Tag Archives: retro

In Praise Of Zilog’s Z80 Microprocessor

zilog,Zilog,ZILOG,z,Z,z80,Z80,z 80,Z 80,z-80,Z-80,80,80s,80's,80S,80'S,eighties,Eighties,EIGHTIES,z80A,Z80A,z80B,Z80B,cpu,Cpu,CPU,micro,Micro,MICRO,processor,Processor,PROCESSOR,computer,Computer,COMPUTER,msx,Msx,MSX,2,2+,turboR,turbo R,turbo r,turbo,Turbo,TURBO,records,Records,RECORDS,intel,Intel,INTEL,8080,arm,Arm,ARM,risc,Risc,RISC,cisc,Cisc,CISC,sharp,Sharp,SHARP,X1,X1 twin,X1 turbo Z,sinclair,Sinclair,SINCLAIR,zx,Zx,ZX,80,81,spectrum,Spectrum,SPECTRUM,48,128,+,+1,+2,+3,48K,128K,ram,Ram,RAM,rom,Rom,ROM,accumulator,Accumulator,ACCUMULATOR,register,Register,REGISTERS,zeus,Zeus,ZEUS,zaus,Zaus,ZAUS,assembly,Assembly,ASSEMBLY,assembler,Assembler,ASSEMBLER,.asm,.Asm,.ASM,machine,Machine,MACHINE,code,Code,CODE,mos,Mos,MOS,6502,8502,commodore,Commodore,COMMODORE,radio,Radio,RADIO,shack,Shack,SHACK,tandy,Tandy,TANDY,trs-80,Trs-80,TRS-80,trs 80,Trs 80,TRS 80,snk,Snk,SNK,triple,Triple,TRIPLE,arcade,Arcade,ARCADE,arcades,Arcades,ARCADES,board,Board,BOARD,boards,Boards,BOARDS,motherboard,Motherboard,MOTHERBOARD,sega,Sega,SEGA,sg-1000,SG-1000,sc 3000,SC 3000,SC-3000,game,Game,GAME,games,Games,GAMES,gear,Gear,GEAR,gears,Gears,GEARS,nec,Nec,NEC,pc,Pc,PC,PC-6000,PC-6001,PC6601,PC-8000,PC-8001,amstrad,Amstrad,AMSTRAD,cpc,Cpc,CPC,464,664,6128,464plus,6128plus,plus,Plus,PLUS,8bit,8-bit,8 bit,8BIT,8-BIT,8 BIT,16bit,16 bit,16-bit,16BIT,16-BIT,16 BIT,mega,Mega,MEGA,drive,Drive,DRIVE,master,Master,MASTER,system,System,SYSTEM,coleco,Coleco,COLECO,vision,Vision,VISION,ColecoVision,colecovision,Colecovision,COLECOVISION,nintendo,Nintendo,NINTENDO,gameboy,Gameboy,GAMEBOY,boy,Boy,BOY,color,Color,COLOR,pocket,Pocket,POCKET,neo,Neo,NEO,geo,Geo,GEO,neo geo,Neo Geo,NEO GEO,neogeo,Neogeo,NeoGeo,NEOGEO,playmore,Playmore,PLAYMORE, — The choice of the 8-bit generation!

Video games are an electronic medium and quite naturally require some form of computer hardware to run on. The CPU (central processing unit or processor if you prefer) has always played a vital part in the creation and execution of game code. Without this important component, video games would simply not exist. After all the processor is essentially the brain of a computer system…basic stuff!

And just as human brains can vary in intellectual capacity, various makes and models of microprocessors offer different performance capabilities. For game related tasks, the GPU (graphics processing unit) plays an even greater role within the modern game development paradigm. However, this article is not about development techniques and how they are to be applied to modern hardware. Rather, we will look at a specific microprocessor which played a leading role in defining gaming during it’s early stages.

Two prominent periods of gaming are the 8-bit and 16-bit eras, and quite frankly of greatest import. As shiny as our games are, and powerful as our hardware is nowadays – none of this would exist without the groundwork laid down during those halcyon days. And both those eras brought forward to amazing microprocessors that truly revolutionized gaming, namely the Zilog Z80 and the Motorola 68000.

Zilog’s Z80 truly helped to kick start affordable home computing and arcade gaming from the late 70’s onward. The Z80 is an 8-bit processor, which is closely based on Intel’s earlier 8080 CPU. Due to it’s performance and versatility, it was adopted by a large variety of computer and arcade amusement vendors. Either Zilog’s original CPU, clones or variants of the Z80 architecture was incorporated into motherboards worldwide. Everyone from Sinclair Research right through to Sega made use of this mighty little chip, benefiting gaming inexplicably.

