cpu indirect addressing modes

Discuss emulation of the Nintendo Entertainment System and Famicom.

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mattmatteh
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cpu indirect addressing modes

Post by mattmatteh »

does the 6502 have an internal register for indirect addressing modes to store the pointer? also, is there an internal register to hold the address for the address bus?

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tepples
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Re: cpu indirect addressing modes

Post by tepples »

mattmatteh wrote:does the 6502 have an internal register for indirect addressing modes to store the pointer?
Yes. There has to be at least some register fed to the internal ALU to allow the effective address to be built up. Why do you need this? Are you doing a state-machine implementation of the 6502?
also, is there an internal register to hold the address for the address bus?
How to answer this in the most helpful way depends on what you are trying to do.
mattmatteh
Posts: 345
Joined: Fri Jul 29, 2005 3:40 pm
Location: near chicago

Post by mattmatteh »

the cpu core works in my emu, i was just making some changes and cleaning up some stuff. i figured the 6502 has those registers and i was going to match that in my code. i know the hardware doenst have to be exact, but i have those variables anyway.

i took a cpu design class several years ago, so i understand most/all of the 6502. just need to refresh some of it.

thanks matt
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