May 22nd, 2014, 6:52 pm
QuoteOriginally posted by: outrunRegarding orthogonality, I found this that makes a clear point:QuoteThe meaning of an orthogonal feature is independent of context; the key parameters are symmetry and consistency.An example from IBM Mainframe and VAX highlights this concept. An IBM mainframe has two different instructions for adding the contents of a register to a memory cell (or another register). These statements are shown below:A Reg1, memory_cellAR Reg1, Reg2In the first case, the contents of Reg1 are added to the contents of a memory cell; the result is stored in Reg1. In the second case, the contents of Reg1 are added to the contents of another register (Reg2) and the result is stored in Reg1.In contrast to the above set of statements, VAX has only one statement for addition:ADDL operand1, operand2In this case the two operands (operand1 and operand2) can be registers, memory cells, or a combination of both; the instruction adds the contents of operand1 to the contents of operand2, storing the result in operand1.Ah VAX/VMS. Many memories.Polter,What about orthogonality and multimethods?(BTW orthog not work on VAX quadword).
Last edited by
Cuchulainn on May 21st, 2014, 10:00 pm, edited 1 time in total.