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authorWolfgang Denk <wd@denx.de>2010-05-28 20:34:39 +0200
committerWolfgang Denk <wd@denx.de>2010-05-28 20:34:39 +0200
commitbd7bb6f8a3278caff0ac6eeaf08b188b9bb05dfc (patch)
tree8c0d3886a19dfd82551588928b448198ac5274ce /README
parent35269d3fca60b5f73113b0443c8e40070749c1d9 (diff)
parent1117cbf2adac59050af1751af6c6a524afa5c3ef (diff)
Merge branch 'next' of git://git.denx.de/u-boot-nios
Diffstat (limited to 'README')
-rw-r--r--README15
1 files changed, 10 insertions, 5 deletions
diff --git a/README b/README
index 81692c0a49..68f1720ec7 100644
--- a/README
+++ b/README
@@ -177,9 +177,6 @@ Directory Hierarchy:
/mips Files generic to MIPS architecture
/cpu CPU specific files
/lib Architecture specific library files
- /nios Files generic to Altera NIOS architecture
- /cpu CPU specific files
- /lib Architecture specific library files
/nios2 Files generic to Altera NIOS2 architecture
/cpu CPU specific files
/lib Architecture specific library files
@@ -3337,8 +3334,8 @@ details; basically, the header defines the following image properties:
Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
INTEGRITY).
* Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
- IA64, MIPS, NIOS, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
- Currently supported: ARM, AVR32, Intel x86, MIPS, NIOS, PowerPC).
+ IA64, MIPS, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
+ Currently supported: ARM, AVR32, Intel x86, MIPS, Nios II, PowerPC).
* Compression Type (uncompressed, gzip, bzip2)
* Load Address
* Entry Point
@@ -4023,6 +4020,14 @@ On ARM, the following registers are used:
==> U-Boot will use R8 to hold a pointer to the global data
+On Nios II, the ABI is documented here:
+ http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
+
+ ==> U-Boot will use gp to hold a pointer to the global data
+
+ Note: on Nios II, we give "-G0" option to gcc and don't use gp
+ to access small data sections, so gp is free.
+
NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
or current versions of GCC may "optimize" the code too much.