8080

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8080, a 8-bit microprocessor from Intel released in April 1974 running at 2 MHz. The 8080 is generally considered to be the first truly usable microprocessor. It had an 8-bit data-bus and 16-bit address-bus, allowing to address 64 KByte of memory, containing program code as well as data (Von Neumann architecture).

=Architecture= Intel 8080 Architecture

=Register Files= 8080 had seven byte-registers: A, B, C, D, E, H, and L. A was the 8-bit accumulator for most arithmetical and logical instructions and the other six could be used as either byte-registers or as three 16-bit register pairs (BC, DE, HL) depending on the particular instruction. HL was also used as (a limited) 16-bit accumulator. It further had a 16-bit stack pointer register and an 16-bit instruction pointer. After a hardware reset ip was cleared zero and started to fetch the first instruction from that address.

=Successors= Successor was Intel 8085 in 1977 with same instruction set but required less supporting hardware, and Zilog Z80.

=Endianess= 8080 and all it's successors were little-endian machines, concerning the byte-order of 16-bit words in memory.

=Software=

Operating Systems

 * CP/M from Wikipedia
 * ISIS (operating system) from Wikipedia

Development

 * ASM 80
 * C
 * PL/M
 * Turbo Pascal

Chess Programs

 * 8080 Chess
 * MicroChess

=See also=
 * 6502
 * 6800
 * SMS 201
 * Z80

=Publications=
 * Tandy/Radio Shack (1977). 8080-8085 Assembly Language Programming (Intel). |Internet Archive
 * Kathe Spracklen (1979). Z-80 and 8080 assembly language programming. Hayden Books, amazon.com, Internet Archive

=Forum Posts=
 * Computing from the Old Days, brought back to life by Steven Edwards, CCC, August 16, 2012

=External Links=
 * Intel 8080 from Wikipedia
 * KR580VM80A from Wikipedia
 * Intel 8085 from Wikipedia


 * 8080 Instruction Set - Computer Science Now
 * 8080/Z80 Instruction Set
 * Intel 8080 emulator by Óscar Toledo Gutiérrez

=References=

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