We believe in the long term value of Apple hardware. You should be able to use your Apple gear as long as it helps you remain productive and meets your needs, upgrading only as necessary. We want to help maximize the life of your Apple gear. The used 6 micron traces. The Zilog Zdesigned by former Intel employees, was essentially an clone with 80 additional instructions. It came out in July The Z ran at speeds from 2. Intel also introduced a slightly improved version of thethe While 8-bit processors seemed impressive in the late s, by the early s it was becoming evident that their days were numbered as far as personal computers went.

Newer CPUs with bit designs were able to address vastly increased amounts of memory, something made necessary by large spreadsheets, large word processing documents, and large databases. These CPUs have lives on in arcade machines, gaming consoles, and scientific calculators, as well as credit card terminals, sequencers, and synthesizers.

Next: Intel and Low End Mac is funded primarily through donations. All of our advertising is handled by BackBeat Media. For price quotes and advertising information, please contact BackBeat Media at This number is for advertising only. Welcome Image and Text. Like this: Like Loading Donations Donations Low End Mac is funded primarily through donations. Join our email lists! Sorry, your blog cannot share posts by email.The Intel "eighty-eighty" is the second 8-bit microprocessor designed and manufactured by Intel.

It first appeared in April and is an extended and enhanced variant of the earlier design, although without binary compatibility. A faster variant A-1 Sometimes called the B became available later with clock frequency limit up to 3. Although earlier microprocessors were used for calculatorscash registerscomputer terminalsindustrial robots[5] and other applications, the became one of the first widespread microprocessors.

The was successful enough that translation compatibility at the assembly language level became a design requirement for the Intel when its design began inand led to the directly influencing all later variants of the ubiquitous bit and bit x86 architectures. The Intel is the successor to the It uses the same basic instruction set and register model as the developed by Computer Terminal Corporationeven though it is not source code compatible nor binary code compatible with its predecessor.

Every instruction in the has an equivalent instruction in the even though the opcodes differ between the two CPUs. The also adds a few bit operations in its instruction set. Whereas the required the use of the HL register pair to indirectly access its bit memory space, the added addressing modes to allow direct access to its full bit memory space.

In addition, the internal 7-level push-down call stack of the was replaced by a dedicated bit stack-pointer SP register. The processor has seven 8-bit registers A, B, C, D, E, H, and Lwhere A is the primary 8-bit accumulator, and the other six registers can be used as either individual 8-bit registers or as three bit register pairs BC, DE, and HL, referred to as B, D and H in Intel documents depending on the particular instruction.

Some instructions also enable the HL register pair to be used as a limited bit accumulator, and a pseudo-register M can be used almost anywhere that any other register can be used, referring to the memory address pointed to by the HL pair. It also has a bit stack pointer to memory replacing the 's internal stackand a bit program counter. The processor maintains internal flag bits a status registerwhich indicate the results of arithmetic and logical instructions.

Only certain instructions affect the flags.

Lecture 3: Overflow flag for signed addition and subtraction

The flags are:. The carry bit can be set or complemented by specific instructions. Conditional-branch instructions test the various flag status bits. The flags can be copied as a group to the accumulator. The A accumulator and the flags together are called the PSW register, or program status word. As with many other 8-bit processors, all instructions are encoded in one byte including register numbers, but excluding immediate datafor simplicity.

Some of them are followed by one or two bytes of data, which can be an immediate operand, a memory address, or a port number. Like larger processors, it has automatic CALL and RET instructions for multi-level procedure calls and returns which can even be conditionally executed, like jumps and instructions to save and restore any bit register pair on the machine stack. There are also eight one-byte call instructions RST for subroutines located at the fixed addresses 00h, 08h, 10h, These were intended to be supplied by external hardware in order to invoke a corresponding interrupt service routinebut were also often employed as fast system calls.

The most sophisticated command is XTHLwhich is used for exchanging the register pair HL with the value stored at the address indicated by the stack pointer. Most 8-bit operations can only be performed on the 8-bit accumulator the A register.The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company 's first product.

The Z80 was conceived by Federico Faggin in late and developed by him and his 11 employees starting in early The first working samples were delivered in Marchand it was officially introduced on the market in July With the revenue from the Z80, the company built its own chip factories and grew to over a thousand employees over the following two years. The Zilog Z80 is a software-compatible extension and enhancement of the Intel 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 s to the mids.

