STERNLIGHT@USC-ECL.ARPA (09/05/84)
I have a FORTRAN program which is supposed to test to see if there is an 8087 present, and if so, use it. If not, it is supposed to use the 8088 for arithmetic. It is compiled in Microsoft (IBM/Microsoft) FORTRAN and works fine on the PC, PC Portable, and PC-XT. In running it on the AT, if an 80287 is installed it works fine. If not, all numbers are displayed as 1.0. Has anyone encountered this? What is the cause, the 80286 or the software? I understand Lifeboat C has a similar problem. Does IBM know about it? Is it to be fixed? --david--
mike@smu.UUCP (09/20/84)
<> I'm not sure how your FORTRAN proogram worked, but it probably did something flakey to detect whether an 87 was in place. The 8086 should not really be able to figure this out. Because the processor/coprocessor interface between the 286 and 287 is so much different than that between the 86 and 87, I am not surprised that it does not work. The 286 does have the capability of trapping upon recognition of an ESC instruction via a couple of bits in the MSW. I have heard, however, that current AT software doesn't support that kind of thing. Mike McNally ...convex!smu!mike