Video (PC8801): Difference between revisions

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(Background/foreground component toggle)
mNo edit summary
Line 31: Line 31:
|Toggle Background/Foreground color components
|Toggle Background/Foreground color components
|Toggles background and foreground color components on and off
|Toggles background and foreground color components on and off
if 8-color mode {
if 8-color mode {
  if bit 7 (mask 0x80) set, target is background color, else foreground
  if bit 7 (mask 0x80) set, target is background color, else foreground


  if bit 6 (mask 0x40) toggle green component {
  if bit 6 (mask 0x40) toggle green component {
    GREEN ON if bits 1,2,3 (0x7) set, else OFF
    GREEN ON if bits 1,2,3 (0x7) set, else OFF
  }
  }
  else toggle red and/or blue {
  else toggle red and/or blue {
    BLUE ON if bit 1,2,3 set, else OFF
    BLUE ON if bit 1,2,3 set, else OFF
    RED ON if value written / 8 sets bits 1,2,3, else OFF
    RED ON if value written / 8 sets bits 1,2,3, else OFF
  }
  }
}
}
else if monochrome mode, set foreground color {
else if monochrome mode, set foreground color {
  BLUE ON if bit 1 set (mask 0x1)
  BLUE ON if bit 1 set (mask 0x1)
  RED ON if bit 2 set (mask 0x2)
  RED ON if bit 2 set (mask 0x2)
  GREEN ON if bit 3 set (mask 0x4)
  GREEN ON if bit 3 set (mask 0x4)
}
}
|-
|-
|0x55-0x5b
|0x55-0x5b

Revision as of 22:17, 4 March 2016

Port Name Function
0x30
0x34
0x35
0x52 Background Color Sets the background color of the screen. The color is an RGB composite.

If bit 3 (mask 0x8) = blue on if bit 4 (mask 0x10) = green on If bit 5 (mask 0x20) = red on

0x53
0x54 Toggle Background/Foreground color components Toggles background and foreground color components on and off
if 8-color mode {
  if bit 7 (mask 0x80) set, target is background color, else foreground
  if bit 6 (mask 0x40) toggle green component {
    GREEN ON if bits 1,2,3 (0x7) set, else OFF
  }
  else toggle red and/or blue {
    BLUE ON if bit 1,2,3 set, else OFF
    RED ON if value written / 8 sets bits 1,2,3, else OFF
  }
}
else if monochrome mode, set foreground color {
  BLUE ON if bit 1 set (mask 0x1)
  RED ON if bit 2 set (mask 0x2)
  GREEN ON if bit 3 set (mask 0x4)
}
0x55-0x5b Palette Write Writes to the palette. The index written to is the difference between the port number and 0x54.
0x5c-0x5f