TITLE
    Macintosh: "Bad F-line Instruction" Error
Article ID:
Created:
Modified: 		8709
9/20/91
7/1/99
TOPIC

    I am getting a "Bad F-line Instruction" errors on my 68k Macintosh computer. What causes these errors?

DISCUSSION

    In System 7.x, the "Bad F-line Instruction" error is also referred to as the "Co-processor Not Installed" or "No FPU Installed" error; in System 6.0.7 it is referred to as the ID=10 error.

    F-Line instructions are used to access attached processors, such as a floating-point math co-processor. A bad F-Line instruction is a bad Floating Point Unit (FPU) call. However, when you see this on computers without FPUs, or in applications that do not support an FPU, then it is probably a spurious error. These messages often indicate software related errors generated by a program that has extraneous program code. On very rare occasions a hardware failure generates these errors.

    With System 6.0.7, these errors do not have a direct relationship with floating point co-processors; you will not resolve this error by installing an FPU. In System 7.x, there may be a problem with the math chip, or it may be an unrelated software error.

    The error may be caused by bad code in the application which is calling a processor that is not present or calling a memory location that is not there. There may be a corrupted application or an extension causing some spurious memory problem.

    A possible solution is to remove and reinstall the application and/or remove and reinstall the system software.

    NOTE: On Power Macintosh computers, there may be additional causes to these types of errors. See the Tech Info articles, "Power Macintosh Computers: No FPU Installed Error" and "Power Macintosh: Type 11 & No FPU Errors Technote" for additional information.

Document Information
Product Area: Mac OS System Software
Category: General OS
Sub Category: General Topics

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