Hi Paul, one of the reasons why bitfields have been abandoned is that bitfields are quite ineffective regarding hardware registers. If you have a register that contains various configuration bits, accessing the individual bits through a bitfield results in one separate RMSW (read-mask-set-write) operation for each and every access, which is by magnitudes larger and faster than a single combined access, which usually is one single instruction. Since registers are declared volatile, the compiler cannot combine bitfield accesses into one operation. Each assignment must be one access exactly as written.
Also, in some situations, more than one bit/multibit setting needs to be set simultaneously. which is impossible if you use bitfields. Not to mention the additional confusion with the predefined symbols: do they relate to the bitfield (0..3) or the register (maybe 0x00..0x60 with 0x60 as mask) So removing the bitfields was (not only) an educational step, forcing people to program efficiently and not conveniently on a microcontroller. :) JMGross ----- Ursprüngliche Nachricht ----- Von: Paul Voith Gesendet am: 16 Jul 2012 08:28:07 Hi all, I am trying to port code from an earlier release of msp430-gcc and having trouble. Specifically now that <io.h> is depreciated I don't know the expected mechanism to support the "port1.out.pin0" nomenclature for referencing bit I/O. In the past there was an installation kit for the tool chain on windows. I see now that there is a built zip file for windows (Thanks Matthias!). Any info available on how to install this? Perhaps just unzip into a searchable directory is all? The have referred to the manual but it seems out of date for these aspects. Thanks -- Paul ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Mspgcc-users mailing list Mspgcc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mspgcc-users
