Is there any possiblility/chance at the assembly level to get, manipulate the value of the program counter register. Is it wasn't easy to change the value at the very low-level of system??

With C programming this facility can be incorporated and I need some pointers to implement the above said at the Low-level.

Then to modify it, can you change the address pointed to currently by it to the address of whatever you wanted.  I don't think you can do just a MOV

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I've got spurs that jingle jangle jingle.
As I go riding merrily along.
And they sing, "Oh, ain't you glad you're single?"
And that song ain't so very far from wrong.

MOV PC,EAX can be simulated with JMP [EAX] or whatever, or by pushing the new address onto the stack and doing a RET (you can also load the PSW at the same time by doing an IRET)

One nice thing about the PDP-11 was you could auto-increment/auto-decrement the PC for fetching parameters inline, or trashing the whole of memory by doing MOV (PC)--, (PC)-- which copied itself thru the whole of memory *backwards* until it fell off at location $0000 hehehe...

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