PURPOSE: To obtain the value of a mathematical built-in function in a scalar process by deciding whether a vector process or a scalar process is applied to obtain the value of the mathematical built-in function based on a mathematical function information list table.

CONSTITUTION: An option analyzing means 11 analyzes the option information and produces a mathematical built-in function information list table 111. An intermediate text deciding means 141 decides whether an intermediate text is calling a mathematical built-in function or not. If so, a selection means 142 decides whether a vector process or a scalar process is applied to obtain the value of the mathematical built-in function by reference to the table 111. Then an instruction train is produced for call of each function executing procedure via a vector instruction train production means 1421 and a pseudo vector instruc tion train production means 1422 in the vector process and the scalar process respectively. As a result, the value of the mathematical built-in finction is obtained in the scalar process.