fx-9860G/GII detect the MAIN MENU (C)

[SimonLothar]

Purobaz asked:
when using a persitent timer on a fx-9860G/GII, how can we detect, whether the MAIN MENU or some Addin/BuildIn is on top, inside of the timer handler.

A fitting syscall has not been found to achieve this.
But the following code finds the address of a certain system variable, which gives the answer.
This should be OS-independent.

Code: Select all

unsigned int ea;
unsigned int j;
ea = *(unsigned int*)0x8001007C;
ea += 0x0490*4;
ea = *(unsigned int*)( ea );
j = *(unsigned char*)( ea + 1 );
j *= 4;
j = ( ea + j + 4 ) & 0xFFFFFFFC;
j = *(unsigned int*)( j ) + 1;

return *(unsigned char*)j;


returns 3 if the MAIN MENU is active
else 0

Purobaz verified this within a timer.

The scheme should work with interrupt handlers as well.