3 ms·
> MIPS was perhaps the integer equivalent to FLOP, still used in modern microcontrollers because the 8051 at 12MHZ would only execute 1MIPS (12 clocks per instr
by gumby 3y ago
> MIPS was perhaps the integer equivalent to FLOP, still used in modern microcontrollers because the 8051 at 12MHZ would only execute 1MIPS (12 clocks per instruction)
Actually the origin of this term was VAX MIPS (VAX 780 specifically) because that was a ubiquitous, pretty fast for its time minicomputer. There were faster machines, and slower mainframes still being built, but that was what the late 70s were like.
When the 8051 was released in 1980 it surely didn’t run at 12 MHz! Back then the Z80 sold because it could run 8080 code at a blistering 2 MHz.
BTW the benchmark for FLOPS in those days was Whetstone, hence the otherwise weird name “Dhrystone”
- dragontamer 3y agoThe 1981 manual for the 8051 contains numerous references to 12MHz. http://bitsavers.informatik.uni-stuttgart.de/components/intel/8051/MCS-51_Users_Manual_Jan81.pdf http://bitsavers.informatik.uni-stuttgart.de/components/inte... It was 12T clocked: even though the clock was 12MHz, it would only operate at 1MHz / 1MIPS, because it took 12-clock-ticks to even perform one addition. IIRC, there was a standard crystal (11.0592 MHz crystal?? I forget exactly) for the communications at the time. So going just above 11 MHz (or really, just above 11.0592 MHz) was needed for reliable serial comms.
- gumby 3y agoWow, right on page 1-2! I'm surprised -- I don't remember anything running that fast back then. Thanks. (Love those old Intel books too) Nevertheless, FWIW, MIPS started out as Vax MIPS, and at first people often used to write "VAX MIPS".
- vardump 3y ago8051 might run at 12 MHz, but actual instructions run in multiples of 12 clock cycles. Realistic code on a 8051 runs only about 450k-800k instructions per second @12 MHz.