Well, as I wrote, it raises the exception 0 ("Int 0") when it is run on a real hardware... I used the following program to find the error: http://ompldr.org/vYmk4aQ/IDIV_80.zip It prints "Success" and quits when it is run under pure DOS, but it crashes the emulator when it is run under DOSBox. …

Dear developers! I have found a new error in DOSBox. The instruction "idiv" crashes DOSBox completely when trying to divide 0x80000000 on 0xFFFF (-0x80000000 on -1): mov dx, 8000h mov ax, 0 mov bx, 0FFFFh idiv bx The expected behaviour is to raise the exception 0. It seems that the error does not …

The tests were run on an Intel Pentium IV and on a clone of Intel 80186c processor.

According to the logic of the intel docs or the real processors? The question is interesting. Of course, when we run the example on a real processor, we have CF = OF = 0. But if we look through the official documentation of Intel 80186, where this instruction appeared first... There are two tables …

Dear DOSBox developers! I used your nice program for making some tests for a clone of Intel microprocessor. I found that the instruction "imul", the ternary variant, sometimes puts incorrect values into the flags. Example: mov si, 7fffh imul dx, si, 1 DOSBox sets carry flag and overflow flag (CF = …

Dear DOSBox developers! I noticed that if you type keyb ru in the console of DOSBox, you get a confusing message: Keyboard layout ru loaded for codepage 808 It should be written instead of this: Keyboard layout ru loaded for codepage 866 since the default DOS Russian codepage is 866, not 808. It is …