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hardware:custom_chipset [2010/03/07 09:50]
gilgamesh more on copper 		hardware:custom_chipset [2010/03/09 09:30]
gilgamesh screen widths
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 ====== Custom Chipset ====== ====== Custom Chipset ======
-The chipset is responsible for the Amiga's ground breaking multimedia capabilities. It consists of several chips that take load off the main CPU perform various tasks. There are three generations of chipsets are found in classic Amigas: OCS, ECS and AGA.+The chipset is responsible for the Amiga's ground breaking multimedia capabilities. It consists of several chips that take load off the main CPU by performing various tasks. There are three generations of chipsets are found in classic Amigas: OCS, ECS and AGA.
  
 ===== OCS ===== ===== OCS =====
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 === Blitter === === Blitter ===
-The Blitter is co-processor logic that copies memory areas from one place to another in the chipmem asynchronosly.+The Blitter is co-processor logic that copies memory areas from one place to another in the chipmem asynchronosly by DMA. Blitter draws (patterned) lines and fills their interior or exterior, too. Blitter operations are called [[hardware/blitter programming model|blits]].  
 + 
 +The Blitter operates on data words. It can perform bytewise and bitwise shifts. Up to three source blocks can be processed in a boolean logic function and the result is written to the destination block.  
 +Rectangular //m,n//-blocks are stored in //m • n// consecutive memory cells. It is easy to see how entire block are shifted. But subrectangles are shifted, by supplying its index (in bytes), the length (in words) and the gap between two lines called //modulo// (in bytes).
  
 === Copper === === Copper ===
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 The bitfields and palette information combined produce the so called playfield, a rectangular area of pixels. Playfields can actually be larger than the nominal display size (PAL, NTSC; LoRes, HiRes) to allow smooth scrolling of backgrounds. The bitfields and palette information combined produce the so called playfield, a rectangular area of pixels. Playfields can actually be larger than the nominal display size (PAL, NTSC; LoRes, HiRes) to allow smooth scrolling of backgrounds.
 +
 +The display size is
 +^  Resolution  ^  Columns  ^ ^  Norm  ^  Interlaced  ^  Lines  ^ 
 +|  LoRes  |  320  | :::|  PAL  |  no  |  256  | 
 +|  :::  |  :::  | :::|  :::  |  yes  |  512  | 
 +|  HiRes  |  640  | :::|  NTSC  |  no  |  200  | 
 +|  :::  |  :::  |::: |  :::  |  yes  |  400  | 
  
 ==== Paula ==== ==== Paula ====
hardware/custom_chipset.txt · Last modified: 2010/03/09 10:01 by gilgamesh
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