So I have produced a corrected version, which generates a hex file which is absolutely identical to the RCA listing in MPM-203. I have uploaded it to my [RCA CDP18S020] board [with an original RCA UT4 ROM], and it appears to work perfectly OK (aside from the usual foibles with UT4 send/echo parity issues, plus it likes to send backspace characters which delete bits of the line if the terminal emulator is not set up correctly). I have included the assembly file, listing file and hex file to this mail, and have added my comments to clearly highlight the differences from your original version.

Robert Coward, writing to Herb Johnson
June 17 2020

