Blitter

A blitter is a circuit, sometimes as a coprocessor or a logic block on a microprocessor, dedicated to the rapid movement and modification of data within a computer's memory.

A typical use for a blitter is the movement of a bitmap, such as windows and icons in a graphical user interface or images and backgrounds in a 2D video game.

For fundamental graphics routines, like compositing a smaller image into a larger one (such as for a video game) or drawing a filled rectangle, large amounts of memory need to be manipulated, and many cycles are spent fetching and decoding short loops of load/store instructions.

The first US patent filing to use the term blitter was "Personal computer apparatus for block transfer of bit-mapped image data," assigned to Commodore-Amiga, Inc.[10] The blitter performs an arbitrary boolean operation on three bit vectors of size 16: 1986: The TMS34010 is a general purpose 32-bit processor with built-in instructions, including PIXBLT (Pixel Block Transfer), for manipulating bitmap data.

It is optimized for cases that would take extra processing if implemented in software, such as handling transparent pixels, working with non-byte aligned data, and converting between bit depths.

[11] The TMS34010 serves as both CPU and GPU for a number of arcade games starting in 1988 with Narc and including Hard Drivin', Smash TV, Mortal Kombat, and NBA Jam, [12] It was also used in graphics accelerator boards in the 1990s.

[14] Officially called the "Atari ST Bit-Block Transfer Processor", stylized as BLiTTER, it provides 16 options for merging source and destination data.

[17] 1996: The VESA Group introduced a standardized way to access features like hardware Bit Block transfers with VBE/accelerator functions (VBE/AF) on IBM PC compatibles.

Typically, a computer program puts information into certain hardware registers describing what memory transfer needs to be completed and the logical operations to perform on the data.

The logical operation is: Hardware sprites are small bitmaps which can be positioned independently and are composited together with the background on-the-fly by the video chip.