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Originally Posted by meynaf
Doh, perhaps i don't even remember exactly.
But isn't it that ipl=6 allows both 6 & 7 (anything >=6) but ipl=7 only 7, while ipl=0 allows >=0 but there is no level 0 so it's the same as 1 ?
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ipl=6 doesn't allow any maskable IRQ (same as 7)
ipl=0 allows >0, so every IRQ
ipl=1 allows >1, and so on
Quote:
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Perhaps because TST was implemented with similar hardware as CLR, NOT, NEG, NEGX, which were all read-modify-write (including, wrongly, CLR).
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Well, I can understand for the listed instructions, that are all with modification of the destination, but not for a read only operation!
(if same die part is used for this operation is sure a bad implementation, but ehi, is a 1979 project with limited transistor usable
)
I must always remember not to use it
