Module softkeys 

What the six menu keys show now (48SX, 48GX, 49G), read from RAM without pressing a key: the current menu (its pointer, wiki: hardware/hp48-system-ram, “Menu”) and its page (the first key shown, same section), the menu’s keys from the ROM’s own definition (crate::menus), the VAR menu’s from the current directory.

Only while the stack has the keyboard (crate::screen): an input form, a choose box or another application draws its own keys. A menu the ROM builds in RAM (the 49G’s TOOL menu, a form’s menu), the CST menu and a menu whose definition gives no keys read as unknown.

Structs

ShownKey

One menu key as the screen shows it.

Constants

PAGE

Keys on one page of a menu.

VAR_MENU

The VAR menu’s number (2 MENU).

Functions

read

The six menu keys the screen shows now, read from RAM while the ROM waits for a key (48SX, 48GX, 49G); None where they are not known (another screen has the keyboard, a menu built in RAM, CST). defs are the ROM’s menus (crate::menus::read).

shown

The six keys of menu number on the page starting at key first: from the definition in defs, or for the VAR menu from variables (the current directory’s, newest first). None where the keys are not known.

signature

What identifies the menu shown and what its keys depend on, read cheaply: the menu pointer, the page, the current directory, the end of HOME, the data stack’s top and the return stack’s top. When none of these moved, read gives the same keys.