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-rw-r--r--README9
1 files changed, 7 insertions, 2 deletions
diff --git a/README b/README
index a5ffbb5..491397a 100644
--- a/README
+++ b/README
@@ -3499,7 +3499,7 @@ GCC's implementation.
For PowerPC, the following registers have specific use:
R1: stack pointer
- R2: TOC pointer
+ R2: reserved for system use
R3-R4: parameter passing and return values
R5-R10: parameter passing
R13: small data area pointer
@@ -3508,7 +3508,7 @@ For PowerPC, the following registers have specific use:
(U-Boot also uses R14 as internal GOT pointer.)
- ==> U-Boot will use R29 to hold a pointer to the global data
+ ==> U-Boot will use R2 to hold a pointer to the global data
Note: on PPC, we could use a static initializer (since the
address of the global data structure is known at compile time),
@@ -3517,6 +3517,11 @@ For PowerPC, the following registers have specific use:
average for all boards 752 bytes for the whole U-Boot image,
624 text + 127 data).
+On Blackfin, the normal C ABI (except for P5) is followed as documented here:
+ http://docs.blackfin.uclinux.org/doku.php?id=application_binary_interface
+
+ ==> U-Boot will use P5 to hold a pointer to the global data
+
On ARM, the following registers are used:
R0: function argument word/integer result