Arm development systems

timing-sensitive

main(). That

timing.

isn't very

CPU

Or, depending on the processor, .3 to 10. Then there are the processors with decoupled/asynchronous I/O... Super-scalars...

Again, you mentioned NOP timing, which is just nuts with a modern CPU architecture.

Reply to
krw
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Yes. My first "benchmark" attempt came up like this:

Double Precision: 0.270us / 32.406 cycles /multiply 0.238us / 28.652 cycles /add 0.234us / 28.152 cycles /divide Single Precision: 0.181us / 21.723 cycles /multiply 0.134us / 16.101 cycles /add 0.130us / 15.602 cycles / divide

Unfortunately I posted it before I realised my dumb benchmarking loop was driving some of the variables to zero. So the FP routines could and did exit early!

--

John Devereux
Reply to
John Devereux

timing-sensitive

main(). That

timing.

yet--I'm

isn't very

shorter

Of

much

is

speed

like CPU

ISR,

it's

like

I dug into this a bit more, and discovered that NXP claims a fixed

12-cycle interrupt latency, so it looks as though they solved this problem already. STM32F and L both say "maximum 12 cycles".

So obviously PICs still rule for timing. ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net
Reply to
Phil Hobbs

timing-sensitive

main(). That

timing.

yet--I'm

isn't very

shorter

I'm

Of

much

is

speed

like CPU

ISR,

it's

like

formatting link

The LPC3250 has *one* interrupt vector; the front-end of the ISR has to figure out whodunnit. This is PDP-8 technology.

--

John Larkin, President       Highland Technology Inc
www.highlandtechnology.com   jlarkin at highlandtechnology dot com   

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME  analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators
Reply to
John Larkin

timing-sensitive

main(). That

timing.

yet--I'm

isn't very

shorter

Of

much

is

speed

like CPU

ISR,

it's

like

My early stuff has started to get reinvented too. ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net
Reply to
Phil Hobbs

timing-sensitive

main(). That

timing.

yet--I'm

isn't very

shorter

I'm

Of

much

is

speed

like CPU

ISR,

it's

like

formatting link

Doesn't do anything, but it's sure consistent! ;-)

Reply to
krw

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