The HAL has been implemented according to the following general +principles:
The HAL is implemented in C and assembler, although the + eCos kernel is largely implemented in C++. + This is to permit the HAL the widest possible + applicability.
All interfaces to the HAL are implemented by + CPP macros. This allows them to be implemented as inline + C code, inline assembler or function calls to external C + or assembler code. This allows the most efficient + implementation to be selected without affecting the + interface. It also allows them to be redefined if the + platform or variant HAL needs to replace or enhance a definition + from the architecture HAL.
The HAL provides simple, portable mechanisms for dealing +with the hardware of a wide range of architectures and platforms. +It is always possible to bypass the HAL and program the hardware +directly, but this may lead to a loss of portability.