Converting Bytes to signed short and int value to bytes

Question

I have int values of two bytes for example 254 = 0xFE, 112 = 0x70 . I need to convert them to signed short. Now the signed short value should be -400.

And then after changing that value I have an integer for example -410 that i need to convert back to two bytes.

How could i achieve that for iOS?

Answer 1

If the bytes are in the native architecture endianness , then it's as simple as

uint8_t *p = someAddress;
short value = *(short *)p;

value = 410;
*(short *)p = value;

However if the bytes are in a foreign endianness you are required to convert each byte of the integer, which is slow. Here is one, of many, examples.