Messages in this thread | | | Date | Sun, 30 Jul 2006 17:40:10 +0300 | From | Avi Kivity <> | Subject | Re: FP in kernelspace |
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Jiri Slaby wrote: > > Hello, > > I have a driver written for 2.4 + RT patches with FP support. I want > it to work > in 2.6. How to implement FP? Has anybody developped some "protocol" > between KS > and US yet? If not, could somebody point me, how to do it the best -- > with low > latency. > The device doesn't generate irqs *), I need to quickly respond to > timer call, > because interval between two posts of data to the device has to be > equal as much > as possible (BTW is there any way how to gain up to 5000Hz). > I've one idea: have a thread with RT priority and wake the app in US > waiting in > read of character device when timer ticks, post a struct with 2 floats > and > operation and wait in write for the result. App computes, writes the > result, we > are woken and can post it to the device. But I'm afraid it would be > tooo slow. > > *) I don't know how to persuade it (standard PLX chip with unknown > piece of > logic behind) to generate, because official driver is closed and _very_ > expensive. Old (2.4) driver was implemented with RT thread and timer, > where FP > is implemented within RT and computed directly in KS. > > So 2 questions are: > 1) howto FP in kernel > kernel_fpu_begin(); c = d * 3.14; kernel_fpu_end();
-- error compiling committee.c: too many arguments to function
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