My 1988
KK Computer uses register renaming... even though the term itself was unknown to me at the time.
KK is a 65C02 augmented with 6 new registers and 44 new instructions. Register K0 is the default source for address bits A23-A16, and thus has similarities to PBR and DBR on the 65C816 (also unknown to me at the time).
As the homegrown mnemonics imply, a far jump or far call (JMP_K3 or JSR_K3) uses K3 to specify the new A23-A16.
This is accomplished by an apparent swap of K3 with K0. But, as Ed explained, it isn't actually the register
contents that change. Instead, there's an XOR gate that changes the behavior of the decoding mechanism that selects K3 as opposed to K0.
-- Jeff
Attachment:
KK Register Diagram.png [ 8.39 KiB | Viewed 575 times ]
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In 1988 my 65C02 got six new registers and 44 new full-speed instructions!
https://laughtonelectronics.com/Arcana/ ... mmary.html