What is Z80 assembly?
Z80 Assembly is an assembly language for the Zilog Z80 processor, which was introduced in 1976 and used in 1980s home computers such as the Sinclair ZX Spectrum and the Amstrad CPC series. Today, the Z80 is still widely used in embedded systems and consumer electronics.
What are the functions of the index registers in a Z80?
Index Registers (IX and IY) The Z80 has two 16-bit registers called index registers that are used to store 16-bit addresses. These registers are used to identify locations for data transfer. Stack Pointer (SP) This is also a 16-bit register that is used to point to the memory location called the stack.
How does a Z80 work?
The Z80 uses a 16-bit program counter (PC) to hold the memory address of the next instruction to execute. This register gradually steps through memory as instructions are executed, but some instructions can alter it directly to cause the flow of the program to branch to a new location.
How many locations can the Z80 CPU address?
The Z80 microprocessor is an 8-bit CPU with a 16-bit address bus capable of direct accessing 64k of memory space. The Z80 CPU can execute 158 different instructions. The Z80 CPU contains 208 bits of R/W memory that are available to the programmer.
How many gates are there in Z80?
Since there are 8 gates in total – one for each data bit – they can be thought of as another full 8-bit register sitting on the data bus.
What is a Z80 note?
The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company’s first product. The Zilog Z80 is a software-compatible extension and enhancement of the Intel 8080 and, like it, was mainly aimed at embedded systems.
What used the Z80?
The Zilog Z80 is a software-compatible extension and enhancement of the Intel 8080 and, like it, was mainly aimed at embedded systems. Although used in that role, the Z80 also became one of the most widely used CPUs in desktop computers and home computers from the 1970s to the mid-1980s.
How many instructions does a Z80 have?
This scheme gives the Z80 a large number of permutations of instructions and registers; Zilog categorizes these into 158 different “instruction types”, 78 of which are the same as those of the Intel 8080 (allowing operation of all 8080 programs on a Z80).
How many transistors are in a Z80?
Microprocessors
| Processor | MOS transistor count | Designer |
|---|---|---|
| Zilog Z80 (8-bit, 4-bit ALU, 40-pin) | 8,500 | Zilog |
| Intel 8085 (8-bit, 40-pin) | 6,500 | Intel |
| TMS9900 (16-bit) | 8,000 | Texas Instruments |
| Bellmac-8 (8-bit) | 7,000 | Bell Labs |
How many instructions does the Z80 have?
158
This scheme gives the Z80 a large number of permutations of instructions and registers; Zilog categorizes these into 158 different “instruction types”, 78 of which are the same as those of the Intel 8080 (allowing operation of all 8080 programs on a Z80).
Is Z80 still manufactured?
It’s still popular enough that Littelfuse/IXYS/Zilog still produces and develops the Z80 family. The new ones get internal Ethernet hardware and TCP/IP stack and run at 50MHz, too. Z80 is somewhat obsolete.
Is Z80 still used?
Z80s are still used even today, where a high-power processor isn’t needed. Many Texas Instruments graphing calculators still use Z80 processors today, as well as many other low-cost devices that need a little processing power.
What are the registers in a Z80 microprocessor?
Z80 microprocessor has the following registers: Accumulator (A) register is an 8-bit register used for arithmetic, logic, I/O and load/store operations. Flag is an 8-bit register containing 6 1-bit flags:
How are flags treated in the Z80 microprocessor?
In a few instructions the flags are treated as a single byte that is called the F register. The Z80 contains two types of 16-bit addressing registers: register pairs and index registers. Register pairs are formed from combinations of the 8-bit general purpose registers.
What is the memory address of the Z80?
These 8-bit registers can also be combined in pairs to form 16-bit addresses and these addresses can be used to index data structures in memory that span several bytes. The Z80 uses a 16-bit program counter (PC) to hold the memory address of the next instruction to execute.
How is HL register used in Zilog Z80?
The HL register can be used for register indirect addressing. The Z80 CPU includes alternative set of of Accumulator, Flag and General registers. It is not possible to change those registers directly, but it’s possible to swap main and alternative registers thus getting access to alternative registers.
