"The 6502 Gets Microprogrammable Instructions" (archived link), namely
- Gordon, H T, "Decoding 650X Op Codes" Dr. Dobbs Journal of Computer Calisthenics and Orthodontia, Volume 2, Issue 7, August 1977, pages 20 thru 22.
Gordon, H T, "Decoding Efficiency and Speed" Dr. Dobbs Journal, Volume 3, Issue 2, February 1978, pages 5 thru 7.
Gordon, H T, "Software and Correction" Dr. Dobbs Journal, Volume 2, Issue 9, October 1977, pages 42 thru 44.
Gordon, H T, "Use of NOP Codes as Executable Labels" Dr. Dobbs Journal, Volume 3, Issue 8, September 1978, page 29.
Gordon, H T, "The XF and X7 Instructions of the MOS Technology 6502", BYTE, Volume 2, Number 12, December 1977, page 72.
Gupta, Yogesh M, "True Confessions: How I Relate to KIM" BYTE, Volume 1, Number 12, August 1976, pages 44 thru 48.
Moser, C W, "Add a Trap Vector for Unimplemented Op Codes" Dr. Dobbs Journal, Volume 4, Issue 1, January 1979, pages 32 thru 34.
Wozniak, Stephen, "SWEET16: The 6502 Dream Machine" BYTE, Volume 2, Number 11, November 1977, pages 150 thru 159.
I did find this index of 6502-related articles in later issues of DDJ:
- cross assemblers, ACTxx, from SORCIM [review] (S. Newberry), Aug83, 108
"Instructions of the 6800 and 6502, SBC, TSX and TXS" (B.T.G. Tan), May83, 67
program: "Faster Circles for Apples" (M.L. Pulier), Dec83, 18
programming techniques
"6502 Hacks" (M.S. Ackerman), Feb87, 24; Jun87, 122
"Code Compression with Mini-Interpreters" (N. Turner), May86, 110
registers, saving and restoring [letter] (J. Bucanek), Jun87, 122
subroutines
arithmetic, integer, incl. square root, in "Solid Shape Drawing on the Commodore 64" (R. Rylander), May85, 50
division [16-bit by 8-bit], improvement of a Leventhal routine (W.D. Maurer), Mar82, 20
graphics, in "Solid Shape Drawing on the Commodore 64" (R. Rylander), May85, 50
Cheers
Ed
Edit: added some links.
Edit: two more links, thanks Mike!
