Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem


Zynq Port Tick Handler Signature

Posted by razed11 on October 2, 2015

The tick handler is defined as

~~~~ void FreeRTOSTickHandler( void ) ~~~~

It is given a callback reference (&xTimer).

~~~~ xStatus = XScuGicConnect( &xInterruptController, XPARSCUTIMERINTR, (XilExceptionHandler) FreeRTOSTickHandler, ( void * ) &xTimer ); ~~~~

The application IRQ handler calls it as:

~~~~ pxVectorEntry->Handler( pxVectorEntry->CallBackRef ); ~~~~

Should we address this?

Zynq Port Tick Handler Signature

Posted by rtel on October 3, 2015

This was a deliberate decision and considered quite benign as the tick handler is povided by the RTOS, and it does not use the parameter. The only time the compiler will match the prototype of the FreeRTOSTickHandler() function and the prototype of the function passed into XScuGicConnect() is when XScuGicConnect() is itself called - which again is taken care of in the RTOS code.

The line pxVectorEntry->Handler( pxVectorEntry->CallBackRef ); will place a value in register R0, but the function FreeRTOSTickHandler( void ) will never use the value from the register. The alternative is to have FreeRTOSTickHandler( void ) accept a parameter, then use the parameter [as in ( void ) parameter] to avoid compilier warnings, and potentially generate more code if the optimisation level is 0.


Zynq Port Tick Handler Signature

Posted by razed11 on October 5, 2015

Right. R0 is probably stacked so a void (*)(void) method that might make use of that register would not be doing any harm either. I very much doubt that the hard float ABI is different in this regard.

[ Back to the top ]    [ About FreeRTOS ]    [ Sitemap ]    [ ]

Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.

Latest News

Meet us at Embedded World. Hall 3A-525.

Hear from Richard Barry at Embedded World. Feb 28, 16:00, Hall 4-428.

Video: Watch James Gosling & Richard Barry at re:Invent, Las Vegas 2017.

FreeRTOS kernel V10.0.1 is available for immediate download. Now MIT licensed.

FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

IAR Partner

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers

STMicro RTOS partner supporting ARM7, ARM Cortex-M3, ARM Cortex-M4 and ARM Cortex-M0

Texas Instruments MCU Developer Network RTOS partner for ARM and MSP430 microcontrollers

OpenRTOS and SafeRTOS