View allAll Photos Tagged retrocomputing
AMD produced what is probably the first floating point "coprocessor" for microprocessors, the AMD 9511 "arithmetic circuit" (1979), which performed 32 bit (23 + 7 bit floating point) RPN-style operations (4 element stack) under CPU control.
________________________________________________________________
AM9511 APU (arithmetic processing unit) performs floating point calculations that would be too time-consuming or cumbersome if done on Z80 microprocessor.
In addition to the four basic operations, the 9511 can implement transcendental functions (sin, log, etc.), and it can also perform conversion from floating point to fixed point and vice versa. It can also perform operations in 16 or 32 bit fixed point two's complement integer representation.
The fastest instruction is 16 bit fixed point addition which takes 4 microsec, the slowest instruction is arc-tangent which takes almost 2 milisec; 32 bit floating point addition takes 14-87 microsec.
The 9511 is an autonomous processor: it acts like a peripheral and it in not tied to any particular microcrocessor. AM9511 is configured as a pair of I/O ports with the capability of causing the Z80 to pause for completion of the processor's operation if it has not been completed by the time the Z80 code requires the results.
The 9511 is a stack orientaded processor. Operands are first pushed onto the internal stack, and then a comand is issued to the processor to perform an operation on the stack. Results are removed from the stack.
All transfers, including operands, results, status and command information, take place over an 8-bit bidirectional data bus. The internal data paths and the internal ALU are 16 bits wide, even though some operations are on 32 bits operands (this fact indicates that extending the 9511 to handle double precision format could have been implemented internally quite easily). The transcendental functions are evaluated using Chebyshev Polynomials which provide an even distribution of errors within the selected data representation.
The 9511 was in 1980's an high cost device: the APU was far more complex than the CPU and the volume of sales was not so high. As a result this was reflected in the price: in 1983 the Am9511@2Mhz cost £90 (considering inflation it would cost £240 now in 2009), the 3Mhz £123.75, the 4Mhz £146.25 ..
The sign next to the base of the machine reads as follows (as near as I can tell, it's a bit fuzzy -- I've put guesses about the text in italics):
[quote]
CADR - The LISP Machine
(late 1970s)
The LISP machine was the first hardware implementation of the AI programming language LISP. Researchers had long been frustrated by the constraints of running LISP programs on large mainframes. They developed LISP machines as stand alone, single user, high-performance computers that could run LISP programs faster and more efficiently. The first machines were hand assembled by Richard Greenblatt at the MIT AI Lab in the mid-1970s. This CADR machine was the basis of commercial products sold by two companies, LISP Machines, Inc founded by Richard Greenblatt, and Symbolics, founded by an ex-administrator of the AI Lab Russell Noftsker. The story of these two companies is typical. While successful in the mid-1980s, the advent of powerful microcomputers that could run LISP programs at similar speeds drove both companies into bankruptcy, LISP in 1987 and Symbolics in 1995.
[/quote]
Questo divisorio è interamente costituito da involucri originali di cassette di giochi anni '80. Almeno tre quarti di questi nomi mi sono noti...
This screen is entirely composed with original cases of '80s video game cassettes. At least three quarters of these names are known to me...
MK3880P-10 (Z80 CPU)
§ Purple Ceramic
§ 2.5 MHz
§ -40° to +85°C
§ Data code: 1980
Here is protected by a transparent plexiglass window
Mostek cut a deal with a startup Zilog, in which Mostek provided fab resources to manufacture the Zilog microprocessors in return for second sourcing rights to the Zilog family. Mostek produced MK3880, the Zilog Z80 and a series of Z80 support chips, until Zilog built their own fab.
MK3880P-10 (Z80 CPU)
§ Purple Ceramic
§ 2.5 MHz
§ -40° to +85°C
§ Data code: 1980
Here is protected by a transparent plexiglass window
Mostek cut a deal with a startup Zilog, in which Mostek provided fab resources to manufacture the Zilog microprocessors in return for second sourcing rights to the Zilog family. Mostek produced MK3880, the Zilog Z80 and a series of Z80 support chips, until Zilog built their own fab.