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Mostek 5065
The Mostek MK5065 was an 8-bit microprocessor introduced by Mostek in early 1974. The design was originally developed by Motorola for use in an Olivetti electronic calculator, and was licensed to Mostek for use in non-calculator roles. It featured three sets of processor registers, allowing it to switch to an interrupt handler in a single cycle, and a wait-for-data mode that aided direct memory access. In spite of a relatively low cost (for the era) of $58 in quantities of 100, the 5065 appears to have seen little use. The Fairchild F8 was introduced at about the same time, aimed at the same markets. The F8 had a number of advantages over the 5065 due to its more modern design. In June 1975, Mostek licensed the F8 under a second source arrangement. The 5065 disappeared from Mostek's 1975 catalog, which mentions only their F8, the MK3850. History The 5065 began as a custom PMOS CPU design by Motorola for a desktop calculator being built by Olivetti. The design effort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mostek
Mostek was a semiconductor integrated circuit manufacturer, founded in 1969 by L. J. Sevin, Louay E. Sharif, Richard L. Petritz and other ex-employees of Texas Instruments. At its peak in the late 1970s, Mostek held an 85% market share of the dynamic random-access memory (DRAM) memory chip market worldwide, until being eclipsed by lower-priced Japanese DRAM manufacturers who were accused of dumping memory on the market. Initially Mostek products were manufactured in Worcester, Massachusetts in cooperation with Sprague Electric, however by 1974 most of its manufacturing was done in the Carrollton, Texas facility on Crosby Road. In 1979, soon after its market peak, Mostek was purchased by United Technologies Corporation for . In 1985, after several years of red ink and declining market share, UTC closed Mostek completely and sold it for to the French electronics firm Thomson-CSF, which later spun it off into STMicroelectronics. Early Products Mostek's first contract was from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microcontroller
A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals. Program memory in the form of ferroelectric RAM, NOR flash or OTP ROM is also often included on chip, as well as a small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications consisting of various discrete chips. In modern terminology, a microcontroller is similar to, but less sophisticated than, a system on a chip (SoC). An SoC may connect the external microcontroller chips as the motherboard components, but an SoC usually integrates the advanced peripherals like graphics processing unit (GPU) and Wi-Fi interface controller as its internal microcontroller unit circuits. Microcontrollers are use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Memory Page
A page, memory page, or virtual page is a fixed-length contiguous block of virtual memory, described by a single entry in the page table. It is the smallest unit of data for memory management in a virtual memory operating system. Similarly, a page frame is the smallest fixed-length contiguous block of physical memory into which memory pages are mapped by the operating system. A transfer of pages between main memory and an auxiliary store, such as a hard disk drive, is referred to as paging or swapping. Page size trade-off Page size is usually determined by the processor architecture. Traditionally, pages in a system had uniform size, such as 4,096 bytes. However, processor designs often allow two or more, sometimes simultaneous, page sizes due to its benefits. There are several points that can factor into choosing the best page size. Page table size A system with a smaller page size uses more pages, requiring a page table that occupies more space. For example, if a 232 vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bit Shift
In computer programming, a bitwise operation operates on a bit string, a bit array or a binary numeral (considered as a bit string) at the level of its individual bits. It is a fast and simple action, basic to the higher-level arithmetic operations and directly supported by the processor. Most bitwise operations are presented as two-operand instructions where the result replaces one of the input operands. On simple low-cost processors, typically, bitwise operations are substantially faster than division, several times faster than multiplication, and sometimes significantly faster than addition. While modern processors usually perform addition and multiplication just as fast as bitwise operations due to their longer instruction pipelines and other architectural design choices, bitwise operations do commonly use less power because of the reduced use of resources. Bitwise operators In the explanations below, any indication of a bit's position is counted from the right (least signi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Return Statement
In computer programming, a return statement causes execution to leave the current subroutine and resume at the point in the code immediately after the instruction which called the subroutine, known as its return address. The return address is saved by the calling routine, today usually on the process's call stack or in a register. Return statements in many programming languages allow a function to specify a return value to be passed back to the code that called the function. Overview In C and C++, return ''exp''; (where ''exp'' is an expression) is a statement that tells a function to return execution of the program to the calling function, and report the value of ''exp''. If a function has the return type void, the return statement can be used without a value, in which case the program just breaks out of the current function and returns to the calling one. In Pascal there is no return statement. (However, in newer Pascals, the Exit(''exp''); can be used to return a value imm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operand
