By Herbert J. Bernstein

© Copyright 2000 Herbert J. Bernstein

The flow of control in imperative programming languages is normally through sequences of statements. Control structures allow for changes in that default flow of control.

• Go to and instruction modification
• Labeling statements
  • Absolute numeric addresses
  • Symbolic numeric addresses
  • Mnemonic symbolic addresses
• Conditional branch instructions
  • If accumulator relop 0 goto label
  • If expression goto label
• Vectored branch instructions
  • Go to A[i]
  • Fortran computed GOTO
    GOTO (lab1, lab2, lab3, ..., labn), expression
• Fortran 3 branch
  IF (expression) lab_neg,lab_zero,lab_pos
• Logical IF
  IF (expression) statement
• Block IF
  IF (expression) THEN
  statements
  ELSE
  statements
  ENDIF
• ElseIf
• Dangling Else
• Case statements
• Loops
• Counters
• Managing the interaction with blocks