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Altera_Forum
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17 years ago

Nios II Program Counter

Is there anyway to access the Nios program counter from the hardware (instead of using instruction like nextpc..) ? :confused:
Altera_Forum's avatar
Altera_Forum
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17 years ago

You can only read it via the nextpc instruction.

From the NIOS II instruction set reference: 


nextpc
get address of following instruction
Operation: rC ←  PC + 4
Assembler Syntax: nextpc rC
Example: nextpc r6
Description: Stores the address of the next instruction to register rC. 
Usage: A relocatable code fragment can use nextpc to calculate the address of its data 
segment. nextpc is the only way to access the PC directly.
Exceptions: None
Instruction Type: R
Instruction Fields: C = Register index of operand rC

Obviously you can modify the program counter via jump and branch commands.

Jake