5 ms·

I love the ridiculousness of this. What's faster? The dual-core Cortex M0+ at 133MHz in his "wifi card"? Or the Intel 80486SX at 33MHz in his laptop?

dmitrygr 4y ago
The C-M0 and by FAR. A 486 would be lucky to hit 0.4 instructions per cycle on a good day with much luck. C-M0 can maintain a IPC of 0.8 for most code (loads and stores are 2 cy, all alu stuffs are one).
- rvense 4y ago
  Most of these small ARM micros are an external memory interface and a good OS away from being a mid-90's workstation. The larger ones (high-end Cortex-Ms) are probably comparable to Powermacs of the early 2000's.
  - dmitrygr 4y ago
    yes, in fact: http://dmitry.gr/?r=05.Projects&proj=33.%20LinuxCard http://dmitry.gr/?r=05.Projects&proj=33.%20LinuxCard
- vardump 4y ago
  486 ALU stuff is mostly 1 cycles as well (other than shifts, MUL and DIV, and all the weird stuff like AAD), as well as stores and loads. Taken conditional jumps are 3 cycles, non-taken 1 cycle, so loop unrolling helps a lot on 486. You can approach 0.8 IPC on 486, assuming you know about AGI stalls and other quirks. General 486-era C-compiler produced code, though, would be lucky to hit 0.4 IPC.
  - dmitrygr 4y ago
    I was taking intel's 80486 promo materials at face value. Plus 486 ALU may be 1-cycle but loads and stores are not 2-cycle like they are for C-M0 so it'll still lose :)
    - vardump 4y ago
      At least this page says 486 stores and loads are 1 cycle: https://zsmith.co/intel_m.php#mov https://zsmith.co/intel_m.php#mov But it's been over 25 years since I last wrote asm for a 486 CPU.
jabbany 4y ago
Heh, it reminds me of this gem: https://www.youtube.com/watch?v=ar9WRwCiSr0 https://www.youtube.com/watch?v=ar9WRwCiSr0 which does something similar... using a modern device to give old devices essentially capabilities beyond what they should be able to do.
tyingq 4y ago
Similar for: the 1541 disk drive that you would pair with a Commodore 64. It had a 6502 CPU in it, and was clocked a little faster than the 6510 CPU in the C64 itself. The Apple LaserWriter'ss 68k cpu was clocked at 12Mhz, intended to be used with Macs having a 68k CPU clocked around 7.8Mhz.

dmitrygr 4y ago

The C-M0 and by FAR. A 486 would be lucky to hit 0.4 instructions per cycle on a good day with much luck. C-M0 can maintain a IPC of 0.8 for most code (loads and stores are 2 cy, all alu stuffs are one).

rvense 4y ago
Most of these small ARM micros are an external memory interface and a good OS away from being a mid-90's workstation. The larger ones (high-end Cortex-Ms) are probably comparable to Powermacs of the early 2000's.
- dmitrygr 4y ago
  yes, in fact: http://dmitry.gr/?r=05.Projects&proj=33.%20LinuxCard http://dmitry.gr/?r=05.Projects&proj=33.%20LinuxCard
vardump 4y ago
486 ALU stuff is mostly 1 cycles as well (other than shifts, MUL and DIV, and all the weird stuff like AAD), as well as stores and loads. Taken conditional jumps are 3 cycles, non-taken 1 cycle, so loop unrolling helps a lot on 486. You can approach 0.8 IPC on 486, assuming you know about AGI stalls and other quirks. General 486-era C-compiler produced code, though, would be lucky to hit 0.4 IPC.
- dmitrygr 4y ago
  I was taking intel's 80486 promo materials at face value. Plus 486 ALU may be 1-cycle but loads and stores are not 2-cycle like they are for C-M0 so it'll still lose :)
  - vardump 4y ago
    At least this page says 486 stores and loads are 1 cycle: https://zsmith.co/intel_m.php#mov https://zsmith.co/intel_m.php#mov But it's been over 25 years since I last wrote asm for a 486 CPU.

jabbany 4y ago

Heh, it reminds me of this gem: https://www.youtube.com/watch?v=ar9WRwCiSr0 https://www.youtube.com/watch?v=ar9WRwCiSr0 which does something similar... using a modern device to give old devices essentially capabilities beyond what they should be able to do.

tyingq 4y ago

Similar for: the 1541 disk drive that you would pair with a Commodore 64. It had a 6502 CPU in it, and was clocked a little faster than the 6510 CPU in the C64 itself. The Apple LaserWriter'ss 68k cpu was clocked at 12Mhz, intended to be used with Macs having a 68k CPU clocked around 7.8Mhz.