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firmware: Minor optimization in _scratch_init() 

Before entering _scratch_init(), register t3 already holds a copy
of the firmware end address, hence there is no need to calculate
it again. This reduces 3 instructions in each _scratch_init() loop.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
This commit is contained in:
Bin Meng 2021-07-10 22:00:31 +08:00 committed by Anup Patel
parent 0e12aa8dee
commit 14c7f71c0d
1 changed files with 9 additions and 4 deletions
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13
firmware/fw_base.S
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@ -278,6 +278,14 @@ _bss_zero:
/* hartid 0 is mandated by ISA */
li t1, 0
_scratch_init:
/*
* The following registers hold values that are computed before
* entering this block, and should remain unchanged.
*
* t3 -> the firmware end address
* s7 -> HART count
* s8 -> HART stack size
*/
add tp, t3, zero
mul a5, s8, t1
sub tp, tp, a5
@ -287,10 +295,7 @@ _scratch_init:
/* Initialize scratch space */
/* Store fw_start and fw_size in scratch space */
lla a4, _fw_start
lla a5, _fw_end
mul t0, s7, s8
add a5, a5, t0
sub a5, a5, a4
sub a5, t3, a4
REG_S a4, SBI_SCRATCH_FW_START_OFFSET(tp)
REG_S a5, SBI_SCRATCH_FW_SIZE_OFFSET(tp)
/* Store next arg1 in scratch space */