Motorola 68010
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The Motorola MC68010 processor is a 16/32-bit microprocessor from Motorola, released in 1982 [1]. In common with the Motorola 68000 naming convention, it is usually just referred to as the 010 (pronounced oh-one-oh).
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; specifically, contrary to the 68000, the 68010 was able to handle a double bus fault.
Additionally, the 68010 had a "loop mode", considered a mini instruction cache, which accelerates loops that consist of only 2 instructions. 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 the 68010, even though the two were pin-compatible.
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 led 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. Due to the 68010's small speed boost over the 68000, though, it can be found in a number of Unix workstations and research machines, and it was used sometimes to add a small boost to Atari ST and Amiga computers.
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.
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| List of Motorola/Freescale microprocessors | |
|---|---|
| The 6800 family : | 6809 (see also: Hitachi 6309) |
| 68000 family : | 68000 | 68008 | 68010 | 68012 | 68020 | 68030 | 68040 | 68060 | ColdFire | DragonBall |
| Low-cost variants: | 68EC000 | 68EC020 | 68EC030 | 68EC040 | 68LC040 |
| Pre-PowerPC RISC : | 88000 |
| Floating-point coprocessors : | 68881, 68882 |
| PowerPC family : | PPC 75x ("PowerPC G3") | PPC 74xx ("PowerPC G4") | PowerQUICC |
