# Requesting Freertos port code to CR-(4) series **URL:** \ **Category:** Kernel\ **Created:** [March 14, 2025, 12:10pm UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731 "2025-03-14T12:10:46Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [March 14, 2025, 12:10pm UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/1 "2025-03-14T12:10:46Z")
Hi FreeRtos Team, Is there any reference Freertos port code to CR-(4) series starup-cr4.s file and loader file. Need startup.s file with details of all interupts related to scheduling and systick interupt handlers? also need to have stack pointed initialization code with memory details in it. If any port code of FreeRtos with example would be great help ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [March 16, 2025, 5:00pm UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/2 "2025-03-16T17:00:16Z")
You should be able to use the CRx port: - Use the following if you do not want to use MPU - [FreeRTOS-Kernel/portable/GCC/ARM\_CRx\_No\_GIC at main · FreeRTOS/FreeRTOS-Kernel · GitHub](https://github.com/FreeRTOS/FreeRTOS-Kernel/tree/main/portable/GCC/ARM_CRx_No_GIC). Corresponding demo: [FreeRTOS/FreeRTOS/Demo/CORTEX\_No\_GIC\_R5F\_TI\_RM57\_HERCULES\_GCC at main · FreeRTOS/FreeRTOS · GitHub](https://github.com/FreeRTOS/FreeRTOS/tree/main/FreeRTOS/Demo/CORTEX_No_GIC_R5F_TI_RM57_HERCULES_GCC). - Use the following if you want to use MPU - [FreeRTOS-Kernel/portable/GCC/ARM\_CRx\_MPU at main · FreeRTOS/FreeRTOS-Kernel · GitHub](https://github.com/FreeRTOS/FreeRTOS-Kernel/tree/main/portable/GCC/ARM_CRx_MPU). Corresponding demo: [FreeRTOS/FreeRTOS/Demo/CORTEX\_MPU\_R5F\_TI\_RM57\_HERCULES\_GCC at main · FreeRTOS/FreeRTOS · GitHub](https://github.com/FreeRTOS/FreeRTOS/tree/main/FreeRTOS/Demo/CORTEX_MPU_R5F_TI_RM57_HERCULES_GCC). ---
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [March 17, 2025, 1:09pm UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/3 "2025-03-17T13:09:05Z")
Hi Gaurav, Thanks for the response, In shared code of portasm.s file, it doesn’t contain details of Vector table changes for scheduler, timers. I was looking for some assembly startup code containing below things:- 1. ResetHandler(Tr\_Reset) api calling main application 2. Also having interrupt vector table with below changes, as i heard that default scheduler api’s doesn’t help in scheduling and starting of newly created task. a) Make default system scheduler handler to be replaced to FreeRtos scheduler api(FreeRTOS\_IRQ\_Handler, FreeRTOS\_SVC\_Handler) b) system timer to be replaced with PMU timer of R4 3. Having ResetHandler code with stackPointer initialization and memory allocation If any code with above few points included would be of great help for us ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [March 17, 2025, 2:58pm UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/4 "2025-03-17T14:58:15Z")
That is part of the application. Here is an example - [FreeRTOS/FreeRTOS/Demo/CORTEX\_No\_GIC\_R5F\_TI\_RM57\_HERCULES\_GCC/BoardFiles/source/sys\_intvecs.S at main · FreeRTOS/FreeRTOS · GitHub](https://github.com/FreeRTOS/FreeRTOS/blob/main/FreeRTOS/Demo/CORTEX_No_GIC_R5F_TI_RM57_HERCULES_GCC/BoardFiles/source/sys_intvecs.S). ---
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [April 1, 2025, 2:23pm UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/5 "2025-04-01T14:23:10Z")
Hi Gaurav, Thanks for the response. I have below follow up question:- 1. only Api “FreeRTOS\_SVC\_Handler” is sufficient for scheduling? or any other api’s to be added as part of scheduling like for ex:- in CM4 chip, api’s xPortPendSVHandler, vPortSVCHandler are added by one of our team member 2. Do we have any code for mapping timer tick or should we use default system time ticks? For CM4 one of our team member faced scheduler issue hence they have to use different timer interupt like interruptvector\_TIMER2\_DONE 3. For ARM\_CRx\_No\_GIC how do we know if our chip has EndOfInterupt register? ulICCEOIR = configEOI\_ADDRESS; ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 1, 2025, 4:44pm UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/6 "2025-04-01T16:44:39Z")
