The Intel 8080 was the first popular 8-bit microprocessor CPU. It was the successor to the 8008, which was the very first 8-bit microprocessor. It was succeeded by the 8085, and then by 16-bit processors. The Zilog Z-80 had the 8080 instruction set as a subset of its own instruction set.
The chip supported hardware interrupts, 256 I/O ports, 64 Kb of memory, BCD and integer add/subtract, call/return, branching, logic operations, and shift/rotate.
Data size = 8 bits
Address size = 16 bits
8-bit Registers: A, B, C, D, E, H, L
16-bit Registers: PC, SP
Six of the 8-bit registers could be used as 3 16-bit registers: BC, DE, HL. The HL pair was used for memory-indirect access. A (the accumulator) was the only register that supported arithmetic operations.
Instruction set: ADD, ADC, ADI, ANA, ANI, CALL, CNZ, CZ, CNC, CC, CPO, CPE, CP, CM, CPI, CMA, CMC, CMP, DCR, DCX, DAD, DAA, DI, EI, HLT, IN, INR, INX, JMP, JNZ, JZ, JNC, JC, JPO, JPE, JP, JM, LXI, LDAX, LHLD, LDA, MOV, MVI, NOP, OUT, ORA, ORI, PCHL, POP, PUSH, RET, RNZ, RZ, RNC, RC, RPO, RPE, RP, RM, RST, RLC, RRC, RAL, RAR, SBI, SUI, SHLD, STA, STAX, SPHL, STC, SBB, SUB, XRA, XRI, XTHL, XCHG.