Joystick_Read 0
Joystick
» SWI Calls
» Joystick_Read
» Joystick_Read 0
Joystick_Read 0
(SWI &43F40)
| Entry | |
|---|---|
| R0 | 0 + stick number in bits 0-7 |
| Exit | |
|---|---|
| R0 | State: |
| Bits 0-7: Signed Y value (-127 down, +127 up) | |
| Bits 8-15: Signed X value (-127 left, +127 right) | |
| Bits 16-23: Buttons (such as the fire button) | |
| Bits 24-31: Reserved |
Use
The purpose of this call is to read the latest 8 bit joystick value.
Notes
For digital joysticks, fixed values of ±64 will be returned when the switches are activated. Due calibration drift in analogue circuitry it is recommended to use the band -&20 to +&20 as an “at rest” region.
Prior to a call to this SWI the joystick hardware may be disabled or powered down. As it is the buffered value that is returned, triggering a new conversion to be scheduled, the very first call to this SWI will return X=0 Y=0.
See also
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