Hi Enoch, since you asked for comments ...
On 02/13/2013 05:38 AM, Enoch wrote: > Hello Matthias and all, > > I'd like to see this forum also offering code snippets, so here's my > first humble attempt of harnessing the atomic bit manipulation > instructions. > > : port:hi ( portadr bitno -- ) \ SBI > swap $20 - 3 lshift or $9A00 or code , end-code > ; > > : port:lo ( portadr bitno -- ) \ CBI > swap $20 - 3 lshift or $9800 or code , end-code > ; > > example: > > PORTB 7 port:hi green.hi > PORTB 7 port:lo green.lo > So you want to set or clear a bit in some register. What is wrong with the words found in bitnames.frt? include lib/bitnames.frt PORTB 7 portpin: green and later green pin_output green high \ do something here green low Sure, bitnames is doing read+modify+write on the memory mapped location of the register, while your solution uses sbi/cbi which does not work on the memory mapped location (hence $20 - ). But what exactly is better with using sbi/cbi? That sbi/cbi cannot be interrupted once the instruction is executing? But all the instructions leading up to the sbi/cbi can be interrupted, can't they? Do I miss the entire motivation of the code snippet? Would you dare to enlighten me?? As Matthias pointed out elsewhere: your snippet is intersting, because assembly instructions are coded in at compile time without loading the full assembler. That I can see. Cheers, Erich ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb _______________________________________________ Amforth-devel mailing list for http://amforth.sf.net/ Amforth-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/amforth-devel
