Bytes and cycles for prefix opcodes
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Assessment
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Newbie friendliness
- 35/100
- Issue type
- Documentation
- Clarity
- Mostly clear
- Activity status
- Stale
- Domain
- documentation
Research direction
Compare the main opcode table's PREFIX entry with the separate table of 0xCB-prefixed opcodes, focusing on how bytes and cycles are presented. Determine a clear way to explain that the prefix is included in the prefixed instruction totals, then verify that the tables or accompanying note no longer invite the reported confusion.
Written by the indexing model from the issue text.
Description
Some people (on the emudev Discord server) seem to be confused by the fact that the table lists 0xCB as 1 byte and 4 cycles, while all the 0xCB-prefixed opcodes in the separate table add that 1 byte and those 4 cycles to their totals.
For example, RLC B at 0xCB 0x00 is listed as taking 2 bytes and 8 cycles, but in the main table PREFIX at 0xCB is listed as taking 1 byte and 4 cycles.
That's not incorrect per se, since fetching the 1-byte prefix takes 4 cycles, so I'm not sure what the best "solution" would be. Perhaps just a footnote?
- Dominant language
- SCSS
- Stars
- 29
- Forks
- 10
- PR merge metrics
- No merged PRs in 30d
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