[U-Boot] [PATCH 4/4] ppc: Update README about the new GOT ptr.
Joakim Tjernlund
Joakim.Tjernlund at transmode.se
Tue Jan 19 14:41:58 CET 2010
r14 is no longer used as non volatile GOT ptr. Instead
the volatile r12 is used so be sure to do GET_GOT in
asm code when you need to access global data.
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund at transmode.se>
---
README | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/README b/README
index 7affe10..263bb05 100644
--- a/README
+++ b/README
@@ -3922,7 +3922,9 @@ For PowerPC, the following registers have specific use:
R30: GOT pointer
R31: frame pointer
- (U-Boot also uses R14 as internal GOT pointer.)
+ (U-Boot also uses R12 as internal GOT pointer. r12
+ is a volatile register so r12 needs to be reset when
+ going back and forth between asm and C)
==> U-Boot will use R2 to hold a pointer to the global data
--
1.6.4.4
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