in the
ecos.db file. Here is the initial part of the MIPS VR4300 CDL file:
cdl_package CYGPKG_HAL_MIPS_VR4300 {
display "VR4300 variant"
parent CYGPKG_HAL_MIPS
implements CYGINT_HAL_MIPS_VARIANT
hardware
include_dir cyg/hal
define_header hal_mips_vr4300.h
description "
The VR4300 variant HAL package provides generic support
for this processor architecture. It is also necessary to
select a specific target platform HAL package."
This defines the package, placing it under the MIPS architecture package in the hierarchy. The implements line in-
dicates that this is a MIPS variant. The architecture package uses this to check that exactly one variant is configured
in.
The variant defines some options that cause the architecture HAL to configure itself to support this variant.
cdl_option CYGHWR_HAL_MIPS_64BIT {
display "Variant 64 bit architecture support"
calculated 1
}
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