Dave Gibney wrote: <begin extract> How can Millicode be faster than the equivalent using the hardware instructions? As I understand Millicode, that is really all it is (using the hardware instructions) plus any overhead in context switching to the Millicode "environment". </end extract>
This is a common misunderstanding that has unfortunately been repeated many times. It is a radically misleading caricature. Millicode makes available many facilities not available in the HLASM. It does not make additional machine instructions available, but it does make its own powerful facilities for specifying the path pf control among them available. I have always felt some impatience with this view. If it were at all accurate it would make millicode, which goes back to the System/390, unimportant, even dispensable; and, while IBM is not infallible, it is deeply serious about its hardware investments. GIYF. To begin see (watch wrap) http://ecc.marist.edu/conf2011/materials/SlegelSystemZ_APeekUnderTheHood_Slegel_MaristECC.pdf. John Gilmore, Ashland, MA 01721 - USA