> [@sitikela](#): > > only Api “FreeRTOS\_SVC\_Handler” is sufficient for scheduling? or any other api’s to be added as part of scheduling like for ex:- in CM4 chip, api’s xPortPendSVHandler, vPortSVCHandler are added by one of our team member You need to install [FreeRTOS\_IRQ\_Handler](https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/main/portable/GCC/ARM_CRx_No_GIC/portASM.S#L337C1-L337C21) as the IRQ handler. > [@sitikela](#): > > Do we have any code for mapping timer tick or should we use default system time ticks? For CM4 one of our team member faced scheduler issue hence they have to use different timer interupt like interruptvector\_TIMER2\_DONE You need to [setup a timer](https://github.com/FreeRTOS/FreeRTOS/blob/main/FreeRTOS/Demo/CORTEX_MPU_R4F_TI_RM46_HERCULES_GCC/source/main.c#L232) and call [xTaskIncrementTick](https://github.com/FreeRTOS/FreeRTOS/blob/main/FreeRTOS/Demo/CORTEX_MPU_R4F_TI_RM46_HERCULES_GCC/source/main.c#L414) from the corresponding ISR. > [@sitikela](#): > > For ARM\_CRx\_No\_GIC how do we know if our chip has EndOfInterupt register? > ulICCEOIR = configEOI\_ADDRESS; You can refer to the documentation for your chip. ---
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [April 2, 2025, 7:22am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/7 "2025-04-02T07:22:00Z")
Hi Gaurav, WE are porting the FreeRtos for Cr4 without GIC, so should we use “ARM\_CRx\_No\_GIC” target? I am getting below error’s for Vpush, Vpop instruction and also for Floating point instruction like fmrx, vmsr in portASM.S and port.c file. Do we have any equivalent instructions or any workaround we can do for this ? i tried with some solutions like -mfpu=vfpv3-d16 option in makefile but those didn’t solve the issue. FreeRTOS-Kernel-11.1.0/portable/GCC/ARM\_CRx\_No\_GIC/portASM.S:137: Error: selected processor does not support `fmrxne R1,FPSCR' in ARM mode FreeRTOS-Kernel-11.1.0/portable/GCC/ARM_CRx_No_GIC/portASM.S:137: Error: selected processor does not support `vpushne {D0-D15}’ in ARM mode FreeRTOS-Kernel-11.1.0/portable/GCC/ARM\_CRx\_No\_GIC/portASM.S:140: Error: selected processor does not support `vpopne {D0-D15}' in ARM mode FreeRTOS-Kernel-11.1.0/portable/GCC/ARM_CRx_No_GIC/portASM.S:140: Error: selected processor does not support `vmsrne FPSCR,R0’ in ARM mode FreeRTOS-Kernel-11.1.0/portable/GCC/ARM\_CRx\_No\_GIC/portASM.S:151: Error: selected processor does not support `vpopne {D0-D15}’ Do we have any cr4 porting guide to see what all changes to be done and what code to be included and flags? ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 2, 2025, 8:31am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/8 "2025-04-02T08:31:02Z")
> [@sitikela](#): > > `Error: selected processor does not support `vpushne {D0-D15}’ in ARM mode Most likely you are not passing correct compiler flags. Did you pass `-mthumb`? ---
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [April 2, 2025, 8:38am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/9 "2025-04-02T08:38:25Z")
i could see that we are providing that option but even though in our code we mention our asm code as ".arm "instructions. So i tried even by removing that flag but still getting same error CFLAGS : -mcpu=cortex-r4 -mthumb -g -Wall -fno-common -fdata-sections -ffunction-sections -ffreestanding -fno-builtin -mapcs -fno-exceptions -MMD -MP -DEVAL\_43711 -std=c99 -O0 -DRTOS\_CONSOLE\_LOGS -DconfigSUPPORT\_STATIC\_ALLOCATION -D\_LANGUAGE\_ASSEMBLY -DFLOPS\_SUPPORT -DBCMDBG -DDEBUG\_MEMBUF" ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 2, 2025, 9:02am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/10 "2025-04-02T09:02:26Z")
You need to find the correct set of flags. You can try to refer to these - [FreeRTOS/FreeRTOS/Demo/CORTEX\_No\_GIC\_R5F\_TI\_RM57\_HERCULES\_GCC/CMakeLists.txt at main · FreeRTOS/FreeRTOS · GitHub](https://github.com/FreeRTOS/FreeRTOS/blob/main/FreeRTOS/Demo/CORTEX_No_GIC_R5F_TI_RM57_HERCULES_GCC/CMakeLists.txt#L19-L21). ---
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [April 2, 2025, 9:51am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/11 "2025-04-02T09:51:22Z")
Hi Gaurav, Adding below option has solved the above error. q1) But are we supposed to use only softfp or both softfp and hardfp instructions? how can we check it? -mfloat-abi=softfp -mfpu=vfpv3-d16 q3) Also i see undefined function vApplicationIRQHandler in ARM\_CRx\_No\_GIC/portASM.S:249. i don’t see definition of this function when grepped the code. Can we add this in our application main to handle required interupts? if yes can i get any reference code of this? q4) Do we have any reference on where to map this below label in interupt table? like the exact index to add this to svcEntry: b FreeRTOS\_SVC\_Handler ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 2, 2025, 2:35pm UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/12 "2025-04-02T14:35:13Z")
