83Plus:BCALLs:52F6

Synopsis

Unofficial Name: SetAppRestrictions

BCALL Address: 52F6

Minimum OS Version: 2.40

Enable specified "TestGuard 2" app/program restrictions.

Inputs

• A = 0: disable app by name
  • OP1 = name of app to disable
• A = 1: disable all apps
• A = 2: disable programs
• A = 3: disable programs and all apps
• A = 4: set permission bitmap
  • OP3 (14 bytes) = new bitmap to be ANDed with current bitmap

Outputs

• Carry set if A = 0 and the requested app does not exist
• Otherwise, carry reset, regardless of the effect or lack thereof

Destroys

• AF, BC, DE, HL
• OP1-OP2, ramCode, probably other areas

Comments

Note that this routine is cannot remove restrictions, only create them.

The permission bitmap, used by the A = 4 option, is fourteen bytes and is arranged as follows:

• Byte 0, bit 0 is reset to disable execution and editing of both BASIC and assembly programs in the OS.
• The remaining bits of byte 0 appear to be unused, but might be used in the future for other global permission states.
• Byte a, bit b (a > 0) is reset to disable execution of the application with base page 8a+b. (In other words, the pages are given in "memory order," rather than "installation order" as with the app presence bitmap.)
• The last 8 bytes are unused on the 84+ BE (but the corresponding bytes of OP3 are still copied to the certificate.)

Remember that you can clear all restrictions by receiving any file over the link, or by manually sending a file.