On 12/16/2015 08:11 AM, Jisheng Zhang wrote:
Dear Daniel,
On Tue, 15 Dec 2015 21:59:30 +0100 Daniel Lezcano wrote:
On 11/25/2015 04:42 PM, Jisheng Zhang wrote:
Let's assume the counter value is 0xf000000, the pistachio clocksource
read cycles function would return 0xffffffff0fffffff, but it should
return 0xfffffff.
We fix this issue by calculating bitwise-not counter, then cast to
cycle_t.
Signed-off-by: Jisheng Zhang <[email protected]>
Hi Jisheng,
I tried to reproduce this behavior on x86_64 but without success.
On which architecture did you produce this result ? Do you have a simple
test program to check with ?
I have no HW platforms with pistachio, just read the code and run the
following test code in x86_64 and x86_32:
#include <stdio.h>
unsigned long long pistachio_clocksource_read_cycles()
{
unsigned int counter = 0xf000000;
return ~(unsigned long long)counter;
}
int main()
{
printf("%llx\n", pistachio_clocksource_read_cycles());
return 0;
}
Ok, I reproduced it. I had an issue with the signed/unsigned type.
That's a good catch !
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