In mathematics, an operand is the object of a mathematical operation, i.e., it is the object or quantity that is operated on. Example The following arithmetic expression shows an example of operators and operands: :3 + 6 = 9 In the above example, '+' is the symbol for the operation called addition. The operand '3' is one of the inputs (quantities) followed by the addition operator, and the operand '6' is the other input necessary for the operation. The result of the operation is 9. (The number '9' is also called the sum of the augend 3 and the addend 6.) An operand, then, is also referred to as "one of the inputs (quantities) for an operation". Notation Expressions as operands Operands may be complex, and may consist of expressions also made up of operators with operands. :(3 + 5) \times 2 In the above expression '(3 + 5)' is the first operand for the multiplication operator and '2' the second. The operand '(3 + 5)' is an expression in itself, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opcode
In computing, an opcode (abbreviated from operation code, also known as instruction machine code, instruction code, instruction syllable, instruction parcel or opstring) is the portion of a machine language instruction that specifies the operation to be performed. Beside the opcode itself, most instructions also specify the data they will process, in the form of operands. In addition to opcodes used in the instruction set architectures of various CPUs, which are hardware devices, they can also be used in abstract computing machines as part of their byte code specifications. Overview Specifications and format of the opcodes are laid out in the instruction set architecture ( ISA) of the processor in question, which may be a general CPU or a more specialized processing unit. Opcodes for a given instruction set can be described through the use of an opcode table detailing all possible opcodes. Apart from the opcode itself, an instruction normally also has one or more specifiers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stack Pointer
In computer science, a call stack is a stack data structure that stores information about the active subroutines of a computer program. This kind of stack is also known as an execution stack, program stack, control stack, run-time stack, or machine stack, and is often shortened to just "the stack". Although maintenance of the call stack is important for the proper functioning of most software, the details are normally hidden and automatic in high-level programming languages. Many computer instruction sets provide special instructions for manipulating stacks. A call stack is used for several related purposes, but the main reason for having one is to keep track of the point to which each active subroutine should return control when it finishes executing. An active subroutine is one that has been called, but is yet to complete execution, after which control should be handed back to the point of call. Such activations of subroutines may be nested to any level (recursive as a special ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Call Stack
In computer science, a call stack is a stack data structure that stores information about the active subroutines of a computer program. This kind of stack is also known as an execution stack, program stack, control stack, run-time stack, or machine stack, and is often shortened to just "the stack". Although maintenance of the call stack is important for the proper functioning of most software, the details are normally hidden and automatic in high-level programming languages. Many computer instruction sets provide special instructions for manipulating stacks. A call stack is used for several related purposes, but the main reason for having one is to keep track of the point to which each active subroutine should return control when it finishes executing. An active subroutine is one that has been called, but is yet to complete execution, after which control should be handed back to the point of call. Such activations of subroutines may be nested to any level (recursive as a speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zero Page
The zero page or base page is the block of memory at the very beginning of a computer's address space; that is, the page whose starting address is zero. 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, whereas many other processors do not. Unlike more modern hardware, in the 1970s computer RAM was as fast as or faster than the CPU. Thus it made sense to have few registers and use the main memory as an extended pool of extra registers. In machines with a relatively wide 16-bit address bus and comparatively narrow 8-bit data bus, accessing zero page locations could be faster than accessing other locations. Zero page addressing now has mostly historical significance, since the developments in integrated circuit technology have made adding more registers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carry Flag
In computer processors the carry flag (usually indicated as the C flag) is a single bit in a system status register/flag register used to indicate when an arithmetic carry or borrow has been generated out of the most significant arithmetic logic unit (ALU) bit position. The carry flag enables numbers larger than a single ALU width to be added/subtracted by carrying (adding) a binary digit from a partial addition/subtraction to the least significant bit position of a more significant word. This is typically programmed by the user of the processor on the assembly or machine code level, but can also happen internally in certain processors, via digital logic or microcode, where some processors have wider registers and arithmetic instructions than (combinatorial, or "physical") ALU. It is also used to extend bit shifts and rotates in a similar manner on many processors (sometimes done via a dedicated flag). For subtractive operations, two (opposite) conventions are employed as most ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Program Counter
The program counter (PC), commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer, is a processor register that indicates where a computer is in its program sequence. Usually, the PC is incremented after fetching an instruction, and holds the memory address of (" points to") the next instruction that would be executed. Processors usually fetch instructions sequentially from memory, but ''control transfer'' instructions change the sequence by placing a new value in the PC. These include branches (sometimes called jumps), subroutine calls, and returns. A transfer that is conditional on the truth of some assertion lets the computer follow a different sequence under different conditions. A branch provides that the next instruction is fetched from elsewhere in memory. A subroutine call not only branches but saves the preced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