The design was also copied by several Japanese, East European and Soviet manufacturers. At Fairchild Semiconductorand later at IntelFaggin had been working on fundamental transistor and semiconductor manufacturing technology. He also developed the basic design methodology used for memories and microprocessors at Intel and led the work on the Intelthe and several other ICs. Masatoshi Shimathe principal logic and transistor level-designer of the and the under Faggin's supervision, joined the Zilog team.

According to the designers, the primary targets for the Z80 CPU and its optional support and peripheral ICs [ii] were products like intelligent terminalshigh end printers and advanced cash registers as well as telecom equipment, industrial robots and other kinds of automation equipment.

By MarchZilog had developed the Z80 as well as an accompanying assembler based development system for its customers, and by Julythis was formally launched onto the market. Early Z80s were manufactured by Synertek and Mostekbefore Zilog had its own manufacturing factory ready, in late These companies were chosen because they could do the ion implantation needed to create the depletion-mode MOSFETs that the Z80 design used as load transistors in order to cope with a single 5 Volt power supply.

Masatoshi Shima designed most of the microarchitecture as well as the gate and transistor levels of the Z80 CPU, assisted by a small number of engineers and layout people. According to Faggin, he worked 80 hours a week in order to meet the tight schedule given by the financial investors. The Z80 offered many improvements over the [7].

The Z80 took over from the and its offspring, thein the processor market, [15] and became one of the most popular 8-bit CPUs. Some organisations, such as BTremained loyal to the for embedded applications owing to their familiarity with it, and to its on-chip support for a serial interface and multi-level interrupt architecture.

Perhaps a key to the initial success of the Z80 was the built-in DRAM refresh, and other features which allowed systems to be built with fewer support chips Z80 embedded systems typically use static RAM and hence do not need this refresh. For the original NMOS design, the specified upper clock frequency limit increased successively from the introductory 2.

Zilog Z80 vs Intel 8086 (overview)

The CMOS versions allowed low-power sleep with internal state retained, having no lower frequency limit. The programming model and register set of the Z80 are fairly conventional, ultimately based on the register structure of the Datapoint The Z80 was designed as an extension of thecreated by the same engineers, which in turn was an extension of the The also introduced the important 8-bit immediate data mode for accumulator operations, and immediate bit data for HL, BC and DE loads.

Furthermore, direct bit copying between HL and memory was now possible, using a direct address. The Z80 orthogonalized this further by making all bit register pairs, including IX and IY, more general purpose, as well as allowing bit copying directly to and from memory for all of these pairs.

The bit IX and IY registers in the Z80 are primarily intended as base address-registers, where a particular instruction supplies a constant offset that is added to the previous values, but they are also usable as bit accumulators, among other things. The Z80 also introduced a new signed overflow flag and complemented the fairly simple bit arithmetics of the with dedicated instructions for signed bit arithmetics.Why don't fictional characters say "goodbye" when they hang up a phone?

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Wiki User The difference between the and A microprocessor is that the A is a bug-fixed version of the A. The original was manufactured by Intel only before being quickly replaced with the A. All of these are very initial processors from Intel. Asked in Intel Microprocessors What is the Intel ? Intel is a microprocessor that is used in various electronics devices. Yes, the Intel is an 8 bit microprocessor.

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z80 vs 8086

What's new? Page 1 of 3 1 2 3 Last Jump to page: Results 1 to 10 of Thread: What's the difference between a processor and a Z80? Thread Tools Show Printable Version. What's the difference between a processor and a Z80?

Someone mentioned this on another forum, though I don't know a lot about thethough they were saying that an was more like an and perhaps more advanced than a Z What puzzles me is Computers and Games Machines were using Z80, and the early Nintendo Gameboys had an Z80 in it into the late 80s early 90s. Also I need some reminder about which was first between and I think came first, but was more powerful in the Data Bus than the later Unsure about this though.

The similarity is that they are both 8-bit MPUs. Hi, As mentioned, the was made by Intel, the Z80 by Zilog. The is a very close relative of the and off the top of my head the main difference was the addition of RIN and SIN but there may be others. The Z80 was like an with fewer power supply requirements, dynamic RAM refresh on-chip, an alternative set of registers and index registers. The Z80 instruction set is compatible with in that a Z80 will run code but not the other way round because of the other features.

Cheers, Andy. It was binary compatible with the more-famous Intel but required less supporting hardware, thus allowing simpler and less expensive microcomputer systems to be built. The is a conventional von Neumann design based on the Intel Unlike the it does not multiplex state signals onto the data bus, but the 8-bit data bus was instead multiplexed with the lower part of the bit address bus to limit the number of pins to Pin No. Pins No. Only a 5 Volt supply is needed, like competing processors and unlike the The uses approximately 6, transistors.

