Has Anyone Written PDP-8 .XOR. Code Using the MQ Register (Without the EAE)?

On Wed, Dec 23, 2015 at 10:14 PM, Christian Gauger-Cosgrove < captainkirk359 at gmail.com> wrote: ? ? ?OOPS! The LAST INSTRUCTION SHOULD BE TAD ARGTWO ! Starts with a clear AC, ends with AC containing argone .xor. argtwo. Neither argone nor argtwo are modified. Sorry, too much transcribing from notes about notes, etc. :-). This is a fragment from a larger topic about the TD8E. If you start with a CMA in front of the code and a CMA at then end, you have the ARGONE .EQU. ARGTWO, but that's even longer. The larger argument is that you need not calculate .equ. every 12 bits because on a DECtape, you can combine them halfs-wise at the end and then invert the six-bit result to write on the tape [or compare what you read Thus, each word loop is two instructions shorter and you can combine if you are clever in about one extra instruction but 1 or more total cycles less [for a net gain of one instruction and a little bit of time at the most critical point and a bit more at the slightly less critical points. The original discussion is that since the TD8E is for the Omnibus only, why not see if the MQ can be helpful. It seems not in the end because it takes even longer ironically [and a few more instructions, etc.] However, BSW will likely help in that separate "sticky" point to some small extent. [The overall topic is beefing up a TD8E in every way possible to make the real-world tape [not the SIMH] be more free of tape/cleanliness/guide/wear/tape-wear issues that can make the wost-case jitter problems come dangerously close to failing. When all the hardware and media are new, it's less of a concern.. However, there are actual systems running the hardware and some predictable problems. I'm just pursuing the theoretical [and practical] software issues, etc. [Can't go up one "level" in why just yet; a few already know why, but that's all I am prepared to say for now.] cjl [I found one of my own posts on-line from back in the day, and was trying to pursue it.]? -- "In the future, OS/2 will be on everyone's desktop" Bill Gates, 1992