Editing Motorola 68010

{{Short description|Microprocessor model}}
{{Infobox CPU
| name          = Motorola 68010/68012
| designfirm    = Motorola
| produced-start= 1982
| slowest       = 8
| slow-unit     = MHz
| fastest       = 16.67
| fast-unit     = MHz
| arch          = [[Motorola 68000 series]]
| data-width    = 16 bits
| address-width = MC68010: 24 bits{{br}}MC68012: 31 bits
| transistors   = 69,000<ref>{{cite journal |title=i486, 68040 Use Pipelining To Speed Up Performance |journal=InfoWorld |date=May 8, 1989 |page=39 |url=https://books.google.com/books?id=RzoEAAAAMBAJ&pg=PT38}}</ref>
| predecessor   = [[Motorola 68000]]
| successor     = [[Motorola 68020]]
|pack1=64-pin [[Dual in-line package|DIP]]<ref name=datasheet />
|pack2=68-pin [[Pin grid array|PGA]]<ref name=datasheet />
|pack3=68-pin [[Quad flat pack|Quad Pack]]<ref name=datasheet />
|pack4=84-pin PGA (MC68012)<ref name=datasheet />
}}
[[Image:KL Motorola 68010 DIP.jpg|upright|thumb|Motorola 68010 as DIP]]
[[Image:KL Motorola 68010 PGA.jpg|upright|thumb|Motorola 68010 as PGA]]
The '''Motorola MC68010''' and '''Motorola MC68012''' are 16/32-bit [[microprocessor|microprocessors]] from [[Motorola]], released in 1982 as successors to the [[Motorola 68000]].<ref>{{cite web| url = http://www.cpu-world.com/CPUs/68010/| title = Motorola 68010 (MC68010) family| website = CPU World}}</ref> The 68010 and 68012 added virtualization features, optimized loops and fixed several small flaws to the 68000. The MC68010 variants were [[Pin compatibility|pin compatible]] with its predecessor while the MC68012 is an 84-pin [[pin grid array|PGA]] version with its directly accessible memory space extended to 2&nbsp;[[gigabyte|GiB]].<ref name=datasheet>{{cite book |url=http://bitsavers.org/components/motorola/68000/68010_68012_Data_Sheet_May85.pdf |title=MC68010/MC68012 16-/32-Bit Virtual Memory Microprocessors |date=May 1985 |publisher=Motorola Semiconductor |archive-url=https://web.archive.org/web/20200328171347/http://bitsavers.org/components/motorola/68000/68010_68012_Data_Sheet_May85.pdf |archive-date=2020-03-28 |url-status=live}}</ref><ref>{{cite book |last1=Avtar |first1=Singh |title=16-Bit and 32-Bit Microprocessors: Architecture, Software, and Interfacing Techniques |last2=Triebel |first2=Walter A. |publisher=[[Prentice-Hall]] |year=1991 |isbn=978-0138121570 |location=Englewood Cliffs, New Jersey}}</ref>

== Differences between 68010/68012 and 68000 ==
The 68010 and 68012 are completely user-mode compatible with the 68000, except that the MOVE from SR instruction traps in user mode, so that, to support user-mode code using that instruction, a supervisor-mode trap handler must simulate the instruction and continue the user-mode code after that instruction. This was done so that the 68010 and 68012 would meet the [[Popek and Goldberg virtualization requirements]], specifically that a new OS could run as guest and not be aware.{{r|datasheet|at=§1.3.2}} A new unprivileged MOVE from CCR instruction was added to compensate for the penalty of trapping user-mode MOVE from SR.

The 68010 and 68012 can recover from bus faults, and continue the faulting instruction, allowing them to implement [[virtual memory]]. This means that the exception stack frame is different.

A 32-bit Vector Base Register (VBR) holds the base address for the [[Exception handling|exception]] vector table. The 68000 vector table was always based at address zero.

