microcode, compilers, and supercomputer architecture

The problem with most compilers is that they're too clever ;-). And you don't always know what they're going to do in some circumstances (unless you wrote them yourself ;-)). I find half the time I spend with CAD tools is figuring out how to get them to do what I want - something I could do a lot quicker and more accurately by hand...

The answer (on the PERQ) _is_ defined. By default, AMUX will be set so R0 will appear on those lines. But there's actually an obscure instruction to set the AMUX as you want it. The point of that? Tracing pattern-related ALU faults.Had that instruction not existed (and it's not mentioned in some versions of the manual), you can bet I'd have been patching the binaries... Or : Should the microcode assembler stick your code all over the control store and put in (free) jumps as necessary? Or should it maintain the code as you typed it? Does it matter? Do you want to know what it's done? Often, it makes a heck of a difference... Don't get me started on the Xilinx tools. Suffice it to say, I spent enough time undoing the damage that they did to my designs. I hate computers that think they can design better than I can. They are almost always wrong ;-) -tony