Some will argue in favour of a rival 8-bit microprocessor, namely the 6502 by MOS Technology. Also very popular and widely used, particularly in the home computer market but also made in-roads in the arcades thanks to Atari. However, the true acid test of which 8-bit processor was better, rests with the greater adoption enjoyed by the Z80, especially among Japanese arcade manufacturers. From Namco’s Galaxian through to Irem’s M52 system boards, the Z80 was the CPU of choice.

None can downplay the wide adoption of the Z80 when considering it brain-powered the following systems:

Sinclair ZX80 & ZX81
Sinclair ZX Spectrum 16K / 48K / + / 128K / +2 / +3
Amstrad / Schneider CPC464 / 464plus / CPC664 / CPC6128 / 6128plus
Amstrad GX4000
Cambridge Z88
SAM Coupé
Tandy / Radio Shack TRS-80 series
Coleco’s – ColecoVision
Commodore 128 (includes both a Zilog Z80A & MOS 8602)
NEC PC-6001 / mkII / mkIISR (using NEC’s μPD780C – a Z80 compatible CPU)
NEC PC-6601
NEC PC-8000 series
NEC PC-8801 (a wide range of models manufactured between 1981 – 1989)
MSX 2 / 2+ / turboR
Sharp MZ-80K series / MZ-80B series / MZ-3500 series
Sharp X1 / X1 turbo / X1 turbo Z / X1 twin
Sony SMC-70
Sega SG-1000 / SG-1000 II / SC-3000 / Mark III / Master System
Sega Game Gear
Sega Mega Drive / Genesis (includes both a Motorola 68000 & Zilog Z80)
SNK Neo Geo (includes both a Motorola 68000 & Zilog Z80)
SNK Neo Geo Pocket / Color (includes both a TOSHIBA TLCS-900H & Z80)
Nintendo Game Boy / Color (Sharp LR35902 – a custom Z80 CPU)

The above list is only a small segment of computer and console systems that the trusty Z80 found itself in. Arcade manufacturers in particular, truly took advantage of this versatile processor in numerous ways. Initially arcade boards would only be designed with a singular Z80 CPU in place. But as games were becoming more complex, some added processing grunt was required. Since the Z80 was affordable and developers already accustomed to coding games for it, a very common solution was to add a secondary Z80 to increase the board’s horsepower.

SNK (Shin Nihon Kikaku Corporation) were always partial to manufacturing some fantastically exotic boards. During the mid-80’s they came up with the SNK Triple Z80 arcade board, and as the name suggests – boasts three Zilog Z80’s working in tandem. Two Z80’s were allocated to handle main CPU duties, while the third was specifically for sound CPU tasks. The games that ran on this board naturally surpassed the audio and visual fidelity of many of it’s counterparts. Resulting in games that had a look, feel and sound closer to the 16-bit standard.

My personal experiences with the Z80 were both positive and enjoyable, owning a ZX Spectrum played a big part in this. I learned to program on it, firstly in BASIC and then later on in machine code – wasn’t easy but I got the nitty-gritty. Later on I got hold of Zeus Assembler which made programming in assembly far more palatable to machine code.

Generally it didn’t take long to get accustomed to how the accumulator and various registers within the Z80 work together. The architecture is simple and elegant enough, not hard to figure out why it was so readily adopted. Not bad for a microprocessor that was originally intended for cash registers, instead of computers, consoles and arcade machines.

