diff options
author | Thomas Chou <thomas@wytron.com.tw> | 2010-05-21 07:08:03 +0400 |
---|---|---|
committer | Scott McNutt <smcnutt@psyent.com> | 2010-05-28 18:56:03 +0400 |
commit | 0df01fd3d71481b5cc7aeea6a741b9fc3be15178 (patch) | |
tree | a5eb637453d7f400eb1f9709b376ad247905e265 /doc | |
parent | 661ba14051db6766932fcb50ba1ec7c67f230054 (diff) | |
download | u-boot-0df01fd3d71481b5cc7aeea6a741b9fc3be15178.tar.xz |
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 <thomas@wytron.com.tw>
Signed-off-by: Scott McNutt <smcnutt@psyent.com>
Diffstat (limited to 'doc')
-rw-r--r-- | doc/README.standalone | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/doc/README.standalone b/doc/README.standalone index 885c92fb3a..6381087493 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: |