Document Type

Technical Report

Publication Date

Spring 3-1-1974


A basic block is a sequence of consecutive Fortran statements which must be executed consecutively; that is, if one statement in the block is executed, all are executed. Except for special cases noted in the text, a Fortran program is a catenation of basic blocks. BRNANL is the Fortran program designed to recognize basic blocks in a Fortran program. Given a Fortran program (FP) BRNANL will generate a modified Fortran program (MFP) in which a subroutine call is located at the head of every basic block. Execution of the MFP produces the same results as execution of the FP but the inserted subroutine calls permit monitoring of the execution sequences. User information for running BRNANL is presented.