What (who) is Motorola 68020 - definition
MICROPROCESSOR MODEL
68020; MC68EC020; Motorola 68EC020; 68EC020; 68020 Microprocessor; MC68020
Motorola 68020
<processor> A microprocessor from Motorola. It was the
successor to the Motorola 68010 and was followed by the
Motorola 68030. The 68020 has 32-bit internal and external
data and address buses and a 256-byte instruction buffer,
arranged as 64 direct-mapped 4-byte entries[? ].
The 68020 added many improvements to the 68010 including a
32-bit ALU and external data bus and address bus, and
new instrucitons and addressing modes. The 68020 (and
68030) had a proper three-stage pipeline.
The new instructions included some minor improvements and
extensions to the supervisor state, some support for
high-level languages which didn't get used much (and was
removed from future 680x0 processors[? ]), bigger (32 x 32-bit)
multiply and divide instructions, and bit field manipulations.
The new adderessing modes added another level of indirection
to many of the pre-existing modes, and added quite a bit of
flexibility to various indexing modes and operations.
The instruction buffer (an instruction cache) was 256
bytes, arranged as 64 direct-mapped 4-byte entries. Although
small, it made a significant difference in the performance of
many applications.
The 68881 and the faster 68882 FPU chips could be used with
the 68020.
The 68020 was used in many models of the Apple Macintosh II
series of personal computers and Sun 3 workstations.
(2001-03-07)
68020
MC68020
Wikipedia
Motorola 68020
The Motorola 68020 ("sixty-eight-oh-twenty", "sixty-eight-oh-two-oh" or "six-eight-oh-two-oh") is a 32-bit microprocessor from Motorola, released in 1984. A lower-cost version was also made available, known as the 68EC020. In keeping with naming practices common to Motorola designs, the 68020 is usually referred to as the "020", pronounced "oh-two-oh" or "oh-twenty".
The 020 was in the market for a relatively short time. The Motorola 68030 was announced in September 1986 and began deliveries in the summer of 1987. Priced about the same as the 020 of the time, the 030 was significantly faster and quickly replaced in 020 in almost every use.
