Understanding output of code

1 
#if SS_VER == SS_VER_2_1
uint8_t glitch_loop(uint8_t cmd, uint8_t scmd, uint8_t len, uint8_t* in)
#else
uint8_t glitch_loop(uint8_t* in, uint8_t len)
#endif
{
    volatile uint16_t i, j;
    volatile uint32_t cnt;
    cnt = 0;
    trigger_high();
    for(i=0; i<50; i++){
        for(j=0; j<50; j++){
            cnt++;
        }
    }
    trigger_low();
    simpleserial_put('r', 4, (uint8_t*)&cnt);
#if SS_VER == SS_VER_2_1
    return (cnt != 2500) ? 0x10 : 0x00;
#else
    return (cnt != 2500);
#endif
}

i am getting result from the code

rC4090000
z00

but but the cnt value should be 2500 then why am i getting this value can you explain.

2

09C4 is 2500 in hexadecimal

3

Why it is in reverse order :sweat_smile:

4

Because Arm processors are little endian.

5

Hello Alex,

In this case, when I have to give an input to chipwhisperer via python script,
for example, inp = “\x00\x01x\x0a\xFF” , do I need to switch the input as “\xFFx\0a\x01\x00” since the controller is storing in little-endian format?

6

You only need to worry about byte order if you’re converting from multiple single bytes to multi byte numbers. In the above example, the number is being converted from a 4 byte array into a 32-bit integer.

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