[Qemu-devel] [5403] Do not use load_seg_vm to load CS in real mode iret handling

[Qemu-devel] [5403] Do not use load_seg_vm to load CS in real mode iret handling

[malc]

Revision: 5403
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5403
Author:   malc
Date:     2008-10-02 20:02:27 +0000 (Thu, 02 Oct 2008)

Log Message:
-----------
Do not use load_seg_vm to load CS in real mode iret handling

load_seg_vm calls cpu_x86_load_seg_cache which updates hflags of
current env, real hardware doesn't do this, nor the code that handles
real mode lret/lcall/ljmp.

This unbreaks "unreal mode" and makes QEMU the first emulator being
able to run Project Angel demo by IMPACT Studios. (Not that there are
many physical machines out there capable of doing the same)

Modified Paths:
--------------
    trunk/target-i386/op_helper.c

Modified: trunk/target-i386/op_helper.c
===================================================================
--- trunk/target-i386/op_helper.c	2008-10-02 19:55:50 UTC (rev 5402)
+++ trunk/target-i386/op_helper.c	2008-10-02 20:02:27 UTC (rev 5403)
@@ -2651,7 +2651,8 @@
         POPW(ssp, sp, sp_mask, new_eflags);
     }
     ESP = (ESP & ~sp_mask) | (sp & sp_mask);
-    load_seg_vm(R_CS, new_cs);
+    env->segs[R_CS].selector = new_cs;
+    env->segs[R_CS].base = (new_cs << 4);
     env->eip = new_eip;
     if (env->eflags & VM_MASK)
         eflags_mask = TF_MASK | AC_MASK | ID_MASK | IF_MASK | RF_MASK | NT_MASK;