83Plus:Hooks:9B98

Synopsis

Name: Y Equ Hook

Hook Pointer Block Address: 9B98

Hook Enable BCALL: 4FCF

Hook Disable BCALL: 4FD2

Hook Call BCALL: (none known)

Hook Active Flag: 4, (iy + 35h)

This hook allows you to change the way the Y Equ app functions.

Using the Hook

These different values, passed in a, determines what the hook should do.

• 0: The calculator is switching to the Y= app.
• 1: The calculator is switching to the sign in front of y1..y0 from. This isn't called when moving up and down through these signs
• 2: Preparing to draw the sign in front of y1..y0. If you want your own sign there, just use PutC and abort the drawing of the sign by the OS.
  • Zero flag: Clear to abort the drawing of the sign.
• 3: Preparing to draw plot1..3
  • Zero flag: Clear to abort the drawing of the plot1..3 texts.
• 4: Preparing to switch to the plot1..3 line.
  • Zero flag: Clear to abort the action of switching to the plot1..3 line.
• 5: Preparing to en/disable the function (inverting the = sign)
  • c: Contains the appropriate that will be executed. It can be changed to do the opposite action.
    • c=0 Preparing to disable the function
    • c=1 Preparing to enable the function
  • Zero flag: Clear to abort the change
• 6: A key has been pressed
  • b: Contains the GetKey equivalent of the key being pressed. This can be changed to simulate another keypress.
  • Zero flag: Clear to ignore the keypress
• 7: This is called after a=5 when it's turning on of off the = sign.
  • L: Contains the function being edited.
• 8: Preparing to draw the = sign. If you want your own sign there, just use PutC and abort the drawing of the sign by the OS.
  • Zero flag: Clear to abort the drawing of the = sign.
• 9: Preparing to switch the cursor to another function

Comments

The above information is based on research in func mode only.