From d5738a574daee265ebfcf28dd51dfdca56c1798b Mon Sep 17 00:00:00 2001
From: Michael Weiser <michael.weiser@gmx.de>
Date: Tue, 13 Feb 2018 22:13:12 +0100
Subject: [PATCH] Add arm endianness-aware assembly infrastructure

Introduce m4 macros to conditionally handle differences of little- and
big-endian arm in assembler code.
---
 asm.m4       | 8 ++++++++
 config.m4.in | 1 +
 configure.ac | 7 ++++++-
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/asm.m4 b/asm.m4
index 4018c235..8da47201 100644
--- a/asm.m4
+++ b/asm.m4
@@ -51,6 +51,14 @@ define(<ALIGN>,
 <.align ifelse(ALIGN_LOG,yes,<m4_log2($1)>,$1)
 >)
 
+define(<IF_BE>, <ifelse(
+WORDS_BIGENDIAN,yes,<$1>,
+WORDS_BIGENDIAN,no,<$2>,
+<errprint(<Unsupported endianness value>,WORDS_BIGENDIAN,<
+>)
+  m4exit(1)>)>)
+define(<IF_LE>, <IF_BE(<$2>, <$1>)>)
+
 dnl Struct defining macros
 
 dnl STRUCTURE(prefix) 
diff --git a/config.m4.in b/config.m4.in
index e39c880c..11f90a40 100644
--- a/config.m4.in
+++ b/config.m4.in
@@ -7,6 +7,7 @@ define(<TYPE_PROGBITS>, <@ASM_TYPE_PROGBITS@>)dnl
 define(<ALIGN_LOG>, <@ASM_ALIGN_LOG@>)dnl
 define(<W64_ABI>, <@W64_ABI@>)dnl
 define(<RODATA>, <@ASM_RODATA@>)dnl
+define(<WORDS_BIGENDIAN>, <@ASM_WORDS_BIGENDIAN@>)dnl
 divert(1)
 @ASM_MARK_NOEXEC_STACK@
 divert
diff --git a/configure.ac b/configure.ac
index 0a35d3dd..a3460853 100644
--- a/configure.ac
+++ b/configure.ac
@@ -205,7 +205,11 @@ LSH_FUNC_STRERROR
 # getenv_secure is used for fat overrides,
 # getline is used in the testsuite
 AC_CHECK_FUNCS(secure_getenv getline)
-AC_C_BIGENDIAN
+
+ASM_WORDS_BIGENDIAN=unknown
+AC_C_BIGENDIAN([AC_DEFINE([WORDS_BIGENDIAN], 1)
+		ASM_WORDS_BIGENDIAN=yes],
+	[ASM_WORDS_BIGENDIAN=no])
 
 AC_CACHE_CHECK([for __builtin_bswap64],
 		nettle_cv_c_builtin_bswap64,
@@ -820,6 +824,7 @@ AC_SUBST(ASM_TYPE_PROGBITS)
 AC_SUBST(ASM_MARK_NOEXEC_STACK)
 AC_SUBST(ASM_ALIGN_LOG)
 AC_SUBST(W64_ABI)
+AC_SUBST(ASM_WORDS_BIGENDIAN)
 AC_SUBST(EMULATOR)
 
 AC_SUBST(LIBNETTLE_MAJOR)
-- 
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