diff options
| author | Peter Marheine <pmarheine@chromium.org> | 2022-08-18 14:39:00 +1000 |
|---|---|---|
| committer | Chromeos LUCI <chromeos-scoped@luci-project-accounts.iam.gserviceaccount.com> | 2022-08-24 04:03:50 +0000 |
| commit | 94e0ef35c576b88ac8fb3802ca063da0689516ce (patch) | |
| tree | 7797b987a639088f36d23320ef2e7e42588e3a08 | |
| parent | cde4d531330a263256787a9e91681d208675a896 (diff) | |
| download | chrome-ec-94e0ef35c576b88ac8fb3802ca063da0689516ce.tar.gz | |
nissa/ite: enable FPU
Given an appropriately-configured toolchain, IT8xxx2 can enable FPU even
without integer multiply support enabled in the ISA. Use of floating-point
significantly reduces the instruction count for hot paths in motion sensor
code, which should in turn reduce instruction cache pressure and improve
performance. Performance improvement for code that is switched to use
floating-point is about 10%.
Overall code size is slightly increased by this change as a few support
functions are now added, but by inspection motionsense code no longer
contains calls to functions like __udivdi3 for 64-bit arithmetic, which
are extremely large (__udivdi3 is 1108 bytes of code, more than a quarter
of the IT8xxx2 instruction cache). By experiment, overall system
performance is improved significantly with reduced code size.
BUG=b:240485526,b:227961840
TEST=Nereid EC is much more stable than before when the gyroscope is
enabled with `accelrate 2 100000`.
BRANCH=none
Cq-Depend: chromium:3828780
Change-Id: I88672eef39ccab115fe07a9415468ff455def112
Signed-off-by: Peter Marheine <pmarheine@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3840987
Reviewed-by: Andrew McRae <amcrae@google.com>
| -rw-r--r-- | zephyr/projects/nissa/joxer/prj.conf | 3 | ||||
| -rw-r--r-- | zephyr/projects/nissa/nereid/prj.conf | 3 |
2 files changed, 6 insertions, 0 deletions
diff --git a/zephyr/projects/nissa/joxer/prj.conf b/zephyr/projects/nissa/joxer/prj.conf index 714ac28d5e..c3b39b0424 100644 --- a/zephyr/projects/nissa/joxer/prj.conf +++ b/zephyr/projects/nissa/joxer/prj.conf @@ -7,6 +7,9 @@ CONFIG_BOARD_JOXER=y CONFIG_CROS_FLASH_IT8XXX2=y CONFIG_CROS_SYSTEM_IT8XXX2=y CONFIG_ESPI_IT8XXX2=y +CONFIG_FPU=y +# rv32iafc/ilp32f is not supported by the toolchain, so use soft-float +CONFIG_FLOAT_HARD=n CONFIG_TACH_IT8XXX2=y # Allow more time for the charger to stabilise diff --git a/zephyr/projects/nissa/nereid/prj.conf b/zephyr/projects/nissa/nereid/prj.conf index 18ebc494dd..9cafe43216 100644 --- a/zephyr/projects/nissa/nereid/prj.conf +++ b/zephyr/projects/nissa/nereid/prj.conf @@ -7,6 +7,9 @@ CONFIG_BOARD_NEREID=y CONFIG_CROS_FLASH_IT8XXX2=y CONFIG_CROS_SYSTEM_IT8XXX2=y CONFIG_ESPI_IT8XXX2=y +CONFIG_FPU=y +# rv32iafc/ilp32f is not supported by the toolchain, so use soft-float +CONFIG_FLOAT_HARD=n # Allow more time for the charger to stabilise CONFIG_PLATFORM_EC_POWER_BUTTON_INIT_TIMEOUT=5 |