Search results
Results from the WOW.Com Content Network
In 8-bit CP/M versions it is located in the first 256 bytes of memory, hence its name. The equivalent structure in DOS is the Program Segment Prefix (PSP), a 256-byte (page-sized) structure, which is by default located exactly before offset 0 of the program's load segment, rather than in segment 0.
In computer architecture, 256-bit integers, memory addresses, or other data units are those that are 256 bits (32 octets) wide. Also, 256-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers , address buses , or data buses of that size.
The size of a page depends on the context, and the significance of zero page memory versus higher addressed memory is highly dependent on machine architecture. For example, the Motorola 6800 and MOS Technology 6502 processor families treat the first 256 bytes of memory specially, [1] whereas many other processors do not.
On most modern computers, this is an eight bit string. Because the definition of a byte is related to the number of bits composing a character, some older computers have used a different bit length for their byte. [2] In many computer architectures, the byte is the smallest addressable unit, the atom of addressability, say. For example, even ...
MCS-51-based microcontrollers typically include one or two UARTs, two or three timers, 128 or 256 bytes of internal data RAM (16 bytes of which are bit-addressable), up to 128 bytes of I/O, 512 bytes to 64 KB of internal program memory, and sometimes a quantity of extended data RAM (ERAM) located in the external data space. External RAM and ROM ...
1,024 bits (128 bytes) - RAM capacity of the Atari 2600: 1,288 bits (161 bytes) – approximate maximum capacity of a standard magnetic stripe card: 2 11: 2,048 bits (256 bytes) – RAM capacity of the stock Altair 8800: 2 12: 4,096 bits (512 bytes) – typical sector size, and minimum space allocation unit on computer storage volumes, with ...
(Because the AVR program counter counts 16-bit words, not bytes, a 12-bit offset is sufficient to address 2 13 bytes of ROM.) Additional memory addressing capabilities are present as required to access available resources: Models with >256 bytes of data address space (≥256 bytes of RAM) have a 16-bit stack pointer, with the high half in the ...
Designers of these processors included a partial remedy known as "zero page" addressing. The initial 256 bytes of memory ($0000 – $00FF; a.k.a., page "0") could be accessed using a one-byte absolute or indexed memory address. This reduced instruction execution time by one clock cycle and instruction length by one byte.