I experienced the following failed assertion when debugging Cortex-M4F code using floating point.
GCC-4-8-build/src/gdb/gdb/regcache.c:178: internal-error:
register_size: Assertion `regnum >= 0 && regnum <
(gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch))' failed.
All routine that pass a floating point value to the routine will failed when I set a breakpoint inside the routine. GDB crashes as soon as the break is encountered.
Kinetis Design Studio Version: 3.1.0
Eclipse Version: Luna SR2 (4.4.2)
Hi,
I listed my compiler setting on
arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -mthumb-interwork -mfloat-abi=hard
-mfpu=fpv4-sp-d16 -Og -fmessage-length=0 -fsigned-char -ffunction-sections
-fdata-sections -fsingle-precision-constant -Wunused -Wuninitialized
-Wmissing-declarations -Wlogical-op -Waggregate-return -g3 -nostdinc
-D_AEABI_LC_CTYPE=C -D__STRICT_ANSI__=1 -D_DEBUG=1
-std=gnu11 -Wmissing-prototypes -Wstrict-prototypes
-fno-strict-aliasing -fms-extensions -finline-functions
My program compile, linked and run fine. I have a large amount of floating point math in this program and It's all is working fine. My problem is with the debugger first I have no floating point register display.
The old compiler Version 10.6 I had floating point register
listed after the control register. I the compiler version 3.2 there are no
floating point register listed. I the Expressions windows all float are listed
as hex number very hard to interpreter.
The second problem is when I set a break point in a subroutine that passes a float on the stack the debugger will crash when the break is encounter. I think the debugger is trying to read for float that was passed on the stack and get an error.
console window:
"GCC-4-8-build/src/gdb/gdb/regcache.c:178: internal-error:
register_size: Assertion `regnum >= 0 && regnum < (gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch))' failed."
These problem just make debugging harder. THis is the display from version 10.6 with floating point register.
Jim Burton
AMS Controls Inc.
314-344-3144 ext 108
Hi Dan,
I'll try using KSDK_v2 with KDS_3.2 (and FRDM-KV31 if I can find one) later but I did a quick check using KSDK_v1.3+KDS3.1 using FRDM-K64F and I can see the floating point registers in the Register window as follows:
I added simple floating code example:
#if 1 //DES 1=test, 0=default code
unsigned int i;
float x,y,z;
x = 3.14;
y = 2.2;
for(i=0;i<10;i++) {
z = x*y;
y += i;
x += (2*i);
}
#endif
I could monitor the local variable in the Variables window and also see the Register s14 and s15 being used for floating point.
Regards,
David
Hi Dan,
I just tested this same setup on the FRDM-KV31F successfully.
I used the HelloWorld demo project and to have the PRINTF working for %f float stuff I had to make following change in the properties:
Then recompiled and ran.
Terminal output:
hello world.
x = 93.139999y = 47.200001z = 2870.348145
Regards,
David
Hi David,
I followed your advice but I still can't get the FPU registers to show up in the Registers view as you have in your screen shot. Here is what my IDE looks like - peripheral registers on the left and core registers on the right.
Do you remember if you had to make any IDE changes to enable FPU registers to be included in the Registers view?
The alternative of using printf or similar console printing functionality from assembly language is not as convenient when stepping through code.
Thank you for your support,
Dan
Hi Dan,
have you tried the 'default' format?
Related to that, see Debugging Variables in Hexadecimal with Eclipse | MCU on Eclipse and Show Floating Point Variable Bytes in Eclipse CDT | MCU on Eclipse .
I hope this helps,
Erich
David,
Have you heard anything from PEMicro. I'm trying to write some FP assembly and I could really use this functionality. I saw there was a J-Link personality available for OpenSDA. Is this another path to getting a FP register view?
Shawn
Hi Jim,
I created a simple test case, and at least this one is working fine for me (see attached screenshot, using KDS v3.2.0) on a K22FN512.
My application (well, with FreeRTOS) does enable the floating point (FPU) unit. I assume the same is done on your side too?
void vPortEnableVFP(void) {
/* The FPU enable bits are in the CPACR. */
__asm volatile (
" ldr.w r0, =0xE000ED88 \n" /* CAPCR, 0xE000ED88 */
" ldr r1, [r0] \n" /* read CAPR */
" orr r1, r1, #(0xf<<20) \n" /* enable CP10 and CP11 coprocessors */
" str r1, [r0] \n" /* store to new value back */
: /* no output */
: /* no input */
: "r0","r1" /* clobber */
);
}
You might call the above code from main() to be sure your FPU is enabled.
Otherwise, it could be that your application might not be compiled with the correct floating point options? At least gdb complains about the register numbers.
This is what I have:
So these options should result somthing like this (pay attention to the -mcpu and -mfloat and -mfpu options) for compiler and linker:
Building file: ../source/main.c
Invoking: Cross ARM C Compiler
arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -mfpu=fpv4-sp-d16 -O0 -fmessage-length=0 -fsigned-char -ffunction-sections -fdata-sections -Wall -g3 -D_DEBUG=1 -DCPU_MK22FN512VLH12 -DUSB_STACK_FREERTOS_HEAP_SIZE=32768 -DUSB_STACK_FREERTOS -DFSL_RTOS_FREE_RTOS -DFRDM_K22F -DFREEDOM -I../freertos/Source/include -I../startup -I../board -I../utilities -I../freertos/Source/portable/GCC/ARM_CM4F -I../CMSIS -I../source ... -I../source/UTILITY -std=gnu99 -MMD -MP -MF"source/main.d" -MT"source/main.o" -c -o "source/main.o" "../source/main.c"
Finished building: ../source/main.c
Building target: FRDM-K22F_USB_Mouse_Kybd_SDK_v2.0.elf
Invoking: Cross ARM C++ Linker
arm-none-eabi-g++ -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -mfpu=fpv4-sp-d16 -O0 -fmessage-length=0 -fsigned-char -ffunction-sections -fdata-sections -Wall -g3 -T "../MK22FN512xxx12_flash.ld" -Xlinker --gc-sections -Wl,-Map,"FRDM-K22F_USB_Mouse_Kybd_SDK_v2.0.map" -specs=nosys.specs -specs=nano.specs -Xlinker -z -Xlinker muldefs -o "FRDM-K22F_USB_Mouse_Kybd_SDK_v2.0.elf" ./utilities/fsl_debug_console.o ... ./board/pin_mux.o
Finished building target: FRDM-K22F_USB_Mouse_Kybd_SDK_v2.0.elf
I hope this helps,
Erich