80’s Sci-Fi Inspiration – Brazil

brazil,Brazil,BRAZIL,the,The,THE,movie,Movie,MOVIE,film,Film,FILM,terry,Terry,TERRY,gilliam,Gilliam,GILLIAM,eighties,Eighties,EIGHTIES,sci,Sci,SCI,-,fi,Fi,FI,80s,80 s,80,80's,uk,Uk,UK,british,British,BRITISH,robert,Robert,ROBERT,de,DE,De,niro,Niro,NIRO,jonathan,Jonathan,JONATHAN,pryce,Pryce,PRYCE,retro,Retro,RETRO,ware,Ware,WARE,wave,Wave,WAVE,new,New,NEW,art,Art,ART,house,House,HOUSE,experimental,Experimental,EXPERIMENTAL,weird,Weird,WEIRD,edgy,Edgy,EDGY,edge,Edge,EDGE,illusion,Illusion,ILLUSION,city,City,CITY,gnostic,Gnostic,GNOSTIC,gnosticism,Gnosticism,GNOSTICISM,cyber,Cyber,CYBER,punk,Punk,PUNK,police,Police,POLICE,state,State,STATE,dystopia,Dystopia,DYSTOPIA,dystopian,Dystopian,DYSTOPIAN,fantasy,Fantasy,FANTASY,funny,Funny,FUNNY,fun,Fun,FUN,magic,Magic,MAGIC,future,Future,FUTURE,futuristic,Futuristic,FUTURISTIC,gaia,Gaia,GAIA,explosion,Explosion,EXPLOSION,explosions,Explosions,EXPLOSIONS,explosive,Explosive,EXPLOSIVE,satire,Satire,SATIRE,satirical,Satirical,SATIRICAL,computer,Computer,COMPUTER,computers,Computers,COMPUTERS,komputer,Komputer,KOMPUTER,komputers,Komputers,KOMPUTERS,legend,Legend,LEGEND,legendary,Legendary,LEGENDARY,axe,Axe,AXE,golden,Golden,GOLDEN,jaleco,Jaleco,JALECO,samurai,Samurai,SAMURAI,ghost,Ghost,GHOST,indie,Indie,INDIE,game,Game,GAME,dev,Dev,DEV,ninja,Ninja,NINJA,kun,Kun,KUN,south,South,SOUTH,america,America,AMERICA,africa,Africa,AFRICA,cult,Cult,CULT,classic,Classic,CLASSIC,arcade,Arcade,ARCADE,arcades,Arcades,ARCADES — This has to be one of the coolest movie posters of all time

Over the weekend I decided to indulge in a little art house & old school movie viewing. Working in a creative medium such as games, it’s always a good idea to draw inspiration from various outside sources. It’s no secret that games, from their very inception were influenced by the film, animation and comic book mediums, considerably.

I’ve always been a fan of the science fiction genre, my interest started when I picked up an issue of 2000 AD (loved the Judge Dredd universe) and following the G-Force (also known as Gatchaman or Battle of the Planets) tv animation series. The 80’s in particular were a great time for the genre, an unprecedented number of excellent sci-fi movies were produced. So many, in fact, that it was difficult to keep up. One particular movie that I heard good things about but never got round to seeing is – Brazil.

Finally I managed something of a double bill, watching Brazil alongside Holy Motors. Both films were predictably unhinged, Holy Motors takes the cake – gorging on it and then spewing it out. Truth be said, I had high hopes for Holy Motors but it didn’t quite live up to the hype in my opinion. Certainly no sci-fi flick here, however treading experimental art movie territory closely. Seemingly a French Mulholland Drive of sorts, but with an entirely different message.

Brazil is a completely different beast altogether, definitely the better of the two movies by a significant margin. Directed by Terry Gilliam and starring Jonathan Pryce and Robert De Niro in this 1984-inspired dystopian cult-classic. Irreverent with a healthy dose of slapstick and satire goes some way to dilute the bureaucratic retro-futurist world depicted. Ironically, many countries in the present day seem to closely resemble this world, just without the aesthetic and humour.

There is also a healthy dose of the fantastical and exploration of the high-concept. The idea of an artificial simulated world as depicted in the Matrix films is not unique. Even Megazone 23, a Japanese anime produced by AIC in the mid-80’s covered similar ground. An excellent three part OVA that I should make a point of covering in a future article. While the use of this concept makes for some incredibly interesting sci-fi, it’s a concept that is sourced from certain religious spheres. Namely from the Ancient Gnostics and to a certain extent eastern esotericism including Buddhism.

Surely a movie such as Brazil would have shocked audiences with the issues it was exploring back in 1985. Watching it for the first time, 30 years later there just isn’t much shock value left. But this doesn’t diminish the film in any way, shape or form. For one, it’s delightfully unique while conveying a warning about bureaucracy and the police state.

Brazil certainly has the hallmarks of a top-notch cinematic experience, however it wouldn’t translate well as a game. At least, I’m not aware of there ever being a game conversion of this particular film license. Quite frankly, that’s a good thing as Brazil is so incredibly nuanced, it’s beyond the scope of the majority of game developers to reinterpret successfully.

Nevertheless, what I got out of Brazil was further affirmation of taking creative risks. There’s much in this movie that is off-kilter but in the grand scheme of things – everything works out!

