Hello,
P.F. Tsai wrote:
I am wondering about what happens after the "hlt" instruction being executed, do all registers still keep their values ? does program counter stopped too ? or the power was shut just like I turn it off ? is there anything running stealthily ?
As Rik explained, the CPU doesn't do anything while executing the «hlt» instruction. It stops processing other instructions, until an interrupt wakes the CPU up.
Have a look at page 378 of ftp://download.intel.com/design/Pentium4/manuals/25366614.pdf, it explains exactly what the «hlt» instruction does.
the other question is, what is __builtin_constant_p() called by test_bit()? I can't even find it in the kernel codes.
__builtin_* functions are builtin functions (as their name stands) provided directly by the Gcc compiler. Have a look at http://gcc.gnu.org/onlinedocs/gcc-3.4.3/gcc/Other-Builtins.html for more informations.
Last thing, do not top post please.
Sincerly,
Thomas -- Thomas Petazzoni thomas.petazzoni@xxxxxxxx
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