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Motorola MC68010R10 PGA processor

The pin grid array (PGA) version of the 68010 was never used in any Macintosh model.

The Motorola 68010, also referred to as the 68010 or '010, is a 16/32-bit CISC processor that was produced by Motorola's Semiconductor Products Sector as a modestly updated version of the original Motorola 68000.[1] It was succeeded by the Motorola 68020.

Features[]

The 68010 includes a tiny cache to accelerate small loops of two instructions. A design error from the 68000 was fixed so that an optional Motorola 68451 memory management unit (MMU) could add support for virtual memory. However, the 68010 is not 100% software compatible with the 68000. The changes include:

  • The MOVE from SR instruction is privileged in the 68010 and can only be executed in supervisor mode, meeting Popek and Goldberg virtualization requirements. Because the 68000 offers an unprivileged MOVE from SR, it does not meet them.
  • The MOVE from CCR instruction was added to partially compensate for the removal of the user-mode MOVE from SR.
  • It can recover from bus faults, allowing it to implement virtual memory.
  • The exception stack frame is different.
  • It introduced a 22-bit Vector Base Register (VBR), which allowed the vector jump table to be anywhere in up to 4MB addressable RAM. The 68000 vector table was always based at address zero.

History[]

Motorola MC68010L8 DIP processor

The dual in-line package (DIP) version of the 68010 fits the 68000 sockets in early compact Macs.

The 68010 was released in 1982 and is pin-compatible with corresponding packages of the 68000. Despite rumors of a 68010-based "Turbo Mac" in development for 1986,[2] it was not used in any Macintosh model. Enthusiasts who tested it by attaching it to a Dove accelerator board found that a few programs, such as the Calculator desk accessory, would cause a hard crash.[1] This issue also affected the Calculator program of Amiga computers. Aside from compatibility issues, observed speed increases at the same clock speed ranged from 8% to 50%.[3] The 68010 was also found to be drop-in compatible with the Macintosh Plus that had a dual in-line package (DIP) socket soldered in place of the existing 68000 processor. However, real-world speed improvements were found to be minimal.[4]

A third party peripheral that used the 68010 was Jasmine's Direct Serve AppleShare file server, delivering performance comparable to a 68030-based Macintosh IIcx, but without the need of a dedicated Mac.[5]

References[]

  1. 1.0 1.1 Hacks & Modifications » 68010 in a mac? by uniserver, ThinkClassic. 2014-12-11.
  2. Apple working on Turbo Mac for 1986 by Michael McCarthy, InfoWorld. 1985-04-01.
  3. AMIGA Technical Note: Upgrading an AMIGA A1000 with a Motorola MC68010L8 by Thad Floryan, Memphis Amiga Group. 1986-03-29.
  4. Socket to me by Keith Kaisershot, Twitter. 2021-03-05.
  5. Jasmine AppleShare File Server Ships With Faster Performance by Laurie Flynn, InfoWorld. 1989-10-02.

External links[]

Motorola 68k series processors
Central processing units : 68000 · 68010 · 68020 · 68030 · 68040 · 68050 · 68060
Floating-point units :   (n/a)  ·   (n/a)  · 68881 · 68882 · (SANE)
Memory management units :   (n/a)  · 68451 · 68851
Other :                           (VI475)
Superseded by PowerPC processors in March 1994
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