Initial config for s390x, contributed by Mamone Tarsha.

* configure.ac: Add flag --enable-s390x-msa-x1. Add ABI check for
s390x, and setup asm_path.
* Makefile.in (distdir): Add s390x directory.
* s390x/README: New file

4 files changed, 93 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index c122d40d..ad2b10f2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2021-03-28  Niels Möller  <nisse@lysator.liu.se>
+
+	Initial config for s390x, contributed by Mamone Tarsha.
+	* configure.ac: Add flag --enable-s390x-msa-x1. Add ABI check for
+	s390x, and setup asm_path.
+	* Makefile.in (distdir): Add s390x directory.
+	* s390x/README: New file
+
 2021-03-24  Niels Möller  <nisse@lysator.liu.se>
 
 	* .gitlab-ci.yml: Add remote tests for s390x.
diff --git a/Makefile.in b/Makefile.in
index 0ace35f7..868afdd7 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -617,7 +617,8 @@ distdir: $(DISTFILES)
 		x86_64 x86_64/aesni x86_64/sha_ni x86_64/fat \
 		arm arm/neon arm/v6 arm/fat \
 		arm64 arm64/crypto arm64/fat \
-		powerpc64 powerpc64/p7 powerpc64/p8 powerpc64/fat ; do \
+		powerpc64 powerpc64/p7 powerpc64/p8 powerpc64/fat \
+		s390x ; do \
 	  mkdir "$(distdir)/$$d" ; \
 	  find "$(srcdir)/$$d" -maxdepth 1 '(' -name '*.asm' -o -name '*.m4' -o -name README ')' \
 	    -exec cp '{}' "$(distdir)/$$d" ';' ; \
diff --git a/configure.ac b/configure.ac
index 026ae99d..be2916c1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -101,6 +101,10 @@ AC_ARG_ENABLE(power-altivec,
   AC_HELP_STRING([--enable-power-altivec], [Enable POWER altivec and vsx extensions. (default=no)]),,
   [enable_altivec=no])
 
+AC_ARG_ENABLE(s390x-msa-x1,
+  AC_HELP_STRING([--enable-s390x-msa-x1], [Enable message-security assist extension 1 on z/Architecture. (default=no)]),,
+  [enable_s390x_msa_x1=no])
+
 AC_ARG_ENABLE(mini-gmp,
   AC_HELP_STRING([--enable-mini-gmp], [Enable mini-gmp, used instead of libgmp.]),,
   [enable_mini_gmp=no])
@@ -359,6 +363,17 @@ case "$host_cpu" in
       ABI=64
     ])
     ;;
+  *s390x*)
+    AC_TRY_COMPILE([
+#if defined(__s390x__)
+#error 64-bit s390x
+#endif
+    ], [], [
+      ABI=32
+    ], [
+      ABI=64
+    ])
+    ;;
 esac
 
 if test "x$ABI" != xstandard ; then
@@ -512,7 +527,14 @@ if test "x$enable_assembler" = xyes ; then
 	fi
       fi
       ;;
-
+    *s390x*)
+      if test "$ABI" = 64 ; then
+	asm_path="s390x"
+        if test "$enable_s390x_msa_x1" = yes ; then
+          asm_path="s390x/msa_x1 $asm_path"
+	fi
+      fi
+      ;;
     *)
       enable_assembler=no
       ;;
diff --git a/s390x/README b/s390x/README
new file mode 100644
index 00000000..249a1c08
--- /dev/null
+++ b/s390x/README
@@ -0,0 +1,60 @@
+Registers Conventions[1]
+
+Register Status Use
+
+r0, r1     General purpose                                       Volatile
+r2         Parameter passing and return values                   Volatile
+r3, r4, r5 Parameter passing                                     Volatile
+r6         Parameter passing                                     Saved
+r7 - r11   Local variables                                       Saved
+r12        Local variable, commonly used as GOT pointer          Saved
+r13        Local variable, commonly used as Literal Pool pointer Saved
+r14        Return address                                        Volatile
+r15        Stack pointer                                         Saved
+
+f0, f2, f4, f6 Parameter passing and return values Volatile
+f1, f3, f5, f7 General purpose                     Volatile
+f8 – f15       General purpose                     Saved
+
+Vector Register Conventions
+
+Register Use
+
+VR0 - VR7    Volatile
+VR8 - VR15   Bytes 0-7 are non-volatile, Bytes 8-15 are volatile
+VR16 - VR23  Non-volatile
+VR24 - VR31  Volatile
+
+General Registers[2]
+
+In addition to their use as accumulators in general
+arithmetic and logical operations, 15 of the 16 general
+registers are also used as base-address and
+index registers in address generation. In these
+cases, the registers are designated by a four-bit B
+field or X field in an instruction. A value of zero in the
+B or X field specifies that no base or index is to be
+applied, and, thus, general register 0 cannot be designated
+as containing a base address or index.
+
+Parameter passing[1]
+
+Values shorter than 64 bits are sign- or zero-extended (as appropriate)
+to 64 bits. Arguments not handled in the registers are passed in the parameter
+words of the caller’s stack frame.
+
+Dynamic stack space allocation[1]
+
+1. After a new stack frame is acquired, and before the first dynamic space
+allocation, a new register, the frame pointer or FP, is set to the value of the
+stack pointer.
+2. The amount of dynamic space to be allocated is rounded up to a multiple of 8
+bytes, so that 8-byte stack alignment is maintained.
+3. The stack pointer is decreased by the rounded byte count, and the address of
+the previous stack frame (the back chain) may be stored at the word addressed
+by the new stack pointer. The back chain is not necessary to restore from this
+allocation at the end of the function since the frame pointer can be used to
+restore the stack pointer.
+
+[1] http://legacy.redhat.com/pub/redhat/linux/7.1/es/os/s390x/doc/lzsabi0.pdf
+[2] https://www.ibm.com/support/pages/zarchitecture-principles-operation