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- URL: https://x.com/NOTimothyLottes/status/2077224595858280506
- Author: NOTimothyLottes (@NOTimothyLottes)
- Posted: 2026-07-15 02:51:51
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1/ @NOTimothyLottes
One advantage of SAR (aka signed ’>>’) is that the shift-by operand HW uses only the 5|6 LSBs automatically. So if you have a mixed used control word, you don’t have to mask out the MSBs. Can save an instruction.
2/ @NOTimothyLottes
Working through an idea of a single uber-instruction interpreted language for code generation. Meaning something that never misses the instruction cache and executes fully out of the micro-op cache. Fully data driven with a direct map 64k entry symbol table.
3/ @NOTimothyLottes
Borrows some ideas from SIMD GPU programming. Like instead of branching/predicating to avoid stores, just store to a discarded area (like a negative offset on the GPU, or a designated trash address on the CPU).
4/ @NOTimothyLottes
Don’t want exit condition logic in the infinite loop, so exit will have to be having the program store an exit value into a set address, and an external watchdog polling for exit at some sleep frequency.
5/ @NOTimothyLottes
SAR on a control word can in theory grab 3 values.
SF (sign flag) is set to MSB bit
CF (carry flag) is set to what shifts into bit -1
and output
The SF and CF can be used for CMOVcc
Output can be used for another shift (after CMOVccs)