Hello Dashi Cao, On Tue, 20 Jan 2015 14:12:35 +0800, Da Shi Cao <dscao...@gmail.com> wrote: > In standalone applications, it seems that the execution of printf > function in U-Boot is dependent on the value of register R9, which is > setup in app_startup. But r9 can be used by your program at the > decision of gcc compilation which is not aware of this dependence. > This is especially the case if +O2 is used!
U-Boot follows the ARM EABI, in which ""The role of register r9 is platform specific". In U-Boot r9 is specifically used for the global data structure, and the standalone programs must follow this EABI. If your standalone program is built with the same options as U-Boot example standalone programs are (see hellow_world), then it should have gcc option -ffixed-r9 which will prevent the compiler from ever touching r9. How exactly do you build your standalone application? > My version is U-Boot 2014.10 > > Regards, > Dashi Cao Amicalement, -- Albert. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
