We have run into a problem with preserving the floating point unit contents during interrupt handling. We are using 2.0.35 linux and the 0.9 rtl kernal on a 90MHz pentium. The FSAVE assembly instruction is taking from 1 to 400 usecs to save the contents of the floating point unit. Our data sheets for the old 387 FP unit showed a worst case of 400 clock cycles for the longest FP instruction and 100 cycles for the FSAVE instruction. We figure on a worst case of 500 cycles at 90MHz to give 5.5 usecs. We must have gone wrong somewhere. Is there a cache write through problem occuring as well? Has anyone come accross this problem or have any ideas on what's happening? Any assistance greatly appreciated. Thanks, Reg Dunlop --- [rtl] --- To unsubscribe: echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED] ---- For more information on Real-Time Linux see: http://www.rtlinux.org/~rtlinux/