> [@sitikela](#): > > Adding below option has solved the above error. I do not think that is the correct solution. Does your hardware not have FPU? > [@sitikela](#): > > q3) Also i see undefined function vApplicationIRQHandler in ARM\_CRx\_No\_GIC/portASM.S:249. > Where do we get this function? i don’t see definition of this function when grepped the code Any function which has `Application` in its name, needs to come from the application. Here is an example of vApplicationIRQHandler - [FreeRTOS/FreeRTOS/Demo/CORTEX\_MPU\_R5F\_TI\_RM57\_HERCULES\_GCC/source/main.c at main · FreeRTOS/FreeRTOS · GitHub](https://github.com/FreeRTOS/FreeRTOS/blob/main/FreeRTOS/Demo/CORTEX_MPU_R5F_TI_RM57_HERCULES_GCC/source/main.c#L330). ---
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [April 2, 2025, 2:52pm UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/13 "2025-04-02T14:52:14Z")
q1)you mean for below option as softfp is not a correct solution? -mfloat-abi=softfp For hard option i see the error as below. Not sure if its issue related to libgcc.a i am using? /data/si/ARM\_Files/hndtools-armeabi-6.3.1/bin/../lib/gcc/arm-none-eabi/6.3.1/../../../../arm-none-eabi/bin/ld: error: build/mhd\_bt\_mcu\_43711.elf uses VFP register arguments, /data/si/ARM\_Files/hndtools-armeabi-6.3.1/bin/../lib/gcc/arm-none-eabi/6.3.1/thumb/v7-ar/libgcc.a(\_udivmoddi4.o) does not /data/si/ARM\_Files/hndtools-armeabi-6.3.1/bin/../lib/gcc/arm-none-eabi/6.3.1/../../../../arm-none-eabi/bin/ld: failed to merge target specific data of file /data/si/ARM\_Files/hndtools-armeabi-6.3.1/bin/../lib/gcc/arm-none-eabi/6.3.1/thumb/v7-ar/libgcc.a(\_udivmoddi4.o) /data/si/ARM\_Files/hndtools-armeabi-6.3.1/bin/../lib/gcc/arm-none-eabi/6.3.1/../../../../arm-none-eabi/bin/ld: error: build/mhd\_bt\_mcu\_43711.elf uses VFP register arguments, /data/si/ARM\_Files/hndtools-armeabi-6.3.1/arm-none-eabi/lib/thumb/libc.a(lib\_a-memcpy-stub.o) does not /data/si/ARM\_Files/hndtools-armeabi-6.3.1/bin/../lib/gcc/arm-none-eabi/6.3.1/../../../../arm-none-eabi/bin/ld: failed to merge target specific data of file /data/si/ARM\_Files/hndtools-armeabi-6.3.1/arm-none-eabi/lib/thumb/libc.a(lib\_a-memcpy-stub.o) /data/si/ARM\_Files/hndtools-armeabi-6.3.1/bin/../lib/gcc/arm-none-eabi/6.3.1/../../../../arm-none-eabi/bin/ld: error: build/mhd\_bt\_mcu\_43711.elf uses VFP register arguments, /data/si/ARM\_Files/hndtools-armeabi-6.3.1/arm-none-eabi/lib/thumb/libc.a(lib\_a-memset.o) does not /data/si/ARM\_Files/hndtools-armeabi-6.3.1/bin/../lib/gcc/arm-none-eabi/6.3.1/../../../../arm-none-eabi/bin/ld: failed to merge target specific data of file /data/si/ARM\_Files/hndtools-armeabi-6.3.1/arm-none-eabi/lib/thumb/libc.a(lib\_a-memset.o) q2) Do we have any reference on where to map this below label in interupt table? like the exact index to add this to svcEntry: b FreeRTOS\_SVC\_Handler ---
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [April 3, 2025, 5:23am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/14 "2025-04-03T05:23:32Z")
HI Gaurav, q1) Our Cr4 chip doesn’t support the fpu but supports mpu so using below options if fine then? -mfloat-abi=softfp -mfpu=vfpv3-d16 q2) Do we have any reference on where to map this below label in interupt table? like the exact index to add this to svcEntry: b FreeRTOS\_SVC\_Handler ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 3, 2025, 5:53am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/15 "2025-04-03T05:53:02Z")
> [@sitikela](#): > > q1) Our Cr4 chip doesn’t support the fpu but supports mpu so using below options if fine then? > -mfloat-abi=softfp -mfpu=vfpv3-d16 The port uses FPU registers. You probably need to guard the FPU parts in the port with `#if ( configENABLE_FPU == 1 )` and then set `configENABLE_FPU` to 0 in your `FreeRTOSConfig.h`. > [@sitikela](#): > > q2) Do we have any reference on where to map this below label in interupt table? like the exact index to add this to > svcEntry: > b FreeRTOS\_SVC\_Handler Please check the documentation for your chip. ---
