x86cpuid.pl update [from HEAD].

diff --git a/crypto/x86cpuid.pl b/crypto/x86cpuid.pl
index 4a58651f0f9d4326971d7ffaf468786b2647c36a..d4066e8858270217b6e4f1969c14004d9f2d203c 100644 (file)
--- a/crypto/x86cpuid.pl
+++ b/crypto/x86cpuid.pl
@@ -153,6 +153,45 @@ for (@ARGV) { $sse2=1 if (/-DOPENSSL_IA32_SSE2/); }
        &ret    ();
 &function_end_B("OPENSSL_atomic_add");
 
+# This function can become handy under Win32 in situations when
+# we don't know which calling convention, __stdcall or __cdecl(*),
+# indirect callee is using. In C it can be deployed as
+#
+#ifdef OPENSSL_CPUID_OBJ
+#      type OPENSSL_indirect_call(void *f,...);
+#      ...
+#      OPENSSL_indirect_call(func,[up to $max arguments]);
+#endif
+#
+# (*)  it's designed to work even for __fastcall if number of
+#      arguments is 1 or 2!
+&function_begin_B("OPENSSL_indirect_call");
+       {
+       my $i,$max=7;           # $max has to be chosen as 4*n-1
+                               # in order to preserve eventual
+                               # stack alignment
+       &push   ("ebp");
+       &mov    ("ebp","esp");
+       &sub    ("esp",$max*4);
+       &mov    ("ecx",&DWP(12,"ebp"));
+       &mov    (&DWP(0,"esp"),"ecx");
+       &mov    ("edx",&DWP(16,"ebp"));
+       &mov    (&DWP(4,"esp"),"edx");
+       for($i=2;$i<$max;$i++)
+               {
+               # Some copies will be redundant/bogus...
+               &mov    ("eax",&DWP(12+$i*4,"ebp"));
+               &mov    (&DWP(0+$i*4,"esp"),"eax");
+               }
+       &call   (&DWP(8,"ebp"));# make the call...
+       &mov    ("esp","ebp");  # ... and just restore the stack pointer
+                               # without paying attention to what we called,
+                               # (__cdecl *func) or (__stdcall *one).
+       &pop    ("ebp");
+       &ret    ();
+       }
+&function_end_B("OPENSSL_indirect_call");
+
 &initseg("OPENSSL_cpuid_setup");
 
 &asm_finish();