Alien 8: Routine at C8FF

C8FF: Read Controls

Used by the routines at HandlePlayerLegs and HandleTurningLegs.

Reads the controls that the player is using and stores them in ControlsPressed. The controls are made into a byte, with bit 0 for left, bit 1 for right, bit 2 for walking forward, bit 3 for jumping and bit 4 for picking up and dropping an object. Bit 5 is set by ReadControls_Finish. No controls are read while the game over scene is shown or the game has been completed.

Output
C	The controls

Pick the reader from ControlMethod.

ReadControls

C8FF

LD A,($5B23)

Fetch GameCompletedFlag.

C902

LD C,A

Copy it to C.

C903

LD A,($5B24)

Fetch GameOverFlag.

C906

OR C

Merge C.

C907

LD C,$00

Set C to 00.

C909

JP NZ,ReadControls_Finish

Jump to ReadControls_Finish if they are not zero.

C90C

LD A,($5B04)

Fetch ControlMethod.

C90F

RRCA

Rotate bits 1 and 2 into bits 0 and 1.

C910

AND %00000011

Keep only bits 0 and 1.

C912

JP Z,ReadKeyboard

Jump to ReadKeyboard if they are zero.

C915

DEC A

Decrement A.

C916

JR Z,ReadKempstonJoystick

Jump to ReadKempstonJoystick if it is zero.

C918

DEC A

Decrement A.

C919

JR Z,ReadCursorJoystick

Jump to ReadCursorJoystick if it is zero.

Continue on to ReadInterface2Joystick.

View the equivalent code in;