Comments (5)
Thanks. You are right, there is a bug there.
I think a better way would be to cast the subtraction result to a signed type,
if ((int32_t) (now - led->off_until) >= 0)
a bit similar to what you did but IMO a bit cleaner.
but also need to guarantee that off_until
is never set to more than INT32_MAX in the future (25 days), which should be straightforward to enforce.
from candlelight_fw.
Yes, wrap around happens. This is a common occurrence in the Linux kernel and even must be considered for transient time values spanning years -- a Linux machine might be up for that long! In such cases, it's better to just think of the counter/timer value as meaningless until compared (via subtraction) to a target time/count and, as @fenugrec illustrated, treat them as signed values -- only worry about the difference, and you'll stay out of trouble.
Also, signed math is far fewer instructions. You just have to change the way you are thinking about your timers and time values.
from candlelight_fw.
yes. Will fix when I get a chance; leaving this open as a reminder
from candlelight_fw.
I cobbled up a fix (no time to test on hardware yet but compiles) in PR #78 , if anyone would like to review / test
from candlelight_fw.
Updated the fix in #78, and tested on hardware. Looks fine, but feedback would be appreciated.
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Related Issues (20)
- RFC: cmake-presets to select included toolchain file by default ?
- tweak `atexit` to get rid of malloc HOT 2
- RFC : empty fifos + hardware mailboxes when re-enabling CAN ? HOT 6
- startup.c is broken - hardfault with large BSS HOT 8
- While loops in USB ISR HOT 7
- Feature: add support for `GS_CAN_FEATURE_GET_STATE` and `GS_CAN_FEATURE_BERR_REPORTING` HOT 5
- build warning: "_close is not implemented and will always fail" HOT 2
- Canable device hangs after desktop application crash (= stop without disonnecting) HOT 25
- cansequence tool shows wrong telegram order HOT 19
- Clear internal data structures holding unsent frames HOT 1
- Openmoko firmware upgrade , no jumper to enter DFU mode or button HOT 21
- About candlelight and Cangaroo HOT 2
- version for stm32F042C4xx? HOT 7
- No Can Frames recieved after device reset without a power cycle. candleLight Firmware. HOT 7
- CandleLight FD at 8 Mbps HOT 3
- CPU_FAMILY STM32G0B1XK vs. CPU_FAMILY STM32G0B1XE (not comprehensible for rookies) HOT 4
- Potential firmware / driver issue HOT 21
- Problem building firmware for STM32G0B1 HOT 11
- Problem ACK on tx error HOT 1
- CANable-MKS problem HOT 1
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