endianness : Re: timer.c and ckinit.c Re: Timer resolution et al : Read_timer()
sashti srinivasan
svasn_rtems at yahoo.com
Sat Mar 13 09:39:19 UTC 2004
Hello,
Lots of thanks for making things much clearer.
Now I hope that I am somewhat clear, still I have
one problem in Read_timer() related to the endianness
of x86. Here is a fragment from this routine:
These lines latch the value of timer0, then reads lsb
first and msb next.
outport_byte(TIMER_MODE, TIMER_SEL0|TIMER_LATCH);
inport_byte(TIMER_CNTR0, lsb);
inport_byte(TIMER_CNTR0, msb);
This lines store two bytes on variable clicks.
clicks = (msb << 8) | lsb;
My doubt is, since i386 is little endian, why this
line is written like this instead of:
clicks = (lsb << 8) | msb;
I guess whatever is written already is correct,
something is wrong with my understanding. Very
sorry if my doubt is a trivial one.
With Regards
Srinivasan
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