Syscalls

Officially supported functions

When looking for officially supported methods in external apps, you can look in .local/lib/node_modules/nwlink/dist/eadk/eadk.h (adapt the path based on how you installed nwlink).

This file is also available in Epsilon source code at eadk/include/eadk/eadk.h.

Manual syscalls

Epsilon external apps are directly talking to the kernel the same way as the userland does. It's working based on SVC calls.

The SVC table can be found at ion/src/device/shared/drivers/svcall.h in Epsilon's source code.

Some of these calls are available in external apps through functions, but not everything is available.

For example, to enter disable On/Off and Home keys, we need to call unavailable functions (willExecuteDFU and suspend), so we call them by hand.

To use them, you just need to use asm("svc <SVC_INDEX>"). To suspend the calculator, you would call asm("svc 44"), as in the SVC table, SVC_POWER_SUSPEND is declared as 44.

However, calling functions this way is not guaranteed to work on every Epsilon version, as SVC numbers could change or functions could simply be removed. If a function is available through EADK, you should use it.