Difference between revisions of "GeneveOS XOP Definitions"

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== XOP five: Keyboard ==
== XOP five: Keyboard ==


{| class="xop5"
[[Geneve keyboard control]]
| Input
| R0 LSB
| Scan mode
|-
| Output
| R0 LSB
| Scan mode
|-
|
| R1 MSB
| Scan code
|-
|
| R2 MSB
| Joystick Y value (see TI, 8376)
|-
|
| R2 LSB
| Joystick X value (see TI, 8377)
|-
|
| EQ bit
| if a new key has been pressed
|-
|}
 
The scan modes 0-5 are identical to those in the TI console. Scan mode 7 is specifically used to check the BREAK key (EQ set), and scan mode 8 returns the raw scan code in R1 MSB. If no key was pressed, R1 MSB contains 0xFF.


== XOP six: Video ==
== XOP six: Video ==

Revision as of 14:29, 17 July 2016

MDOS makes frequent use of XOPs and offers them for user programs. An XOP (extended operation) is a special command of the TMS processor family which causes a context switch, transferring control to a location that is specified in a table.

Compared to common architecture concepts, the XOP is TI's way of implementing a system call.

General usage of XOPs

XOP five: Keyboard

Geneve keyboard control

XOP six: Video

XOP seven: Memory

MDOS Memory Management Functions

XOP eight: Device operation

XOP nine: Utilities

XOP ten: Maths

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