On Monday 08 June 2009 21:35:05 matthieu castet wrote: > Michael Buesch wrote: > > On Sunday 07 June 2009 11:28:50 matthieu castet wrote: > >> Hi, > >> > >> I wonder with openwrt for bcm47xx is not build with "-msoft-float". > >> The cpu doesn't have fpu and the current floating code get emulated by the > >> kernel emulator instead of using the gcc emulation support (that is cheaper > >> because there is no kernel trap). > > > > Well, I guess on a typical bcm47xx setup there's hardly any application > > that uses > > floating point math. > note that dropbear seems to use some, but that not critical. > > > Does -msoft-float increase the binary/image size? If so, I'd > > vote for _not_ adding -msoft-float. If it doesn't make a size difference, > > we should > > probably add it. > > > That shouldn't increase size of application that don't use float. > I did a quick test with dropbear that contain very few float. > Here are the results (sfloat means -msoft-float, sgcc mean -shared-libgcc) > > > $size /tmp/dropbear* > text data bss dec hex filename > 226924 4252 1744 232920 38dd8 /tmp/dropbear > 234719 4328 1744 240791 3ac97 /tmp/dropbear_sfloat > 220781 4192 1744 226717 3759d /tmp/dropbear_sfloat_sgcc > 219956 4152 1744 225852 3723c /tmp/dropbear_sgcc > > As you can see with a static libgcc the size of the softfloat binary > increase (8k) because all float emulation code is duplicated in the binary. > With a shared libgcc the softfloat binary is smaller, the increase size > is less than 1k. > > I don't know the impact for whole binary. I should try to build a > typical bcm47xx setup and see the impact.
Ok. It still smells like we're trying to solve a problem that does not exist. Is the performance of any app increased in real life? -- Greetings, Michael. _______________________________________________ openwrt-devel mailing list openwrt-devel@lists.openwrt.org https://lists.openwrt.org/mailman/listinfo/openwrt-devel
