CDC 6600 - Why so awesome?

On Tue, Jun 21, 2016 at 2:06 PM, Swift Griggs <swiftgriggs at gmail.com> wrote: > - It was RISC nearly before folks could even articulate the concept > - It used odd sized (by todays standards) register, instruction, and bus > sizes. 60 bit machine with 15/30 bit instructions. But, didn't it cause > a bunch of alignment issues for you ? > I dug into the CPU instructions for about 20 minutes and it was actually > pretty straightforward. The so-called "COMPASS" ASM code was oh-so-cool. I > can't believe they had so many of the features now considered "modern" or > "clever" (at least by me) in the 1960s! This code: The odd thing about the instruction set is that it did not have load/store instructions; load/store was a side-effect -- net register An (for n in 0-5), and the data at the memory address the register was set to was loaded into the corresponding Xn register, for n 6 or 7, the value in the Xn register was stored at the address. So the extra credit exercise is to figure out how to write a subroutine that prints out the value of all of the registers; ie. how can you save *all* of the register values to memory? -- Charles