The arguments to the built-in functions can be divided into three groups: register numbers, compile-time constants and run-time values. In order to make this classification clear at a glance, the arguments and return values are given the following pseudo types:
|Pseudo type||Real C type||Constant?||Description
|No||an unsigned halfword
|No||an unsigned word
|No||a signed word
|No||an unsigned doubleword
|No||a signed doubleword
|Yes||an integer constant
|Yes||an ACC register number
|Yes||an IACC register number
These pseudo types are not defined by GCC, they are simply a notational convenience used in this manual.
Arguments of type
sw2 are evaluated at run time. They correspond to
register operands in the underlying FR-V instructions.
const arguments represent immediate operands in the underlying
FR-V instructions. They must be compile-time constants.
acc arguments are evaluated at compile time and specify the number
of an accumulator register. For example, an
acc argument of 2
will select the ACC2 register.
iacc arguments are similar to
acc arguments but specify the
number of an IACC register. See see Other Built-in Functions
for more details.