Jithu Joseph authored Mar 14, 2014 and Vikram Narayanan committed Oct 25, 2016

The previous variable argument approch for printf based on 32bit XV6 was not working, as the first 6 integer arguments are passed in registers and merely incrementing the sp++ wont fetch subsequent arguments when compiled for 64 bit. changed this to to use builtin va_* macros. Now able to print multiple integers.

Suspecting some issues in loading - see the description of commented printint. This needs to be analysed. (an alternate approch is working is added for time-being)