[U-Boot] printf in u-boot cannot support %f

Hi, The codes below: ... double result1 = 3.14; printf("result1:%f\n", result1);// error .... turn out: result1:%f How can I get the correct result? Thanks a lot! The U-boot version is: => ver U-Boot 2008.10 (Jul 15 2009 - 21:56:05) MPC512X I wan to a little more complex program in standalone mode in u-boot. Is it possilbe to port g-libc to u-boot standalone mode? Tanks. Best regards, Michael Franklin