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Purpose of SSI and SWI ?

Posted by simointe on November 17, 2016

(TMS570) Hello, In the doc, it is said: « FreeRTOS requires exclusive use of RTI channel 0, SWI instructions, and System Software Interrupt (SSI) 0 ». I understand for the RTI of course, but what is the purpose of SWI and SSI ?

Purpose of SSI and SWI ?

Posted by edwards3 on November 17, 2016

Greping for SWI I see #pragma SWI_ALIAS( vPortYield, 0 ) so SWI is used for yield.

Greping for SSI I see #define portYIELDWITHINAPI() { portSYSSSIR1REG = portSYSSSIR1SSKEY; asm( " DSB " ); asm( " ISB " ); } and #define portYIELDFROMISR( x ) if( x != pdFALSE ){ portSYSSSIR1REG = portSYSSSIR1SSKEY; ( void ) portSYSSSIR1REG; } so this is also used for yielding. So it looks like an application yield is using SWI and RTOS yield is using SSI.

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