Compare

The Need for a Detailed Compare The standard `memcmp′ routine (Part 89) tells you only if two blocks are the same or different. For debugging purposes, you often need to know where the corruption or difference first occurred. Goal: Compare two memory blocks, and if they differ, return the address of the first byte that does not match. The Comparison Strategy We will modify the simple comparison loop to preserve the address and exit immediately upon the first failure. ...

The Need for Block Search and Compare In system programming, you need routines to: Search (memchr): Find the first occurrence of a specific character (e.g., a null terminator, space, or command byte) within a buffer. Compare (memcmp): Verify that two large blocks of memory (e.g., two versions of a game level, or a password against a stored hash) are identical. Routine 1: Block Search (memchr) Block Search scans a memory area for the first occurrence of a specific 8-bit value. ...