Lpc2000

I'm seeing slightly different numbers.  
Yesterday I put two lines of code in my C program.
Line 1 was  IOSET0 = xxxx   to set an IO pin.
Line 2 wss  IOCLR0 = xxxx   to clear the same pin.,
This compiled to a total of 8 lines of assemble code using IAR.
When executed, the IO pin stayed high for 2 uS with a 24MHz clock.  
This implies the 8 instruction took over 48 clock ticks.  I was in 
the THUMB mode, and I'll try it again in the ARM mode.  
John

--- In lpc2000@yahoogroups.com, "lpc2100_fan" <lpc2100_fan@y...> 
wrote:
> 
> Hi Arturo,
> 
> your measurement seems very much in line with what ARM is quoting 
for
> the ARM7 core. The core can run in the average over all programs 
they
> tested with 1.9 clocks per instruction. This is not LPC2000 
specific,
> rather ARM7 core specific. As side information, the ARM9 core is
> quoted at 1.3 clocks / instruction, so inherently faster while 
running
> at the same frequency. 
> 
> Now to the possible difference between the chips you might be 
testing.
> A device running 0 wait states will be very close to what you
> measured. If you would use for example external flash memory (or
> internal) and have to insert wait states, you will see this factor
> degrading depending on the number of wait states.
> 
> Another topic you would want to consider is whether you execute ARM
> code or Thumb code. You will execute the same number of ARM or 
Thumb
> instructions during a given time on the LPC2000 but you might find
> that other devices with narrower busses will give you more
> instructions in Thumb mode than in ARM mode. What does this mean?
> Thumb mode has the benefit of reducing your code size by approx. 30
> percent, or in numbers, 7 Thumb instructions replace 5 ARM 
instructions. 
> 
> It takes approx 10 clock cycles to execute the 5 ARM instructions 
on a
> LPC2000 but it takes almost 14 cycles to execute the Thumb
> instructions performing the same task. 
> 
> Your question if related to performance could then be rephrased to 
how
> many clock cycles to perform a task in ARM and Thumb mode and now 
we
> are exactly there what a benchmark is.  It is not as easy as how 
many
> clock cycles per instruction but more how much time to perform a 
given
> task with lots of parameters if comparing different devices. 
> 
> Accept my apologies for this lengthy e-mail but I could not 
resist ;-)
> 
> Cheers, Bob
> 
> 
> --- In lpc2000@yahoogroups.com, "arturo tramontini" <a.t@t...> 
wrote:
> > 
> > someone know how many oscillator clock x instruction cycle?
> > from my measure it's seems about 4 oscillator clock x 
instruction.
> > thank's to all