8080/Z80 Instruction Set

A downside compared to similar contemporary designs such as the Z80 was the fact that the buses required demultiplexing; however, address latches in the Intel, and memory chips allowed a direct interface, so an along with these chips was almost a complete system.

Perhaps a key to the initial success of the Z80 was the built-in DRAM refresh, and other features which allowed systems to be built with fewer support chips later on, most Z80 systems have been embedded systems, which typically uses static RAM and hence does not need this refresh.

I began developing for the around The particular product that I worked on used two one for the CPU and one to control the printer. The was well suited to embedded applications--it was simple to interface to and there were a few peripheral chips that could really cut parts count e.

The on-chip prioritized "half interrupts" made things even easier--no need for a dedicated interrupt controller. Because the really enjoyed its popularity in the embedded applications, it's easy to make the pronoucement that it wasn't a popular chip.

Nothing could be further from the truth--Intel and its licensees sold an ocean of the and 80C85s--it was a very profitable product line. One mistake that Intel made that still peeves me was the initial non-disclosure of the extra instructions that would have made life much more easy.

Thanks Guys. You should be aware that there's a chip from National, the NSC, that is sort of a hybrid between the Z80 and By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Retrocomputing Stack Exchange is a question and answer site for vintage-computer hobbyists interested in restoring, preserving, and using the classic computer and gaming systems of yesteryear.

It only takes a minute to sign up. The Zilog Z80 microprocessor, known for its use in the ZX Spectrum, was designed to be a backwards-compatible extension to the Intel processor. It introduced several new instructions to the 's instruction set, as well as adding or extending registers.

But, as those of us who've used undocumented opcodes know, you can never add without taking. Every change breaks someone's workflow program.

z80 vs 8086

So what are the differences between the instruction sets of these two "compatible" chips? For the most part the Z extends the instruction set. If we consider just the instructions themselves there are a few incompatibilities:. The ED series are a mixed set of extensions prominently featuring the block move instructions:. The Z does not have a new JP instruction that tests the overflow flag. This remains the conditional jump based on parity but the "parity" bit is set based on overflow for arithmetic instructions.

A good handful of the new Z instructions deal with new interrupt handling modes.

z80 vs 8086

If you're looking to port Z code to there is a relatively short list of things to watch out for:. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. How did the Z80 instruction set differ from the ? Ask Question. Asked 3 years, 5 months ago. Active 2 years, 9 months ago. Viewed 9k times. Irrelevant to the question but did you know that the Z80 is used in the Ti series calculators and the Nintendo Gameboy?

Thanks for that information! If you count the original processor, its clones and descendants, the Z80 was, and probably still is, the best-selling microprocessor in history. The year marks 40 years that the family has been in production. There is a third aspect which does not have an established name, which is about things like process node, cache size and other optional or configurable parts, Even relying on some invalid operation, happening as a side effect of some efficient way to do something intended, to fail can break someone's workflow if things unexpectedly succeed.

Active Oldest Votes. If we consider just the instructions themselves there are a few incompatibilities: Overflow flag. On the bit 2 of the flags register only reports the parity of the accumulator after an ALU operation.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Disadvantages of the 8088

Retrocomputing Stack Exchange is a question and answer site for vintage-computer hobbyists interested in restoring, preserving, and using the classic computer and gaming systems of yesteryear. It only takes a minute to sign up. Some assumptions were that bit must be more bloaty due to its need for an address mode byte in each instruction, whereas 8-bit includes this in the opcode, while others claimed code to be quite compact. While this reminds of the old CPU-wars, there must be some tradeoff, as the ROM sizes in some examples are quite close between x80 and x Code can often be optimized by narrowing down the environment.

The examples are meant rather for a generic estimation. The question has already been asked in ways of vs. Z80 and PNDC provided a good answer pointing out that real code can always be seen as a form of variable length encoding preferring shorter codes for more often used instructions. He as well cites a quite nice paper about Code Density Concerns. Here various architectures, including Z80 and are treated in assembly to solve certain problems.

So 16 bit seems like a clear winner in code size. Except, it somehow feels wrong, doesn't it? So maybe some explicit example? One simple way to do is to see if bytes can be changed at will. There may be many machine specific ways to do so, this is a simple generic, checking every first byte of a byte page of it can be written.

The same, translated for And yes, the example is picked on purpose, as 8 of the 12 instructions are single byte on the side, which usually result in the worst case result of doubling code size. So already a straight translation without using any new feature or optimization produces acceptable results. Now lets take something else, maybe were the x86 can use some of its advantage.


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