allbery@ncoast.UUCP (01/01/70)
As quoted from <16456@toto.uucp> by dbercel@toto.uucp (Danielle Bercel, MIS Systems Programming): +--------------- | The Intel 4004 was followed by the 8008 and then the 8080. Zilog | followed with the Z80 and Motorola came up with the 6500 (01?). | After that, the industry began forming along the lines we are | familar with today. +--------------- Actually, Motorola developed the 6800 microprocessor; then some of the Motorola 6800 design team split away and formed MOS Technology, then developed the 6502. The two are quite similar, the major difference being that, while both had 3 8-bit registers, the 6800 had two accumulators and an index register (A, B, and X registers) while the 6502 had one accumulator and two index registers (A, X, and Y registers). BTW, if there are any 6502 mavens out there (comp.sys.apple?): did anyone ever find a use for the Y-indirect addressing mode? (There are two indirect addressing modes on the 6502: (X)+nnn (called XI) and (Y+nnn) (called IY). IY addressing almost looks like a primitive page addressing scheme... [I may have the two modes reversed in various ways; been a few years since I was an OSI C1P hacker... but I rememver always using the one that indexed after the indirection, as it was perfect for table lookups via pointers, while there were few times indeed where I wanted to index before the indirection.] -- Brandon S. Allbery, moderator of comp.sources.misc and comp.binaries.ibm.pc {{harvard,mit-eddie}!necntc,well!hoptoad,sun!mandrill!hal}!ncoast!allbery ARPA: necntc!ncoast!allbery@harvard.harvard.edu Fido: 157/502 MCI: BALLBERY <<ncoast Public Access UNIX: +1 216 781 6201 24hrs. 300/1200/2400 baud>> ** Site "cwruecmp" is changing its name to "mandrill". Please re-address ** *** all mail to ncoast to pass through "mandrill" instead of "cwruecmp". ***