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| author | Daniel Schwierzeck <daniel.schwierzeck@gmail.com> | 2013-02-12 22:22:13 +0100 |
|---|---|---|
| committer | Daniel Schwierzeck <daniel.schwierzeck@gmail.com> | 2013-02-12 22:22:13 +0100 |
| commit | 696a3b2a5368360c149335e2a35b8900a78f47fa (patch) | |
| tree | ebad9e8ee6bfd035c5b9b10a965ae77f129df305 /arch/mips/cpu/mips32 | |
| parent | eea8a320e1299cbd76d3ffd9a1fe0e0d3313268b (diff) | |
| download | u-boot-imx-696a3b2a5368360c149335e2a35b8900a78f47fa.zip u-boot-imx-696a3b2a5368360c149335e2a35b8900a78f47fa.tar.gz u-boot-imx-696a3b2a5368360c149335e2a35b8900a78f47fa.tar.bz2 | |
MIPS: start.S: optimize BSS initialization
Get the start and end address for clearing BSS from the newly
introduced symbols __bss_start and __bss_end. After GOT is
relocated, those symbols are already pointing to the correct
addresses.
Also optimize the loop by moving the address incrementation
to the delay slot to avoid the initial sub instruction.
Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Diffstat (limited to 'arch/mips/cpu/mips32')
| -rw-r--r-- | arch/mips/cpu/mips32/start.S | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/arch/mips/cpu/mips32/start.S b/arch/mips/cpu/mips32/start.S index 7373d4e..cd8b914 100644 --- a/arch/mips/cpu/mips32/start.S +++ b/arch/mips/cpu/mips32/start.S @@ -228,17 +228,19 @@ in_ram: blt t2, t3, 1b addi t4, 4 - /* Clear BSS */ - lw t1, -12(t0) # t1 <-- uboot_end_data - lw t2, -8(t0) # t2 <-- uboot_end - add t1, s1 # adjust pointers - add t2, s1 + /* + * Clear BSS + * + * GOT is now relocated. Thus __bss_start and __bss_end can be + * accessed directly via $gp. + */ + la t1, __bss_start # t1 <-- __bss_start + la t2, __bss_end # t2 <-- __bss_end - sub t1, 4 1: - addi t1, 4 - bltl t1, t2, 1b - sw zero, 0(t1) + sw zero, 0(t1) + blt t1, t2, 1b + addi t1, 4 move a0, s0 # a0 <-- gd la t9, board_init_r |