COMPILING METHOD AND SYSTEM FOR A RULE-BASED OPTIMAL PLACEMENT OF SCALING SHIFTS

摘要

A compiling method for optimal placement of scaling shifts and a system thereof are provided to efficiently generate codes by removing the reverse effect due to the insertion of scaling shift operation. A compiler(108) is divided into a generation means(210) and back-end(220). The generation means produces intermediate codes which are internal representation by analyzing inputted source codes(109), and the back-end produces an object code(110) from the intermediate code. The generation means comprises a lexical analysis means(211), a parsing means(212), a semantic analysis means(213), an intermediate code generation means(214). The lexical analysis means separates necessary tokens from the source code. The parsing means composes the tokens according to a given grammar. The meaning analyzing mean gives meaning to the grammar found out by the parsing means. The intermediate code generation means generates an intermediate code from the source code produced through the meaning analyzing mean. The back-end part includes a transforming means(221) and a translating means(222). The transforming means transforms the intermediate code according to a correction-writing rule, and the translating means generates an object code by selecting a proper command for the object code and assigning a register to the selected command.