3 ms·
With a microcode update that ruins FDIV performance, sure. Even at that time there were CPUs still using microcoded division, like the AMD K5.
by jeffbee 2y ago
With a microcode update that ruins FDIV performance, sure. Even at that time there were CPUs still using microcoded division, like the AMD K5.
- Netch 2y agoThis division, using SRT loop with 2 bit output per iteration, perhaps would have already been microcoded - but using the lookup table as an accelerator. An alternative could use a simpler approach (e.g. 1-bit-iteration "non-restoring" division). Longer but still fitting into normal range. But if they had understood possible aftermath of non-tested block they would have implemented two blocks, and switch to older one if misworking was detected.
- tliltocatl 2y agoThat was before dark silicon and real estate was still somewhat expensive, so probably having two blocks wasn't really an option.