4 ms·

How many of these are still relevant? x86 has an instruction for crc, bswap, as well as nop now.

• dr_zoidberg 11y ago
  Now almost every code to be run is cache-bound for performance, not cycle-bound. So this gems, while may still work, may not be the best means to achieve optimal performance. Optimizing cache access is what brings the biggest speedups today -- see for example NumExpr[1]. [1] https://github.com/pydata/numexpr https://github.com/pydata/numexpr
  • uxcn 11y ago
    Cache is extremely important, but most of these operate strictly on values in registers. So, losing cycles due to cache misses, latency, contention, etc... isn't a bottleneck. A lot of these are crucial enough that they've been codified in transistors now, and generally can execute in a cycle without consuming extra registers. There are still some very valid bit tricks though.
    • dr_zoidberg 11y ago
      Well I read some and had the impression they were going for speed or low cycle count. Indeed, most surely still work (there doesn't seem to be anything that is processor-specific). Unfortunately my asm is rustier than I thought and I find it quite demanding to read and fully understand them.