From e60b597af5cd2c7a61faaa018a39eec9ed8714d5 Mon Sep 17 00:00:00 2001
From: Christian Helmuth <christian.helmuth@genode-labs.com>
Date: Tue, 21 May 2019 17:13:24 +0200
Subject: [PATCH] linux: 32-bit compatibility with GCC versions before 7

GCC version 7 and above generate calls to __divmoddi for 64bit integer
division on 32-bit. Unfortunately, libgcc liberaries of older compilers
lack this symbol and are still in use by Debian/Ubuntu LTS at least.
---
 repos/base-linux/lib/mk/lx_hybrid.mk        |  2 +
 repos/base-linux/src/lib/lx_hybrid/libgcc.c | 73 +++++++++++++++++++++
 2 files changed, 75 insertions(+)
 create mode 100644 repos/base-linux/src/lib/lx_hybrid/libgcc.c

diff --git a/repos/base-linux/lib/mk/lx_hybrid.mk b/repos/base-linux/lib/mk/lx_hybrid.mk
index 77686587b2..43f93b6ee1 100644
--- a/repos/base-linux/lib/mk/lx_hybrid.mk
+++ b/repos/base-linux/lib/mk/lx_hybrid.mk
@@ -1,8 +1,10 @@
 SRC_CC += lx_hybrid.cc new_delete.cc capability_space.cc
 SRC_CC += signal_transmitter.cc signal.cc
+SRC_C  += libgcc.c
 
 vpath new_delete.cc $(BASE_DIR)/src/lib/cxx
 vpath lx_hybrid.cc   $(REP_DIR)/src/lib/lx_hybrid
+vpath libgcc.c       $(REP_DIR)/src/lib/lx_hybrid
 
 # add parts of the base library that are shared with core
 LIBS += base-linux-common timeout
diff --git a/repos/base-linux/src/lib/lx_hybrid/libgcc.c b/repos/base-linux/src/lib/lx_hybrid/libgcc.c
new file mode 100644
index 0000000000..d3fd12093a
--- /dev/null
+++ b/repos/base-linux/src/lib/lx_hybrid/libgcc.c
@@ -0,0 +1,73 @@
+/*
+ * \brief  libgcc contrib code for lx-hybrid components
+ * \author Christian Helmuth
+ * \date   2019-05-21
+ *
+ * GCC version 7 and above generate calls to __divmoddi for 64bit integer
+ * division on 32-bit. Unfortunately, libgcc liberaries of older compilers
+ * lack this symbol and are still in use by Debian/Ubuntu LTS at least.
+ *
+ * Implementation is similar to GCC 8.3 libgcc/libgcc2.c and libgcc/libgcc2.h -
+ * original license header follows.
+ */
+/* Copyright (C) 1989-2016 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+#ifdef __i386__
+typedef int          SItype  __attribute__ ((mode (SI)));
+typedef int          DItype  __attribute__ ((mode (DI)));
+typedef unsigned int UDItype __attribute__ ((mode (DI)));
+typedef SItype  Wtype;
+typedef DItype  DWtype;
+typedef UDItype UDWtype;
+struct DWstruct { Wtype low, high; };
+typedef union { struct DWstruct s; DWtype ll; } DWunion;
+
+extern UDWtype __udivmoddi4 (UDWtype, UDWtype, UDWtype *);
+
+DWtype __divmoddi4 (DWtype u, DWtype v, DWtype *rp)
+{
+  Wtype c1 = 0, c2 = 0;
+  DWunion uu = {.ll = u};
+  DWunion vv = {.ll = v};
+  DWtype w;
+  DWtype r;
+
+  if (uu.s.high < 0)
+    c1 = ~c1, c2 = ~c2,
+    uu.ll = -uu.ll;
+  if (vv.s.high < 0)
+    c1 = ~c1,
+    vv.ll = -vv.ll;
+
+  w = __udivmoddi4 (uu.ll, vv.ll, (UDWtype*)&r);
+  if (c1)
+    w = -w;
+  if (c2)
+    r = -r;
+
+  *rp = r;
+  return w;
+}
+#endif
+