Can I edit the program counter value ?
help me!

What exactly are you attempting to accomplish?

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Welcome.

Please give a little more context. Do you mean in assembly-language source code? Most assemblers use ORG ____ , where the parameter tells what value you want. "ORG" stands for "origin." Some assemblers need a dot before it, like ".ORG" or similar. Other ones will use the asterisk, like *=____. What assembler are you using? You can use these many times in your code, even for the same program, to pick up at another address. (There may be several reasons to do this, which I may get into later.)

Or, if you mean to jump or branch, use the JMP or JSR or B__ (ie, the BNE, BEQ, BMI, BPL, BCC, BCS, BVC, BVS, BRA, BBS, or BBR instructions). RTS returns from a subroutine, and RTI from an interrupt-service routine (ISR), also affecting the program counter. Actually, these can be used in other contexts too, not just subroutines and interrupts.

Also, giving the topic a title that's descriptive and gets people's interest will give you more success at getting answers.

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http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

Welcome.

There is no direct way to modify the program counter arithmetically at run-time which is what a lot of people would like to be able to do. There are several indirect methods.
The desired value of the program counter minus one can be pushed on the stack then an RTS executed. Or the desired value could be stored in memory then a memory indirect jump JMP ($addr) performed. Or a jump instruction may be stored in memory then self modifying code used as modifying the jump instruction to point to the desired address.

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