diff options
| author | Bin Meng <bmeng.cn@gmail.com> | 2021-07-10 17:00:31 +0300 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2021-07-11 09:11:50 +0300 |
| commit | 14c7f71c0da641ece1b91ef0bde190f66c980a3e (patch) | |
| tree | 262d89849c3faf6de46ff0e111bfe1c98c9c5f67 /firmware | |
| parent | 0e12aa8dee632f67dbb458aa5d3ee38f7db4e70c (diff) | |
| download | opensbi-14c7f71c0da641ece1b91ef0bde190f66c980a3e.tar.xz | |
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>
Diffstat (limited to 'firmware')
| -rw-r--r-- | firmware/fw_base.S | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/firmware/fw_base.S b/firmware/fw_base.S index a5ce946..8e40562 100644 --- a/firmware/fw_base.S +++ b/firmware/fw_base.S @@ -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 */ |