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| author | Juan J. Martinez <jjm@usebox.net> | 2023-05-08 22:52:26 +0100 |
|---|---|---|
| committer | Juan J. Martinez <jjm@usebox.net> | 2023-05-08 22:52:26 +0100 |
| commit | 0194f9c3bbb460647ce5a22e4e8e7859398d8da0 (patch) | |
| tree | 3a4b5cd529f0f3c5e1b152418038ec1587e515c8 /README.md | |
| parent | 676046a8e532fb8cb62d558dac6fba07232d1f70 (diff) | |
| download | tr8vm-0194f9c3bbb460647ce5a22e4e8e7859398d8da0.tar.gz tr8vm-0194f9c3bbb460647ce5a22e4e8e7859398d8da0.zip | |
Support read from the screen
Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 11 |
1 files changed, 7 insertions, 4 deletions
@@ -77,8 +77,10 @@ On a successful port call, the read value equals to the port number, so the call To draw with the blitter the following steps are required: 1. put the blitter in settings mode using control port `0xb0` -2. provide the source address, and destination coordinates (x, y, width and height) using settings port `0xb1` -3. set the blitter in one of the write modes using the control port `0xb0` +2. provide an address, and screen coordinates (x, y, width and height) using settings port `0xb1` +3. set the blitter in one of the draw modes using the control port `0xb0` + +The address will be the source data in write mode, and the destination in read mode. Step 3 can be repeated as many times as needed, the blitter will keep the settings until the control port is set in settings mode. @@ -87,9 +89,10 @@ The settings byte is as follow: | Bits | Effect | --- | --- | | `x0000000` | Set blitter in settings mode | -| `0000000x` | Write | +| `0000000x` | Write to video RAM | | `000000x0` | The source includes a transparent bit | -| `0xxxxx00` | Unused | +| `00000x00` | Read from video RAM | +| `0xxxx000` | Unused | Example: |