Agent Smith Receives The 16-BIT Shock Treatment

Recently a fellow on twitter known as Dodekatheoi (we’re following each other) requested a pixel-art icon from me for his various social media and gaming accounts. In particular he wanted those icons to represent the infamous antagonist of the Matrix trilogy – Agent Smith. He also required that these icons be at screen dimensions of 100 x 100 and later on at 400 x 400. An intriguing prospect to say the least, which I was happy to dive into.

The Matrix movies are fairly stark visually, this works particulalry well in context. Everyone should have an idea of what these movies are about with their rather pessimistic, cyberpunk flavour. Mostly monotone colour hues are used throughout the trilogy, painting a grim alternate reality. Fortunately, pixel-art with it’s reliance on limited colour palettes is a perfect fit for such renditions in low-rez. Capturing the very essence of what Agent Smith is about would be a key goal. I, therefore opted to work directly from a still image from the movie which perfectly depicted this.

pixel,Pixel,PIXEL,art,Art,ART,agent,Agent,AGENT,smith,Smith,SMITH,the,The,THE,matrix,Matrix,MATRIX,cyber,Cyber,CYBER,punk,Punk,PUNK,90,90s,90's,'99,99,1999,neo,Neo,NEO,red,Red,RED,blue,Blue,BLUE,pill,Pill,PILL,science,Science,SCIENCE,fiction,Fiction,FICTION,movie,Movie,MOVIE,movies,Movies,MOVIES,16-BIT,Shock,SHOCK,shock,demos,Demos,DEMOS,antypas,Antypas,ANTYPAS,artist,Artist,ARTIST,game,Game,GAME,dev,Dev,DEV,developer,Developer,DEVELOPER,edit,Edit,EDIT,indie,Indie,INDIE,1bit,1-bit,1 bit,1Bit,1BIT,1-BIT,1 BIT,wacom,Wacom,WACOM,Intuos,intuos,INTUOS,digital,Digital,DIGITAL,palette,Palette,PALETTE,color,Color,COLOR,colors,Colors,COLORS,colour,Colour,COLOUR,colours,Colours,COLOURS,retro,Retro,RETRO,gaming,Gaming,GAMING, — Agent Smith as originally depicted in video form (left) to a pixel art icon (right)

At first glance, it would seem that by merely dithering the image the desired result would be produced. However, this is not the case as dithering such a low-quality image only produces a terrible, uneven pixel texture. Images like these, typically found with a google search and of standard definition video quality are overwrought with screen artifacts. At best, this image would only result in a cheap, dirty digitized look and not that of carefully crafted pixel art.

Nevertheless, the image was not completely useless – after all the depiction of Agent Smith was ideal. I decided to apply a hard contrast and then mask the image, giving me a good trace of the character. The mask was then layered in a new image to work on at a screen resolution of 100 x 100 pixels. After this I proceeded to clean up the image, getting rid of some nasty, rough edges and those odd pixels that were just at the wrong place.

Next came one of the most important steps in putting together a colour palette that would do the image justice. I decided to work in 8-bits per pixel from the get-go and narrowed the palette down to 12 colours. Initially when I started allocating colours and testing them out, I was already up to 20 colours but quickly ascertained that that’s too much. I gradually got rid of the unneccessary colours, keeping only those that worked best with the others within the palette.

I always keep a Wacom Intuos tablet handy for drawing purposes even though I’m proficient with a mouse. For pixel-art I feel the mouse is often the better choice but there are certain aspects that a pen and tablet handle better. In respect, to drawing organic imagery a pen and tablet beats out the mouse more often than not. Ditto for shading purposes, I’ve found there is a greater speed advantage with the Intuos. And in the case of the Agent Smith icon, the tablet came in as an indispensible tool.

The process from here on was a matter of working on those dots diligently, for a small image size such as this I seldom use more than 3 layers. Once the image looks satisfactory, it’s time for some minor colour balancing. Finally the image is complete and we have ourselves a nice rendition of Agent Smith with only 12 colours. I decided to further reduce the colour down to 8 colours on a secondary image and then down to 1-bit colour depth which comprises of only 2 colours.

Generally the process as a whole is not terribly complex, nor is it the only way to go about doing this. But I believe this one of the more efficient methods for pixel pushers. In my next pixel art article I will reveal some similar work I’ve done on Raiden, the main protagonist from Metal Gear Rising: Revengeance.