tavuyhteenlaskun

Tavuyhteenlaskun, or byte addition, is the arithmetic operation of adding two or more bytes in digital systems. A byte typically consists of eight bits, and addition is usually performed modulo 256, producing an 8-bit result with an optional carry-out signifying overflow beyond the byte boundary.

In multi-byte values, addition proceeds byte by byte, starting from the least significant byte. A carry may be produced by each addition and is carried into the next higher byte. Implementations may use a ripple carry adder or more advanced carry-propagation techniques to reduce latency.

Overflow and flags: For unsigned values, a nonzero carry-out indicates an overflow. For signed values represented in two's complement, overflow occurs when the sign bits of the operands are equal but the sign of the result differs. CPUs expose related status flags such as carry (CF) and overflow (OF).

Endianness and memory layout: The mathematical result of tavuyhteenlasku is independent of byte order, but in memory it is arranged according to the system's endianness; algorithms for multi-byte addition must access bytes in the proper order to propagate carries correctly.

Applications: It is a fundamental operation in processors, compilers, and software libraries for multi-byte and big-integer arithmetic. It also appears in networking through variant forms like one's complement addition used in 16-bit checksums.

Example: adding 0x7F and 0x90 yields 0x0F with a carry-out of 1. This illustrates wrap-around behavior in an 8-bit byte and how a carry flag signals an overflow beyond the byte boundary.