h6. [[Portable]] h6(. » [[Portable SWI Calls|SWI Calls]] h6((. » [[Portable_Speed2]] h6(((. » Portable_Speed2 6 h2. Portable_Speed2 6 h5. (SWI &42FCE) |_<^{width:4em}. Entry | | |<^. R0 |<^. 6 (Reason code) | |<^. R1 |<^. CPU speed in MHz | |_<^{width:4em}. Exit | | |<^. R0 |<^. Corresponding speed index | h4. Use The purpose of this call is to convert a CPU clock rate from a MHz value to a speed index. If the input value of R1 does not match an available speed, the index of the next lowest available speed will be returned. If R1 is lower than the lowest available speed, 0 (the slowest possible speed) will be returned. h4. Notes Due to hardware restrictions or for performance reasons, most systems will only support a limited number of CPU clock rates. This call, along with [[Portable_Speed2 4]] and [[Portable_Speed2 5]] allow the user to enumerate the list of available clock rates. Index 0 is always the slowest available speed, and (return value of [[Portable_Speed2 4]])-1 is always the highest available speed. To set the CPU speed, see [[Portable_Speed2 2]] or [[Portable_Speed2 8]] (to set the desired 'slow' and 'fast' speeds), and [[Portable_Speed]] (to switch between the configured 'slow' and 'fast' speeds). h4. See also * [[Portable_Speed]] * [[Portable_Speed2]] * [[Portable_Speed2 2]] * [[Portable_Speed2 4]] * [[Portable_Speed2 5]] * [[Portable_Speed2 8]] * [[Portable SWI Calls]]