Understand FixDiv in sound functions
The "Div" function in C returns both the quotient and the remainder of a division function, placing the results in a structure; so I suspect "FixDiv" does the same thing in a fixed-point format. Integer division in FB is represented by a "\" (or the "/", depending on your default; \ will be the "other one") and you can get the remainder with MOD.The "$" denotes hexadecimal; in FB, it'd be "&H".
Well, FixDiv is a toolbox division call that operates on 32-bit values (long, Fixed, or Fract). It returns a quotient whose format depends on that of the input parameters (see IM). You don't say what oldrate is defined as in the C code (I'm guessing a Fixed, which I believe is a way of representing a floating point number within a long by using the upper word as the integer portion and the lower word as the decimal portion). It does appear to be supported by FB, so a translation of the line in question would be: