Hi, I am trying to get the FPU going on XMC4200 but for some reason I am not able to get the expected performance. I am using the latest version of DA...
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Hi, I am trying to get the FPU going on XMC4200 but for some reason I am not able to get the expected performance. I am using the latest version of DAVE.
In the attached project:
1. I enabled the FPU: SCB->CPACR |= 0x00F00000; //Enable FPU
2. I have two functions, a square root and a multiplication and some pin toggles for time measurements on the oscilloscope.
3. I measure approximately 390 clock cycles for the square root and 26 clock cycles for the multiplication. I think these times are too long and they don't change much even if the FPU is not enabled. So, I think I am not using the FPU correctly.
I would very much appreciate it if anyone can help me to find the problem. I tried all the suggestions in this forum by changing the active project properties but observed no improvement.
I also copied the "main.c" file below, which is the only file that I created in the project.
I look forward to hearing from you. Thanks in advance.
Yalcin
========main.c========
#include "DAVE.h"
#include <math.h>
float A = 555;
float B;
float C;
int main(void)
{
SCB->CPACR |= 0x00F00000; //Enable FPU
PORT1->IOCR0 |= 0x800000; //Bit23 set to 1 for push-pull output P1.2, Board pin 13
while(1U)
{
PORT1->OMR |= (1u << 2); //Setting OMR bit 2 for P1.2 high.
PORT1->OMR |= 0x40000; //Setting OMR bit 18 high for P1.2 low.
PORT1->OMR |= (1u << 2); //Setting OMR bit 2 for P1.2 high.
B = sqrtf(A); //4840 ns (~390 clock cycles)
PORT1->OMR |= 0x40000; //Setting OMR bit 18 high for P1.2 low.
PORT1->OMR |= (1u << 2); //Setting OMR bit 2 for P1.2 high.
C = A * B; //327 ns (~26 clock cycles)
PORT1->OMR |= 0x40000; //Setting OMR bit 18 high for P1.2 low.
}
}
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