|
Routines |
| Prev: B0B1 | Up: Map | Next: B0FA |
|
Used by the routine at HandlerControls.
|
||||||||
| ReadKempstonJoystick | B0D9 | IN A,($1F) | A=controls. | |||||
|
Initialise the controls as "none" in C.
|
||||||||
| B0DB | LD C,$00 | C=00. | ||||||
|
Check joystick "RIGHT".
|
||||||||
| ReadKempstonJoystick_Right | B0DD | BIT 0,A | If bit 0 is set/ "RIGHT" is NOT being pressed then jump to ReadKempstonJoystick_Left. | |||||
| B0DF | JR Z,ReadKempstonJoystick_Left | If not jump to ReadKempstonJoystick_Left. | ||||||
| B0E1 | SET 1,C | Set bit 1 of C. | ||||||
|
Check joystick "LEFT".
|
||||||||
| ReadKempstonJoystick_Left | B0E3 | BIT 1,A | If bit 1 is set/ "LEFT" is NOT being pressed then jump to ReadKempstonJoystick_Down. | |||||
| B0E5 | JR Z,ReadKempstonJoystick_Down | If not jump to ReadKempstonJoystick_Down. | ||||||
| B0E7 | SET 0,C | Set bit 0 of C. | ||||||
|
Check joystick "DOWN".
|
||||||||
| ReadKempstonJoystick_Down | B0E9 | BIT 2,A | If bit 2 is set/ "DOWN" is NOT being pressed then jump to ReadKempstonJoystick_Up. | |||||
| B0EB | JR Z,ReadKempstonJoystick_Up | If not jump to ReadKempstonJoystick_Up. | ||||||
| B0ED | SET 3,C | Set bit 3 of C. | ||||||
|
Check joystick "UP".
|
||||||||
| ReadKempstonJoystick_Up | B0EF | BIT 3,A | If bit 3 is set/ "UP" is NOT being pressed then jump to ReadKempstonJoystick_Fire. | |||||
| B0F1 | JR Z,ReadKempstonJoystick_Fire | If not jump to ReadKempstonJoystick_Fire. | ||||||
| B0F3 | SET 2,C | Set bit 2 of C. | ||||||
|
Check joystick "FIRE".
|
||||||||
| ReadKempstonJoystick_Fire | B0F5 | AND %00010000 | Keep only bit 4. | |||||
| B0F7 | OR C | Merge the kept bit into C. | ||||||
| B0F8 | LD C,A | |||||||
| B0F9 | RET | Return. | ||||||
| Prev: B0B1 | Up: Map | Next: B0FA |