Am Montag, den 24.12.2018, 17:51 +0000 schrieb Jan Kromhout: > Hello, > > I wont to write my own routine in assembler as a learning goal. > Have looked into a lot of asm routines, but can’t figure out how to > add two doubles into R16 to R23 > and after the calculation put R16 to R19 back to the stack. > > Can I use R16 to R19 freely for my own use, or should I take another > set. > > The calculation between is no problem. > > Please can someone help me out with this, > and any help is appriciated!
The registers that are free to use in own assembly words are documented here: http://amforth.sourceforge.net/TG/AVR8.html#register-mapping The mapping between the temp-Names and the actual registers can be found at avr8/macros.asm. If you want to go deep into the assembler programming, esp. within amforth, I'd strongly recommend, that you study the code very carefully. It contains optimizations and macros that are not trivially to understand. Adding two double numbers (that is 2x4 avr registers) is more on the trivial side however. look at words/d-plus.asm. Matthias _______________________________________________ Amforth-devel mailing list for http://amforth.sf.net/ Amforth-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/amforth-devel
