maemo.org - Talk - View Single Post - N900 high precision low latency timer code

joern	2010-09-13 , 22:17
Posts: 1 \| Thanked: 0 times \| Joined on Sep 2010	#1

To precisely time small snippets of C code there is a need for a high-precision, low latency, wall clock timer. The x86 and most other architectures provides asm inlines to read the processor clock. With ARMv7 this should be possible with code like

Code:

MCR p15,0,<Rt>,c9,c12,1  !enable counter
...
MRC p15,0,<Rt>,c9,c13,0  !read counter

However, attempting to use this with GCC asm inline on the N900 returns Illegal instruction. Is there any other mechanism to achieve this ?

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