HelenOS sources

SHIFT             154 kernel/arch/amd64/src/drivers/i8254.c 	delay(1 << SHIFT);
SHIFT             157 kernel/arch/amd64/src/drivers/i8254.c 	CPU->frequency_mhz = (clk2 - clk1) >> SHIFT;
SHIFT             154 kernel/arch/ia32/src/drivers/i8254.c 	delay(1 << SHIFT);
SHIFT             157 kernel/arch/ia32/src/drivers/i8254.c 	CPU->frequency_mhz = (clk2 - clk1) >> SHIFT;
HelenOS homepage, sources at GitHub