Motorola 68010
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The Motorola MC68010 processor is a 16/32-bit microprocessor from Motorola, made in the early 1980s.
It is largely similar to the Motorola 68000 CPU with the exception of the addition of several instructions for breakpoint and register control (ccr instead of sr), as well as the ability to save all of the processor state on an interrupt and exception. This made it possible to use the processor for virtual memory applications, for which the 68000 was unsuited (in detail: Contrary to the 68000 the 68010 was able to handle a double bus fault).
Additionally, the 68010 had a "loop mode", i.e. a mini instruction cache, which accelerates loops that consist of only 2 instructions. But the overall speed gain compared to the 68000 was below 10% in practice, so it did not make much sense to upgrade the 68000 CPU with its pin compatible successor.
The 68010 was not 100% software compatible with the 68000. The most problematic difference was the exception stack frame.
The 68010 could be used with the 68451 MMU, but problems with the design, in particular a 1 clock memory access penalty made this configuration unpopular.and lead to other vendors such as Sun Microsystems using their own MMU design.
The 68010 was never as popular as the 68000 as the added complexity and cost turned out to not be worthwhile in practice. Most vendors looking for the MMU functionality waited for the 68020 instead. However due to a small speed boost over the 68000, it can be found in a number of Unix workstations and research machines.
The 68010 had a feature useful to hackers. The Vector Base Register (VBR) allows the exception vectors to be moved from low memory to an arbitrary location. A monitor/debugger program can intercept the interrupts, and maintain the ability to activate on demand even if the low-memory vectors are modified.
External links
- 68010 images and descriptions at cpu-collection.de (http://www.cpu-collection.de/?tn=1&l0=cl&l1=68010)
| List of Motorola microprocessors |
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The 6800 family |
6809 (see also:
Hitachi 6309) |
68000 family:
68000 |
68008 |
68010 |
68012 |
68020 |
68030 |
68040 |
68060 |
Coldfire |
Dragonball |
Pre-PPC RISC: 88000 |
Floating-point processors: 68881 |
68882
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