Counting modified bits in a 32bit data word

So bit0 and bit1 have changed.
Now I would have counter[1]++ and counter[0]++;

Sorry for that, ok, I try again…

I have to count bit changes in a 32bit data word, separated for each bit.
Therefore I have 32 distinct counters in an array named counter32[32].

counter32[0] counts bit changes of bit0, counter32[1] counts bit changes of bit1, and so on.

Every time a bit changes, its counter should be incremented.
olddata := 0x00000002; newdata := 0x00000001;
olddata ^ newdata gives 0x00000011, so two bits changed.
Here two bits have changed, bit0 and bit1, so counter32[0]++ and counter32[1]++

Best regards
Juergen

So bit0 and bit1 have changed.
Now I would have counter[1]++ and counter[0]++;

Sorry for that, ok, I try again…

I have to count bit changes in a 32bit data word, separated for each bit.
Therefore I have 32 distinct counters in an array named counter32[32].

counter32[0] counts bit changes of bit0, counter32[1] counts bit changes of bit1, and so on.

Every time a bit changes, its counter should be incremented.
olddata := 0x00000002; newdata := 0x00000001;
olddata ^ newdata gives 0x00000011, so two bits changed.
Here two bits have changed, bit0 and bit1, so counter32[0]++ and counter32[1]++

Best regards
Juergen

I think something like this.
But this is tooo slow for our needs and I have no knowledge of ARM Assembler...
MCU is a STM32G0 with Cortex-M0+.

uint32_t counter32[32];
olddata = 0x00000001U;
newdata = 0x00000002U;

void CountBits(uint32_t old, uint32_t new)
{
    uint32_t x;
    uint32_t mask = 0x00000001U;
    int      i;

    x = old ^ new;			// x == 0x00000003
    for (i = 0; i < 32; i++)
    {
        if (x & mask)
            counter[i]++;
        mask <<= 1;
    }        
}


void main (void)
{
    CountBits (olddata, newdata);
}