640 x 480 2-4 Color VGA Bitmap Driver

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By: Kwabena W. Agyeman, created: 2009-11-01 | updated: 2013-06-17

 

A 640 x 480 2-4 Color VGA bitmap driver that runs on one cog. The code has been fully optimized with a super simple spin interface for maximum speed and is also fully commented.
 
Provides full support for:
  • Plotting characters in spin, in both 2 and 4 color mode.
  • Plotting pixels in spin, in both 2 and 4 color mode.
 
The horizontal resolution may be any value that satisfies these rules:
  • The value is between 1 and 640.
  • The value is a factor of 640.
  • The value is divisible by 16 if in 1 color mode.
  • The value is divisible by 32 if in 2 color mode.
 
The vertical resolution may be any value that satisfies these rules:
  • The value is between 1 and 480.
  • The value is a factor of 480.
 
In two color mode the driver needs a display buffer in longs that is ((horizontalResolution * verticalResolution) / 32). The entire screen may have only two colors. Those two colors may be choosen from a 64 color palette.
 
In four color mode the driver needs a display buffer in longs that is ((horizontalResolution * verticalResolution) / 16). The entire screen may have only four colors. Those four colors may be choosen from a 64 color palette.
 
This list of features is not comprehensive. Please download the source code and run the included demo to gain a better understanding of this driver.
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Package icon VGA64_BMPDemo.zip8.08 KB