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Getting the raw state of the keyboard with CauseWay? (Developers)

posted by Japheth(R) Homepage, Germany (South), 21.10.2019, 14:58

> If anyone here has some comments on the code, please share.

The STI opcode isn't really necessary, since interrupts should already be disabled when the routine is called.

Readinf/Writing port 0x61 is most likely a requirement for PC/XT machines only, to send an "acknowledge" (ACK) to the keyboard controller that the request has been handled. On AT and newer machines, reading port 0x60 is sufficient for this.

Writing 0x20 to port 0x20 sends ACK to the PIC.

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MS-DOS forever!

 

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