There is no way to add a coprocessor to a 68040 chip the instructions are never brought out of the chip itself. Because the FPU is "built-in," as it were, the 68040 chip handles instructions that start with an operation word beginning with the hex value F by itself. The rest of the FPU routines are automatically emulated by software. Not everything in the 68881/68882 FPU is in the 68040 chip, however just the routines that Motorola determined were most frequently used. The 68040 microprocessor has most of the 68882 FPU included on the chip. With the introduction of the 6800LC chips, things got a bit more complicated. For these machines, it was possible to purchase an optional card with an FPU coprocessor. Other 680x0-based Macintosh computers, such as the Macintosh IIsi and the Macintosh Color Classic, had an optional FPU coprocessor. NOTE: Some Macintosh models, such as the Macintosh SE/30, the Macintosh IIci, and the Macintosh IIfx, shipped with an FPU coprocessor installed. A program only using SANE would never have an instruction starting with the hex value F. Such programs would have instructions in the program which start with the hex value F. These instructions always start with an operation word beginning with the hex value F.Ī program can be compiled to take advantage of the hardware assistance the FPU provides, and thus yield faster floating-point calculations than would be available with SANE (the Standard Apple Numerics Package). This chip, the Floating Point Unit (FPU), communicates with the CPU via a special set of instructions called F-line instructions. The Motorola 680x0 architecture was originally designed to support a floating- point coprocessor chip. This instruction starts with the hex value F. This instruction starts with the hex value 1.
(There are also external memory management units (MMUs) and other specialized coprocessors.) Motorola 680x0 CPUs use instructions starting with hex value F as instructions for these coprocessors.Īll Motorola 680x0 microprocessors have instructions consisting of at least one word (the operation word) some instructions can have up to eleven words (see the Motorola MC68020 32-bit Microprocessor User's Manual, Third edition, page 3-1.) The operation word determines what kind of instruction is to be executed. The Motorola 680x0 family uses an external floating-point unit. The PowerPC chip has floating point support built in, but that floating-point support is different from the Motorola 680x0 family floating- point support. On a Power Macintosh, No FPU Installed means that some program has jumped to an area of data and has tried to execute any data word starting with the hex value F. No FPU Installed is equivalent to a Type 10 Error i.e., your program has attempted to execute an unknown instruction op code starting with the hex value F. Somewhere in that data (which is being interpreted as instructions) is an instruction whose op code begins with the hex value F. On a Power Macintosh computer, the error message No FPU Installed usually means your code has jumped to a non-code area and is executing garbage. Perhaps you may find an appropriate tool to meet your development needs in this way. There are many Web sites on the Internet for example, Apple's Third-Party Development Products Database at lists many Macintosh development tools. reviews in technical magazines to find a product that fits your needs.Macintosh Development Tools & Languages.You should consult catalogs of development tools such as: DTS doesn't evaluate third-party tools, nor maintain complete lists of possible third-party solutions. If a third-party product is mentioned by name, it's meant to be a possible solution for you to investigate, not a recommendation. NOTE: In this Technote, I will occasionally mention third-party products by name. The Type 11 error is any error (such as a bus error) in native code. The No FPU Installed error usually means that your program is executing data rather than instructions. Both error messages are the result of programming errors. It also focuses on what you as a programmer can do to prevent such errors.īoth Type 11 and No FPU Installed errors occur on Power Macintosh computers, depending on various factors.
This Technote explains some of the causes of "Type 11" and "No FPU Installed" errors, along with debugging hints to help you find and fix them. Type 11 Technote Power Macintosh: Type 11 & No FPU Errors Technote (7/96)
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