doc/html/ref/hal-general-principles.html

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  84 NAME="HAL-GENERAL-PRINCIPLES">Chapter 8. General principles</H1
  85 ><P
  86 >The HAL has been implemented according to the following general
  87 principles:</P
  88 ><P
  89 ></P
  90 ><OL
  91 TYPE="1"
  92 ><LI
  93 ><P
  94 >             The HAL is implemented in C and assembler, although the
  95               eCos kernel is largely implemented in C&#0043;&#0043;.
  96               This is to permit the HAL the widest possible
  97               applicability.</P
  98 ></LI
  99 ><LI
 100 ><P
 101 >All interfaces to the HAL are implemented by
 102               CPP macros. This allows them to be implemented as inline
 103               C code, inline assembler or function calls to external C
 104               or assembler code. This allows the most efficient
 105               implementation to be selected without affecting the
 106               interface. It also allows them to be redefined if the
 107               platform or variant HAL needs to replace or enhance a definition
 108               from the architecture HAL.</P
 109 ></LI
 110 ><LI
 111 ><P
 112 >The HAL provides simple, portable mechanisms for dealing
 113 with the hardware of a wide range of architectures and platforms.
 114 It is always possible to bypass the HAL and program the hardware
 115 directly, but this may lead to a loss of portability. </P
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