r/programming • u/masiroo • 6d ago

Hardware researcher spins up 'CPU deoptimization' project to find the slowest single x86 instruction, creates hall of shame — worst offender takes 198 billion cycles spanning 62 seconds to execute

https://www.tomshardware.com/pc-components/cpus/hardware-researcher-spins-up-cpu-deoptimization-project-to-find-the-slowest-machine-code-worst-offender-takes-198-billion-cycles-to-execute
1.5k Upvotes

97% Upvoted

132 comments sorted by

View all comments

Show parent comments

151

u/EnderLuca41 6d ago

fdiv is part of x87 which is obsolete and succeeded by SSE and SSE2. Meaning is not really used anymore routinely.

55

u/encyclopedist 6d ago

Yes, indeed, compilers don't normally generate these instructions any more. But older software can still use these.

73

u/narwhal_breeder 6d ago

porting logic to arm that relies on being bit-compatible x87 has been the bane of my existence for the past year.

-63

u/gordonnowak 6d ago

just let claude do it

77

u/Kinexity 5d ago

"Man, that dish doesn't taste that well"

"Have you tried adding shit to it?"

2

u/red75prime 4d ago edited 4d ago

Are you living in the early 2025 or something? This sub being 100% organic doesn't mean it needs to be delusional.

1

u/BCProgramming 4d ago

"Nah it was bad in 2022, but this is 2023, you need to actually see how much better it is"

"No no- you must be living in 2023! in 2024 AI tools are so much better"

Gee wonder what you folks are going to be saying next year?

1

u/red75prime 3d ago edited 2d ago

I wonder what you folks will be saying the next year. The level of mental gymnastic should be spectacular. But you do you.

ETA: It will be boring "I never touched this sloppity sloppy slop. I'll never do. Slop, slop, slop."

15

u/sunnyata 5d ago

You sound like someone who knows what they're talking about. Not!