If your computer includes an 80387 math coprocessor, it is automatically detected and supported by SCO OpenServer. These coprocessors improve the efficiency of floating point calculations. Pentium, 80486DX2, and 80486DX CPUs include an on-chip floating point unit that is recognized and used as a floating point coprocessor. 80386DX, 80386SX, and 80486SX CPUs do not include a on-chip floating point unit.
If you are going to upgrade your system to include a math coprocessors, it is important to choose one which matches your machine's CPU speed. Follow the manufacturer's recommendations.
At boot time, SCO OpenServer announces the presence of a math coprocessor with the message:
%fpu - 13 - TYPE=80387Note that switches on the main system board must be set properly to enable 80387 interrupts, and/or your system must be reconfigured with the manufacturer's setup disk. Ensure that the system diagnostics recognize the coprocessor's presence, and check your hardware manual for the proper switch settings.
On some motherboards, the operating system incorrectly recognizes the presence of an 80387 coprocessor even if the chip is not installed. This problem is prevalent on machines that use the Intel 302 motherboard. If your computer incorrectly recognizes the presence of an 80387 chip, make sure that blocks E48 and E49 are not connected with a jumper.
Some 80387 exceptions are masked. Refer to the fp(HW) manual page for more details.