[FFmpeg-cvslog] r25362 - in trunk: configure libavutil/x86_cpu.h

[ramiro]

Author: ramiro
Date: Wed Oct  6 03:26:13 2010
New Revision: 25362

Log:
Check whether compiler supports xmm registers in asm clobber list

Modified:
   trunk/configure
   trunk/libavutil/x86_cpu.h

Modified: trunk/configure
==============================================================================
--- trunk/configure	Wed Oct  6 00:06:18 2010	(r25361)
+++ trunk/configure	Wed Oct  6 03:26:13 2010	(r25362)
@@ -1074,6 +1074,7 @@ HAVE_LIST="
     VirtualAlloc
     winsock2_h
     xform_asm
+    xmm_clobbers
     yasm
 "
 
@@ -2585,6 +2586,9 @@ EOF
     check_asm ebx_available '""::"b"(0)' &&
         check_asm ebx_available '"":::"%ebx"'
 
+    # check whether xmm clobbers are supported
+    check_asm xmm_clobbers '"":::"%xmm0"'
+
     # check whether more than 10 operands are supported
     check_cc <<EOF && enable ten_operands
 int main(void) {

Modified: trunk/libavutil/x86_cpu.h
==============================================================================
--- trunk/libavutil/x86_cpu.h	Wed Oct  6 00:06:18 2010	(r25361)
+++ trunk/libavutil/x86_cpu.h	Wed Oct  6 03:26:13 2010	(r25362)
@@ -75,4 +75,24 @@ typedef int x86_reg;
 #    define BROKEN_RELOCATIONS 1
 #endif
 
+/*
+ * If gcc is not set to support sse (-msse) it will not accept xmm registers
+ * in the clobber list for inline asm. XMM_CLOBBERS takes a list of xmm
+ * registers to be marked as clobbered and evaluates to nothing if they are
+ * not supported, or to the list itself if they are supported. Since a clobber
+ * list may not be empty, XMM_CLOBBERS_ONLY should be used if the xmm
+ * registers are the only in the clobber list.
+ * For example a list with "eax" and "xmm0" as clobbers should become:
+ * : XMM_CLOBBERS("xmm0",) "eax"
+ * and a list with only "xmm0" should become:
+ * XMM_CLOBBERS_ONLY("xmm0")
+ */
+#if HAVE_XMM_CLOBBERS
+#    define XMM_CLOBBERS(...)        __VA_ARGS__
+#    define XMM_CLOBBERS_ONLY(...) : __VA_ARGS__
+#else
+#    define XMM_CLOBBERS(...)
+#    define XMM_CLOBBERS_ONLY(...)
+#endif
+
 #endif /* AVUTIL_X86_CPU_H */