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6.57.11.1 Argument Types

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
uh unsigned short No an unsigned halfword
uw1 unsigned int No an unsigned word
sw1 int No a signed word
uw2 unsigned long long No an unsigned doubleword
sw2 long long No a signed doubleword
const int Yes an integer constant
acc int Yes an ACC register number
iacc int 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 uh, uw1, sw1, uw2 and 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 selects 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.