I'm reading a book on Windows Internals and there's something I don't understand:

"The kernel handles software interrupts either as part of hardware interrupt handling or synchronously when a thread invokes kernel functions related to the software interrupt."

So does this mean that software interrupts or exceptions will only be handled under these conditions:

a. When the kernel is executing a function from said thread related to the software exception(trap) b. when it is already handling a hardware trap

Is my understanding of this correct?

The next bit:

"In most cases, the kernel installs front-end trap handling functions that perform general trap handling tasks before and after transferring control to other functions that field the trap."

I don't quite understand what it means by 'front-end trap handling functions' and 'field the trap'?

Can anyone help me?