** Tags added: arm -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1922887
Title: STR in Thumb 32 decode problem Status in QEMU: New Bug description: Hi It seems that QEMU does not have a proper check on the STR instruction in Thumb32 mode. Specifically, the machine code is 0xf84f0ddd, which is 0b1111 1000 0100 1111 0000 1101 1101 1101. This is an STR (immediate, Thumb) instruction with a T4 encoding scheme. The symbols is Rn = 1111 Rt = 0000 P = 1 U = 0 W = 1 The decode ASL is below: if P == ‘1’ && U == ‘1’ && W == ‘0’ then SEE STRT; if Rn == ‘1101’ && P == ‘1’ && U == ‘0’ && W == ‘1’ && imm8 == ‘00000100’ then SEE PUSH; if Rn == ‘1111’ || (P == ‘0’ && W == ‘0’) then UNDEFINED; t = UInt(Rt); n = UInt(Rn); imm32 = ZeroExtend(imm8, 32); index = (P == ‘1’); add = (U == ‘1’); wback = (W == ‘1’); if t == 15 || (wback && n == t) then UNPREDICTABLE; When Rn == 1111, it should be an undefined instruction, which should raise SEGILL signal. However, it seems that QEMU does not check this constraint, which should be a bug. Many thanks Regards Muhui To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1922887/+subscriptions
