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MOS Technology 65CE02
The CSG 65CE02 is an 8/16-bit microprocessor developed by Commodore Semiconductor Group in 1988. It is a member of the MOS Technology 6502 family, developed from the CMOS WDC 65C02 released by the Western Design Center in 1983. Like the 65C02, the 65CE02 was built on a 2 µm CMOS process instead of the original 6502's 8 µm NMOS technology, making the chip smaller (and thus less expensive) as well as using much less power. In addition to changes made in the 65C02, the 65CE02 also included improvements to the processor pipeline to allow one-byte instructions to complete in 1 cycle, rather than the 6502's (and most variants) minimum of 2 cycles. It also removed 1 cycle delays when crossing page boundaries. These changes improved performance as much as 25% at the same clock speed. Other changes included the addition of a third index register, Z, along with the addition and modification of a number of instructions to use this register. The zero-page, the first 256 byt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore Semiconductor Group
MOS Technology, Inc. ("MOS" being short for Metal Oxide Semiconductor), later known as CSG (Commodore Semiconductor Group) and GMT Microelectronics, was a integrated circuit, semiconductor design and Semiconductor device fabrication, fabrication company based in Audubon, Pennsylvania. It is most famous for its MOS Technology 6502, 6502 microprocessor and various designs for Commodore International's range of home computers. History Three former General Instrument executives, John Paivinen, Mort Jaffe and Don McLaughlin, formed MOS Technology in Valley Forge, Pennsylvania in 1969. The Allen-Bradley, Allen-Bradley Company was looking to provide a second source for electronic calculators and their chips designed by Texas Instruments (TI). In 1970 Allen-Bradley acquired a majority interest in MOS Technology. In the early 1970s, TI decided to release their own line of calculators, instead of selling just the chips inside them, and introduced them at a price that was lower than ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overflow Flag
In computer processors, the overflow flag (sometimes called the V flag) is usually a single bit in a system status register used to indicate when an arithmetic overflow has occurred in an operation, indicating that the signed Two's complement, two's-complement result would not fit in the number of bits used for the result. Some architectures may be configured to automatically generate an exception on an operation resulting in overflow. An example, suppose we add 127 and 127 using 8-bit registers. 127+127 is 254, but using 8-bit arithmetic the result would be 1111 1110 binary, which is the two's complement encoding of −2, a negative number. A negative sum of positive operands (or vice versa) is an overflow. The overflow flag would then be set so the program can be aware of the problem and mitigate this or signal an error. The overflow flag is thus set when the most significant bit (here considered the sign bit) is changed by adding two numbers with the same sign (or subtracting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Addressing Mode
Addressing modes are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressing modes that are defined in a given instruction set architecture define how the machine language instructions in that architecture identify the operand(s) of each instruction. An addressing mode specifies how to calculate the effective memory address of an operand by using information held in registers and/or constants contained within a machine instruction or elsewhere. In computer programming, addressing modes are primarily of interest to those who write in assembly languages and to compiler writers. For a related concept see orthogonal instruction set which deals with the ability of any instruction to use any addressing mode. Caveats Note that there is no generally accepted way of naming the various addressing modes. In particular, different authors and computer manufacturers may give different names to the same addressing mode, or the same na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accumulator (computing)
In a computer's central processing unit (CPU), the accumulator is a register in which intermediate arithmetic logic unit results are stored. Without a register like an accumulator, it would be necessary to write the result of each calculation (addition, multiplication, shift, etc.) to main memory, perhaps only to be read right back again for use in the next operation. Access to main memory is slower than access to a register like an accumulator because the technology used for the large main memory is slower (but cheaper) than that used for a register. Early electronic computer systems were often split into two groups, those with accumulators and those without. Modern computer systems often have multiple general-purpose registers that can operate as accumulators, and the term is no longer as common as it once was. However, to simplify their design, a number of special-purpose processors still use a single accumulator. Basic concept Mathematical operations often take place i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Code Density
In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ''implementation''. In general, an ISA defines the supported instructions, data types, registers, the hardware support for managing main memory, fundamental features (such as the memory consistency, addressing modes, virtual memory), and the input/output model of a family of implementations of the ISA. An ISA specifies the behavior of machine code running on implementations of that ISA in a fashion that does not depend on the characteristics of that implementation, providing binary compatibility between implementations. This enables multiple implementations of an ISA that differ in characteristics such as performance, physical size, and monetary cost (among other things), but that are capable of running the same machine code, so that a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signetics