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [April 10, 2025, 6:08am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/16 "2025-04-10T06:08:38Z")
Hi Gaurav, As suggested by you, i have disabled the FPU code by putting in the configENABLE\_FPU flag. Then removed the flags -mfloat-abi=softfp -mfpu=vfpv3-d16. Q1) Hope this is what you had suggested me right? Q2) I see one api “xPortPendSVHandler” in CM4 for task switching, is there any equivalent api in CR4 for this? Q3) Currently i can see that my application static task(xTaskCreateStatic) is getting added to ready list(prvAddNewTaskToReadyList) but while scheduling the task(vTaskStartScheduler), the code enters vPortRestoreTaskContext and here when accesing the taskControlBlock(pxCurrentTCBConst), the code jumps to “prvTaskExitError”, i have check that we are in Supervisor Mode (0x13). Is there anything we need to do for task to start the exectuion using TCB. ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 10, 2025, 6:34am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/17 "2025-04-10T06:34:41Z")
> [@sitikela](#): > > putting in the configENABLE\_FPU flag Where did you put this flag? Did you update the FreeRTOS port code? > [@sitikela](#): > > the code jumps to “prvTaskExitError”, Do you have a task which exits without calling vTaskDelete? ---
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [April 10, 2025, 11:53am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/18 "2025-04-10T11:53:42Z")
Q1) Where did you put this flag? Did you update the FreeRTOS port code? 1. i have defined FPU code under configUSE\_TASK\_FPU\_SUPPORT and set it to zero. 2) the FVP code was present in port.c and portAsm.s(for this asm file i have added the flag \_\_ARM\_FP) Q2) Do you have a task which exits without calling vTaskDelete As of now i have only one task creating in application, other two tasks are Timer and idle task which are handled by FreeRtos Code. So in application task i haven’t made any change which is same as FreeRtos code. is there any thing i need to add to application file? have attached the file for reference [main.c](https://forums.freertos.org/uploads/short-url/jPEAO7xWKyLPtqVGzmQMLgsyHcE.c) (5.5 KB) Q3) I see one api “xPortPendSVHandler” in CM4 for task switching, is there any equivalent api in CR4 for this? if this api not required then task switching happens automatically in CR4? ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 11, 2025, 5:54am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/19 "2025-04-11T05:54:01Z")
> [@sitikela](#): > > i have defined FPU code under configUSE\_TASK\_FPU\_SUPPORT and set it to zero. > 2) the FVP code was present in port.c and portAsm.s(for this asm file i have added the flag \_\_ARM\_FP) That is the right thing do. Once we get it working, feel free to open a PR to contribute this change. > [@sitikela](#): > > As of now i have only one task creating in application Your task definition looks correct. > [@sitikela](#): > > I see one api “xPortPendSVHandler” in CM4 for task switching You do not need it in Cortex-R. Are you able to step though the assembly of vPortRestoreTaskContext? If yes, which instruction takes you to prvTaskExitError? ---
**Author:** ![sitikela](https://avatars.discourse-cdn.com/v4/letter/s/c57346/32.png) [@sitikela](https://forums.freertos.org/u/sitikela)\ **Post date:** [April 14, 2025, 7:09am UTC](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731/20 "2025-04-14T07:09:35Z")
Hi Gaurav, Thanks for the response. If code works yes i can do raise a PR. But we need to make the code to get to working stage. For your query related to switching to prvTaskExitError, below is my code and the pc points to addr “202db4” below and then when i give step instruction in gdb, pc jumps to prvTaskExitError. This is what i am observing now. Let me know your thoughts on this. 00202db0 : 202db0: f102001f cps #31 202db4: e59f0124 ldr r0, [pc, #292] ; 202ee0 202db8: e5901000 ldr r1, [r0] 202dbc: e591d000 ldr sp, [r1] 00202a44 : 202a44: b480 push {r7} 202a46: af00 add r7, sp, #0 202a48: f24c 0350 movw r3, #49232 ; 0xc050 q3) if xPortPendSVHandler is not needed in CR4, how does context switching between task happends? [Next page](https://forums.freertos.org/t/requesting-freertos-port-code-to-cr-4-series/22731.md?page=2)