I am trying to play music on a 200Mhz ARM9 processor. I know it can do it, because madplay works on the board already and it sounds great. I want to create a frontend so I can play playlists and also so I can use an LCD that's attached to the board. Madplay is a bad choice as a backend, because it is designed to take input directly from tty instead of stdin (or something like that...you don't need to hit enter at the end of a command anyway).

The second obvious choice is mpg321, because it has a remote mode especially made for frontends. Also, it claims that all calculations are in fixed point because it uses the MAD library. Well, turns out that there are about 2 floating point calculations in the program (not in MAD)...per frame. Songs sound terrible as a result. I tried to take out the floating points, granted I didn't try too hard, but the program seems to really need the 2 calculations to be doubles.

Anyway...
I need a media player that must:
run from the command line
play mp3s
be very light (200 mhz, 32 MB ram is all I have)
not use any floating point numbers (or very few infrequently).

Any suggestions?

mplayer can run by the command line because that is what it is designed to run from. You can use stdin to contol it. Another program (actually a library) is xine-lib. You have to make a user interface like a CLI or even better the ncurse to handle it. Use LAME mp3 decoder instead of mpg321. These programs should be able to compile on a ARM chip.

Try edit the code so the double converts to float point instead of the floating point converting to double.

You can try to include -msoft-float for CFLAGS and CXXFLAGS. It will implement floating point emulation instead of doing the real thing from the hardware.