Intel 4004(redirected from Microprocessor 4004)
The world's first microprocessor, released in 1971. The 4004 contained 2300 transistors (compared with 5.5 million in the 1996 Pentium Pro) and was intended for use in a calculator. It processed data in 4 bits, but its instructions were 8 bits long. Program and Data memory were separate, it had 1 kilobyte of data memory and a 12-bit PC for 4K of program memory (in the form of a 4 level stack, used for CALL and RET instructions). There were also sixteen 4-bit (or eight 8-bit) general purpose registers. The 4004 had 46 instructions.