[stella] Why do we use the SEI instruction???

Subject: [stella] Why do we use the SEI instruction???
From: Dennis Debro <ddebro@xxxxxxxxxxxxx>
Date: Mon, 4 Aug 2003 10:49:48 -0400
Manuel responded to my message below...

>Hi Dennis!
>> - You can remove the SEI instruction. It's not needed 
>> (saves 1 byte) 
>> - Using Andrew Davie's clear routine will save you 2 
>> bytes
>Uhm... using his CLEAN_START macro will immediately 
>reintroduce the SEI... ;-)

Which brought me to ask why do we use SEI in the first place? The 6507 has no interrupt capabilities (aside from BRK and the timer interrupt at $285), right. So it seems like putting SEI in your code wastes a byte. So should CLEAN_START remove it too?

If this has been asked before then please excuse me. I searched the list and couldn't find anything. Then again the search process doesn't seem to be working very well.

Take care,

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