From 3737dd1cd31f72afa905c5efed7dc1d605813229 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=C3=A5ns=20Rullg=C3=A5rd?= <mans@mansr.com>
Date: Mon, 4 May 2009 17:31:15 +0000
Subject: [PATCH] PPC: implement MULH() in assembler

Left to its own devices, gcc calculates the full 64-bit product only to
discard the low 32 bits.  This forces it to do the right thing.

20% faster MP3 decoding on G4.

Originally committed as revision 18737 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/ppc/mathops.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libavcodec/ppc/mathops.h b/libavcodec/ppc/mathops.h
index adf04cb1da..2b5a5c4eb0 100644
--- a/libavcodec/ppc/mathops.h
+++ b/libavcodec/ppc/mathops.h
@@ -37,4 +37,11 @@
     __rt; })
 #endif
 
+#define MULH MULH
+static inline av_const int MULH(int a, int b){
+    int r;
+    __asm__ ("mulhw %0, %1, %2" : "=r"(r) : "r"(a), "r"(b));
+    return r;
+}
+
 #endif /* AVCODEC_PPC_MATHOPS_H */