http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48602
--- Comment #41 from Thomas Henlich <thenlich at users dot sourceforge.net> 2011-04-21 16:36:14 UTC --- Actually it may be even simpler than that: We already know how many significant digits (d) we want in the output string, and at what digit to round. So we can write the digits of the significand into a buffer (with Ew.d editing). All that would remain is to decide whether to print the exponent or not (according to a simple integer comparison), otherwise shift the decimal point to the right place (simple string operation). E.g. 0.0995 with RU,G0.2 dtoa -> ".10", exponent=0 output -> ".10" 12345000 with RD,G0.4: dtoa -> ".1234", exponent=8 output -> ".1234E+08" because exponent > d 12345678.95 with RD,G0.9: dtoa -> ".123456789", exponent=8 output -> "123456789." because exponent < d
