Hi, am working on a security protocol SH256 however i can't understand this line even though there is a comment
// DBL_INT_ADD treats two unsigned ints a and b as one 64-bit integer and adds c to it
#define DBL_INT_ADD(a,b,c) if (a > 0xffffffff - (c)) ++b; a += c;
he compared "a" with (0xffffffff - (c)) then as the comment says he concatenated "a" and "b" then adds "c" to "a" ? is that it ?
but if a ,b and c are all integer (4 bytes) than "a "will never be greater than (0xffffffff - (c)) !!?
// DBL_INT_ADD treats two unsigned ints a and b as one 64-bit integer and adds c to it
#define DBL_INT_ADD(a,b,c) if (a > 0xffffffff - (c)) ++b; a += c;
he compared "a" with (0xffffffff - (c)) then as the comment says he concatenated "a" and "b" then adds "c" to "a" ? is that it ?
but if a ,b and c are all integer (4 bytes) than "a "will never be greater than (0xffffffff - (c)) !!?