I can reproduce this bug, but I'm not sure what QEMU is doing wrong. Looking at the "SH4 Software Manual", it definitely says that if the FPSCR.PR bit is 0 then the 'frchg' and 'fschg' instructions should both trap.
The 'frchg' that autogen is hitting is the one in glibc's "getcontext" implementation: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/sh/sh4/getcontext.S;hb=b6d2c4475d5abc05dd009575b90556bdd3c78ad0#l70 QEMU linux-user mode runs with FPSCR=0x000800000, which is "FPSCR.PR == 1", ie "double precision". This seems to match what the kernel has for its FPSCR_INIT value. Are you in a position to test what the actual hardware/real Linux kernel using for its FPSCR value when running sh4 userspace binaries ? -- You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1796520 Title: autogen crashes on qemu-sh4-user after 61dedf2af7 Status in QEMU: Confirmed Bug description: Running "autogen --help" crashes on qemu-sh4-user with: (sid-sh4-sbuild)root@nofan:/# autogen --help Unhandled trap: 0x180 pc=0xf64dd2de sr=0x00000000 pr=0xf63b9c74 fpscr=0x00080000 spc=0x00000000 ssr=0x00000000 gbr=0xf61102a8 vbr=0x00000000 sgr=0x00000000 dbr=0x00000000 delayed_pc=0xf64dd2a0 fpul=0x00000003 r0=0xf6fc1320 r1=0x00000000 r2=0xffff5dc4 r3=0xf67bfb50 r4=0xf6fc1230 r5=0xf6fc141c r6=0x000003ff r7=0x00000000 r8=0x00000004 r9=0xf63e20bc r10=0xf6fc141c r11=0xf63e28f0 r12=0xf63e2258 r13=0xf63eae1c r14=0x00000804 r15=0xf6fc1220 r16=0x00000000 r17=0x00000000 r18=0x00000000 r19=0x00000000 r20=0x00000000 r21=0x00000000 r22=0x00000000 r23=0x00000000 (sid-sh4-sbuild)root@nofan:/# Bi-secting found this commit to be the culprit: 61dedf2af79fb5866dc7a0f972093682f2185e17 is the first bad commit commit 61dedf2af79fb5866dc7a0f972093682f2185e17 Author: Richard Henderson <r...@twiddle.net> Date: Tue Jul 18 10:02:50 2017 -1000 target/sh4: Add missing FPSCR.PR == 0 checks Both frchg and fschg require PR == 0, otherwise undefined_operation. Reviewed-by: Aurelien Jarno <aurel...@aurel32.net> Signed-off-by: Richard Henderson <r...@twiddle.net> Message-Id: <20170718200255.31647-26-...@twiddle.net> Signed-off-by: Aurelien Jarno <aurel...@aurel32.net> :040000 040000 980d79b69ae712f23a1e4c56983e97a843153b4a 1024c109f506c7ad57367c63bc8bbbc8a7a36cd7 M target Reverting 61dedf2af79fb5866dc7a0f972093682f2185e17 fixes the problem for me. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1796520/+subscriptions
