From 0df01fd3d71481b5cc7aeea6a741b9fc3be15178 Mon Sep 17 00:00:00 2001 From: Thomas Chou Date: Fri, 21 May 2010 11:08:03 +0800 Subject: nios2: fix r15 issue for gcc4 The "-ffixed-r15" option doesn't work well for gcc4. Since we don't use gp for small data with option "-G0", we can use gp as global data pointer. This allows compiler to use r15. It is necessary for gcc4 to work properly. Signed-off-by: Thomas Chou Signed-off-by: Scott McNutt --- doc/README.standalone | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'doc') diff --git a/doc/README.standalone b/doc/README.standalone index 885c92f..6381087 100644 --- a/doc/README.standalone +++ b/doc/README.standalone @@ -19,12 +19,12 @@ Design Notes on Exporting U-Boot Functions to Standalone Applications: thus the compiler cannot perform type checks on these assignments. 2. The pointer to the jump table is passed to the application in a - machine-dependent way. PowerPC, ARM, MIPS and Blackfin architectures - use a dedicated register to hold the pointer to the 'global_data' - structure: r2 on PowerPC, r8 on ARM, k0 on MIPS, and P3 on Blackfin. - The x86 architecture does not use such a register; instead, the - pointer to the 'global_data' structure is passed as 'argv[-1]' - pointer. + machine-dependent way. PowerPC, ARM, MIPS, Blackfin and Nios II + architectures use a dedicated register to hold the pointer to the + 'global_data' structure: r2 on PowerPC, r8 on ARM, k0 on MIPS, + P3 on Blackfin and gp on Nios II. The x86 architecture does not + use such a register; instead, the pointer to the 'global_data' + structure is passed as 'argv[-1]' pointer. The application can access the 'global_data' structure in the same way as U-Boot does: @@ -56,6 +56,7 @@ Design Notes on Exporting U-Boot Functions to Standalone Applications: ARM 0x0c100000 0x0c100000 MIPS 0x80200000 0x80200000 Blackfin 0x00001000 0x00001000 + Nios II 0x02000000 0x02000000 For example, the "hello world" application may be loaded and executed on a PowerPC board with the following commands: -- cgit v1.1