SH4: add macros for setting and restoring FPSCR.PR bit

Originally committed as revision 15887 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/sh4/sh4.h

+/*
+ * Copyright (c) 2008 Mans Rullgard <mans@mansr.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_SH4_SH4_H
+#define AVCODEC_SH4_SH4_H
+
+#ifdef __SH4__
+#   define fp_single_enter(fpscr)                               \
+    do {                                                        \
+        __asm__ volatile ("sts   fpscr, %0     \n\t"            \
+                          "and   %1,    %0     \n\t"            \
+                          "lds   %0,    fpscr  \n\t"            \
+                          : "=&r"(fpscr) : "r"(~(1<<19)));      \
+    } while (0)
+
+#   define fp_single_leave(fpscr)                       \
+    do {                                                \
+        __asm__ volatile ("or    %1,    %0     \n\t"    \
+                          "lds   %0,    fpscr  \n\t"    \
+                          : "=&r"(fpscr) : "r"(1<<19)); \
+    } while (0)
+#else
+#   define fp_single_enter(fpscr) ((void)fpscr)
+#   define fp_single_leave(fpscr)
+#endif
+
+#endif /* AVCODEC_SH4_SH4_H */