[U-Boot] [PATCH] ppc: Update README about the new GOT ptr.

Joakim Tjernlund Joakim.Tjernlund at transmode.se
Wed Nov 4 08:44:28 CET 2009


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 744f6bf..bfd9498 100644
--- a/README
+++ b/README
@@ -3916,7 +3916,9 @@ 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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