How to translate below code from C to COS?

void encode_value (unsigned char value, unsigned char *tx)

{

tx [1] = ((value & 0xf0) >> 4) + 0x20;

tx [0] = (value & 0x0f) + 0x20;

}

unsigned char decode_value (unsigned char *rx)

{ unsigned char temp_value = 0; temp_value = (rx [1] - 0x20) << 4;

return (temp_value + rx [0] - 0x20);

}