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Elite on the BBC Micro

Keyboard: KTRAN [Master version]

Name: KTRAN [Show more] Type: Variable Category: Keyboard Summary: The key logger buffer that gets updated by the OSWORD 240 command
Context: See this variable in context in the source code References: No direct references to this variable in this source file

KTRAN is a buffer that is filled with key logger information by the KEYBOARD routine in the I/O processor, which is run when the parasite sends an OSWORD &F0 command to the I/O processor. The buffer contains details of keys being pressed, with KTRAN being filled with bytes #2 to #14 from the KEYBOARD routine (because KEYBOARD is called with OSSC pointing to buf, and buf is equal to KTRAN - 2). The key logger buffer is filled as follows: KTRAN + 0 Internal key number of any non-primary flight control key that is being pressed KTRAN + 1 "?" is being pressed (0 = no, &FF = yes) KTRAN + 2 Space is being pressed (0 = no, &FF = yes) KTRAN + 3 "<" is being pressed (0 = no, &FF = yes) KTRAN + 4 ">" is being pressed (0 = no, &FF = yes) KTRAN + 5 "X" is being pressed (0 = no, &FF = yes) KTRAN + 6 "S" is being pressed (0 = no, &FF = yes) KTRAN + 7 "A" is being pressed (0 = no, &FF = yes) KTRAN + 8 Joystick X value (high byte) KTRAN + 9 Joystick Y value (high byte) KTRAN + 10 Bitstik rotation value (high byte) KTRAN + 12 Joystick 1 fire button is being pressed (Bit 4 set = no, Bit 4 clear = yes) Other entry points: buf The two OSWORD size bytes for transmitting the key logger from the I/O processor to the parasite
.buf EQUB 2 \ Transmit 2 bytes as part of this command EQUB 15 \ Receive 15 bytes as part of this command .KTRAN EQUS "1234567890" \ A 17-byte buffer to hold the key logger data from the EQUS "1234567" \ KEYBOARD routine in the I/O processor (note that only \ 12 of these bytes are actually updated by the KEYBOARD \ routine)