[avr-gcc-list] Double desirability

[James A.R. Koehler]

   I just want to put in my two-cents worth in support of having a 
decent double library for the AVR.  Doubles are not just useful in 
desktop machines but also are required more and more frequently in 
embedded systems.  I do RF design and most, perhaps all, modern DDS 
(direct digital sysnthesis) chips have 48-bit (often larger!) phase 
registers and so to set frequencies, one must be able to do 64-bit 
operations.

   A few years ago, I wrote a program using one of these DDS chips in 
AVR-GCC and was astonished to see that the code size went up enormously 
in integer operations when I went from 32-bit variables to 64-bit ones.  
I eventually wrote my own small library to do 64-bit integer multiplies 
and divides.  I don't know if the current library routines are any 
better.  In terms of program size, a 64-bit multiply or divide shouldn't 
take significantly more code space than a 32-bit one - it will just run 
a factor of two slower.

   I don't know much about compiler design but if there is any way I 
can help in producing these libraries, I'd be delighted to do so.

   Jim