MIPS: start.S: simplify relocation offset calculation
The current code uses four instructions and a
temporary register to calculate the relocation
offset and to adjust the gp register.
The relocation offset can be calculated directly
from the CONFIG_SYS_MONITOR_BASE constant and from
the destination address. The resulting offset can
be used to adjust the gp pointer.
This approach makes the code a bit simpler because
it needs two instructions only.
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Daniel Schwierzeck <daniel.schwierzeck@googlemail.com>
diff --git a/arch/mips/cpu/mips32/start.S b/arch/mips/cpu/mips32/start.S
index 64a606f..d67dafa 100644
--- a/arch/mips/cpu/mips32/start.S
+++ b/arch/mips/cpu/mips32/start.S
@@ -283,19 +283,13 @@
move s2, a2 # save destination address in s2
li t0, CONFIG_SYS_MONITOR_BASE
+ sub s1, s2, t0 # s1 <-- relocation offset
+
la t3, in_ram
lw t2, -12(t3) # t2 <-- uboot_end_data
move t1, a2
- /*
- * Fix $gp:
- *
- * New $gp = (Old $gp - CONFIG_SYS_MONITOR_BASE) + Destination Address
- */
- move t6, gp
- sub gp, CONFIG_SYS_MONITOR_BASE
- add gp, a2 # gp now adjusted
- sub s1, gp, t6 # s1 <-- relocation offset
+ add gp, s1 # adjust gp
/*
* t0 = source address
diff --git a/arch/mips/cpu/mips64/start.S b/arch/mips/cpu/mips64/start.S
index 3c0f1c3..d213c8e 100644
--- a/arch/mips/cpu/mips64/start.S
+++ b/arch/mips/cpu/mips64/start.S
@@ -162,19 +162,13 @@
move s2, a2 # save destination address in s2
dli t0, CONFIG_SYS_MONITOR_BASE
+ dsub s1, s2, t0 # s1 <-- relocation offset
+
dla t3, in_ram
ld t2, -24(t3) # t2 <-- uboot_end_data
move t1, a2
- /*
- * Fix $gp:
- *
- * New $gp = (Old $gp - CONFIG_SYS_MONITOR_BASE) + Destination Address
- */
- move t8, gp
- dsub gp, CONFIG_SYS_MONITOR_BASE
- dadd gp, a2 # gp now adjusted
- dsub s1, gp, t8 # s1 <-- relocation offset
+ dadd gp, s1 # adjust gp
/*
* t0 = source address