Motorola 68010


Motorola 68010

(processor)A microprocessor from Motorola. It was thesuccessor to the Motorola 68000 and was followed by theMotorola 68020. Some instructions which were previouslyuser mode were made system mode, which necessitatedpatches to a few programs.

The 68010's main advantage over the 68000 was that it couldrecover from a bus fault. The 68000 microcode didn't saveenough state to restart all instructions; the 68010 correctedthis fault. This allowed it to use paged virtual memory.

The 68010's DBxx (decrement and branch) instructions couldhold and execute the preceding instruction in the prefetch buffer, allowing some two-instruction loops to executewithout refetching instructions.

At one time there was a 68010 variant that was pin-for-pincompatible with the 68000. Early Amiga hackers replacedtheir 68000s with 68010s in order to get a small performanceincrease.