pin-access voodoo

[orgua]

Hi paul,

i'm writing a lib to emulate several onewire-slaves. some parts (platform-dependency) share code with this lib. i noticed a lot of legacy Studt-code, wanted to do a cleanup and have two questions for now:

• is there any reason for local pin_mask / pin_reg in every pin-accessing function? The ASM-Code is not really needed anymore on AVR and it works fine by directly using the private class-variables baseReg and bitmask.

IO_REG_TYPE mask = bitmask;
volatile IO_REG_TYPE *reg IO_REG_ASM = baseReg;

• same for the disabled interrupt. these operations do not need to be atomic and it works fine without it. or am i wrong?

noInterrupts();
DIRECT_WRITE_LOW(reg, mask);
DIRECT_MODE_OUTPUT(reg, mask);  // drive output low
interrupts();

There are some more points that could be optimized. but one step after the other. i am happy to supply some pullrequests.