Memset

The Need for a Fast Block Clear Initializing memory to zero is one of the most common tasks in low-level programming (the equivalent of calling memset(ptr, 0, size) in C). Since the Z80 needs to clear large buffers, a highly optimized routine is essential. Goal: Fill a specified memory range (START_ADDR′ to END_ADDR′) with the byte value `00H′ as quickly as possible. The Optimized Strategy: Using LDIR The fastest method is a slight modification of the Block Fill routine (Part 85), exploiting the `LDIR′ (Load, Increment, Repeat) instruction. ...

The Need for a Fast Block Fill In game development and system programming, you frequently need to clear large areas of RAM—such as setting the entire screen buffer to a black background or zeroing out a data structure. Doing this one byte at a time with a simple loop is slow. Goal: Write a routine that fills a specified memory range (START_ADDR′ to END_ADDR′) with a single constant byte (`FILL_BYTE′) as quickly as possible. ...