** Attachment removed: "my operating system" https://bugs.launchpad.net/qemu/+bug/1902267/+attachment/5429520/+files/FLATDOS.IMG
** Attachment added: "my operating system" https://bugs.launchpad.net/qemu/+bug/1902267/+attachment/5429530/+files/FLATDOS.IMG -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1902267 Title: CPU not support 32-bit stack in 32-bit unreal mode Status in QEMU: New Bug description: QEMU version 5.0.0 supports 32-bit and 16-bit unreal mode. Great! Unfortunately, QEMU does not support 32-bit stack in unreal 32-bit mode. After the INT instruction, the stack is switched to 16-bit, which should not be the case. At BOCHS, my code works 100%. At QEMU not works. Sample code to find out: use32 cli mov ax,cs shl eax,16 mov ax,NewInt80h mov [IDT32+4*80h],eax mov edx,esp mov esp,0x10000 int 80h NewInt80h: xchg esp,edx cmp edx,0x10000-6 jnz IsStack16Bit Stack selector loaded from GDT: GDT: real32_GDT dq 0 dw 0xFFFF,0x0000,9A00h,0xCF ; 32-bit code descriptor dw 0xFFFF,0x0000,9200h,0x8F ; 4 GB data descriptor dw 0xFFFF,0x0000,9A00h,0x00 ; 16-bit code descriptor dw 0xFFFF,0x0000,9200h,0xCF ; 32-bit data descriptor stack To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1902267/+subscriptions