A "loop mode" accelerates loops consisting of only a "loopable" instruction and a DBcc (Decrement/Branch on condition); an example would be MOVE and DBRA. The two-instruction mini-loop opcodes are prefetched and held in the 6-byte instruction cache while subsequent memory read/write cycles are only needed for the data operands for the duration of the loop.{{r|datasheet|at=§7.1.3}} It provided for performance improvements averaging 50%, as a result of the elimination of instruction opcodes fetching during the loop.

[[File:Motorola MC68012 0988.jpg|upright|thumb|Motorola 68012]]
[[File:Motorola MC68012 die.JPG|upright|thumb|[[Die (integrated circuit)|Die]] of Motorola 68012]]{{Anchor|Motorola 68012}}The MC68012 variant, in addition to its memory space being extended to 2&nbsp;GiB, also added a [[read-modify-write]] cycle (RMC) pin, indicating that an indivisible read-modify-write cycle in progress, in order to help the design of multiprocessor systems with virtual memory.

The expansion of the memory space in the 68012 caused an issue for any programs that used the high byte of an address to store data, a programming trick that was successful with those processors that only have a 24-bit address bus (68000 and 68010). A similar problem affected the [[68020]].

== Usage ==
[[Image:MC68451 p1160081.jpg|thumb|upright|Motorola 68451 MMU]]
The 68010 could be used with the [[Motorola 68451|68451]] [[Memory management unit|MMU]]. However, aspects of its design, such as its 1 [[Clock signal|clock]] [[computer storage|memory]] access penalty, made this configuration unpopular. Some vendors used their own MMU designs, such as [[Sun Microsystems]] in their [[Sun-2]] [[workstation]] and [[Convergent Technologies]] in the [[AT&T Corporation|AT&T]] [[AT&T UNIX PC|UNIX PC/3B1]].

The 68010 was never as popular as the 68000 when it was available. However, because of the 68010's small speed boost over the 68000 and its support for virtual memory, it can be found in a number of smaller [[Unix]] systems, both with the 68451 MMU (for example in the [[Torch Triple X]]), and with a custom MMU (such as the Sun-2 workstation, AT&T UNIX PC/3B1, Convergent Technologies MiniFrame, Plexus P/15 and P/20,<ref>{{Cite web |date=1985 |title=Plexus P/15-P/20 Brochure |url=https://usermanual.wiki/Document/PlexusP15P20Brochure1985.1864982809/view |access-date=2024-05-28 |website=UserManual.wiki |publisher=Plexus Computers, Inc. |format=PDF}}</ref> [[NCR Corporation|NCR]] Tower XP, [[Apollo Computer]]'s [[Apollo/Domain|DN300 and DN320]],<ref>{{cite web|url=http://www.bitsavers.org/pdf/apollo/002685-07_Technical_Publications_Overview_Jun87.pdf|title=Apollo Computer Technical Publications Overview|date=June 1987|publisher=Apollo Computer|access-date=2022-10-13}}</ref> and [[HP 9000]] Model 310), as well as various research machines. Most other vendors (such as [[Apple Inc.|Apple Computer]]) stayed with the 68000 until the [[Motorola 68020|68020]] was introduced.

[[Atari Games]] used the 68010 in some of their arcade boards such as the [[Atari System#Atari System 1|Atari System 1]].

Some owners of [[Amiga]] and [[Atari ST]] computers as well as the [[Sega Genesis]] game consoles replaced their system's 68000 CPU with a 68010 to gain a small speed boost.<ref>{{cite web |url=http://www.memphisamigagroup.net/diskmags/198803/68010-kit/MC68010.ins |title=AMIGA (tm) TECHNICAL NOTE Upgrading an AMIGA A1000 with a Motorola MC68010L8 |first=Thad |last=Floryan}}</ref><ref>{{cite web|url=https://mode5.net/68010mod.html|title=Genesis 68010 mod|website=mode5.net}}</ref> In practice, the overall speed gain over a 68000 at the same frequency is less than 10%.

== References ==
<references/>

== External links ==
* [http://www.cpu-collection.de/?tn=1&l0=cl&l1=68010 68010 images and descriptions at cpu-collection.de]

{{Motorola processors}}

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[[Category:68k microprocessors]]
[[Category:Computer-related introductions in 1982]]
[[Category:32-bit microprocessors]]