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6502 trashing memory cycles...
- Subject: 6502 trashing memory cycles...
- From: "bieling@terra.es" <bieling@terra.es>
- Date: 4 Mar 2007 11:12:10 -0800
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Hello,
I've been having a look at the 6502 instruction details in the
databooks and in uta2,p20..23. I've never realized that the 6502
trashes so many memory cycles here and there. For example 3 out of the
6 cycles of an RTS are useless. 2 out of 4 of a PLA are useless, 1 out
of 2 of a DEX are useless.
The table in uta2,p22, shows the instructions classiffied in 29
groups. 22 out of the 29 opcode groups trash between 1 and 3 memory
cycles..!
A clever circuit could make good use of so many memory cycles for some
other purpose... any ideas ?
Jorge.