Signetics Corporation was an American electronics manufacturer specifically established to make integrated circuits. Founded in 1961, they went on to develop a number of early microprocessors and support chips, as well as the widely used 555 timer chip. The company was bought by Philips in 1975 and incorporated in Philips Semiconductors (now NXP). History Signetics was started in 1961, by a group of engineers (David Allison, David James, Lionel Kattner, and Mark Weissenstern) who had left Fairchild Semiconductor. At the time, Fairchild was concentrating on its discrete component business (mostly transistors), and its management felt that by making integrated circuits (ICs) it would lose its customers. Signetics founders believed that ICs were the future of electronics (much like another contemporary Fairchild spinoff, Amelco) and wished to commercialize them. The name of the new company was coined from Signal Network Electronics. The venture was financed by a group organized t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rockwell Semiconductor
Rockwell may refer to: Arts, entertainment, and media * ''Rockwell'' (album), a 2009 mini-album by Anni Rossi * Rockwell, a fictional town and setting of ''They Hunger'' * ''Rockwell'', a 1994 film about Porter Rockwell * Rockwell, Maine, a fictional town in ''The Iron Giant'' Brands and enterprises * Rockwell International, a former defense company in the United States, portions of which are now owned by ArvinMeritor, Boeing Integrated Defense Systems, Pratt & Whitney Rocketdyne, and United Technologies ** Rockwell Automation, an industrial automation company that descended from Rockwell International ** Rockwell Collins, a communications and aviation electronics company that also descended from Rockwell International, and now part of United Technologies' Collins Aerospace division. ** Rockwell Semiconductor, a semiconductor company that also descended from Rockwell International, now known as Conexant * Rockwell Diamonds, a mid-tier high-value gem diamond producer based in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bill Mensch
William David Mensch, Jr. (born February 9, 1945) is an American electrical engineer born in Quakertown, Pennsylvania. He was a major contributor to the design of the Motorola 6800 8-bit microprocessor and was part of the team led by Chuck Peddle that created the MOS Technology 6502. He also designed the 16-bit successor to the 6502, the 65816. Mensch is the founder, chairman, and chief executive officer (CEO) of the Western Design Center (WDC) located in Mesa, Arizona. Before founding WDC in 1978, Mensch held design engineering and management positions at Philco-Ford, Motorola, MOS Technology, and Integrated Circuit Engineering. At WDC, Mensch worked mainly on extending and expanding the 6502 architecture. His designs are used widely in embedded systems and implantable, electronic, life-support devices. Education, teaching and honors Mensch graduated with an associate degree (A.S.) from Temple University in 1966 where he was a member of Sigma Pi fraternity. He received his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MOS Technology
MOS Technology, Inc. ("MOS" being short for Metal Oxide Semiconductor), later known as CSG (Commodore Semiconductor Group) and GMT Microelectronics, was a semiconductor design and fabrication company based in Audubon, Pennsylvania. It is most famous for its 6502 microprocessor and various designs for Commodore International's range of home computers. History Three former General Instrument executives, John Paivinen, Mort Jaffe and Don McLaughlin, formed MOS Technology in Valley Forge, Pennsylvania in 1969. The Allen-Bradley Company was looking to provide a second source for electronic calculators and their chips designed by Texas Instruments (TI). In 1970 Allen-Bradley acquired a majority interest in MOS Technology. In the early 1970s, TI decided to release their own line of calculators, instead of selling just the chips inside them, and introduced them at a price that was lower than the price of the chipset alone. Many early chip companies were reliant on sales of cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CSG 65CE02
The CSG 65CE02 is an 8/16-bit microprocessor developed by Commodore Semiconductor Group in 1988. It is a member of the MOS Technology 6502 family, developed from the CMOS WDC 65C02 released by the Western Design Center in 1983. Like the 65C02, the 65CE02 was built on a 2 µm CMOS process instead of the original 6502's 8 µm NMOS logic, NMOS technology, making the chip smaller (and thus less expensive) as well as using much less power. In addition to changes made in the 65C02, the 65CE02 also included improvements to the Instruction pipelining, processor pipeline to allow one-byte instructions to complete in 1 cycle, rather than the 6502's (and most variants) minimum of 2 cycles. It also removed 1 cycle delays when crossing Page (computer memory), page boundaries. These changes improved performance as much as 25% at the same clock speed. Other changes included the addition of a third index register, Z, along with the addition and modification of a number of instructions t ... [...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] |
Zero Flag
The zero flag is a single bit flag that is a central feature on most conventional CPU architectures (including x86, ARM, PDP-11, 68000, 6502, and numerous others). It is often stored in a dedicated register, typically called status register or flag register, along with other flags. The zero flag is typically abbreviated Z or ZF or similar in most documentation and assembly languages. Along with a carry flag, a sign flag and an overflow flag, the zero flag is used to check the result of an arithmetic operation, including bitwise logical instructions. It is set to 1, or true, if an arithmetic result is zero, and reset otherwise. This includes results which are not stored, as most traditional instruction sets implement the compare instruction as a subtract where the result is discarded. It is also common that processors have a bitwise AND-instruction that does not store the result. The logical formula of the zero flag for a twos-complement binary operand is NOT(OR(all bits of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
