Hello,
The following issues about FreeRTOS source code were reported to the Renesas’s Japanese user forum of RX MCU. With respect to this kind of these issues, I think that fixing it at the FreeRTOS master source code is better than fixing it at user’s local source code. Can I ask FreeRTOS maintainers to fix it at the FreeRTOS master source code? If possible, what should I do to ask them to fix it?
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In Renesas RX port layer, the SWINTR on-chip peripheral register (byte-size (8-bits width)) is written as byte-size, but it is read back as long-size (32-bits width). The register has to be read back as byte-size.
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Renesas RX MCU pipeline is so smart that only simple reading back from the SWINTR is not enough to wait for the completion of writing to the SWINTR. The operation using the value read has to be executed.
These issues were reported to the following Japanese thread which was started by hirakuni45. And the modified code which was proposed by him in his another post to another site was cited by me to this thread. (Reported code was for the CC-RX compiler but proposed code was for the GNURX compiler.)
Question about FreeRTOS code (Please note that original title and all contents are Japanese.)
https://japan.renesasrulz.com/cafe_rene/f/forum5/5878/freertos/
The code of FreeRTOS Kernel V10.3.1 and our proposal are the following, for example, regarding to the portable/Renesas/RX600v2/portmacro.h file which is one of many Renesas RX’s portmacro.h files. And a screen copy of two pages of RX64M Group User’s Manual is attached.
FreeRTOS Kernel V10.3.1
#pragma inline_asm vPortYield
static void vPortYield( void )
{
/* Save clobbered register - may not actually be necessary if inline asm
functions are considered to use the same rules as function calls by the
compiler. */
PUSH.L R5
/* Set ITU SWINTR. */
MOV.L #553696, R5 ----> 553696 = 872E0H
MOV.B #1, [R5]
/* Read back to ensure the value is taken before proceeding. */
MOV.L [R5], R5 <---- HERE!
/* Restore clobbered register to its previous value. */
POP R5
}
Proposal
#pragma inline_asm vPortYield
static void vPortYield( void )
{
/* Save clobbered register - may not actually be necessary if inline asm
functions are considered to use the same rules as function calls by the
compiler. */
PUSH.L R5
/* Set ITU SWINTR. */
MOV.L #553696, R5
MOV.B #1, [R5]
/* Read back to ensure the value is taken before proceeding. */
CMP [R5].UB, R5 <---- HERE!
/* Restore clobbered register to its previous value. */
POP R5
}
RX64M Group User’s Manual: Hardware
https://www.renesas.com/us/en/search/keyword-search.html#genre=document&q=r01uh0377
r01uh0377ej0110-rx64m.pdf
