[Spice-devel] [PATCHv2 05/12] common: don't duplicate find_msb implementation

[Christophe Fergeau]

---
 common/Makefile.am |    1 +
 common/bitops.h    |   89 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 common/gl_utils.h  |   58 ++--------------------------------
 common/quic.c      |   14 +-------
 4 files changed, 95 insertions(+), 67 deletions(-)
 create mode 100644 common/bitops.h

diff --git a/common/Makefile.am b/common/Makefile.am
index 501a6e1..dff9574 100644
--- a/common/Makefile.am
+++ b/common/Makefile.am
@@ -6,6 +6,7 @@ NULL =
 
 noinst_LTLIBRARIES = libspice-common.la
 libspice_common_la_SOURCES =		\
+	bitops.h			\
 	canvas_utils.c			\
 	canvas_utils.h			\
 	draw.h				\
diff --git a/common/bitops.h b/common/bitops.h
new file mode 100644
index 0000000..666d82d
--- /dev/null
+++ b/common/bitops.h
@@ -0,0 +1,89 @@
+/* -*- Mode: C; c-basic-offset: 4; indent-tabs-mode: nil -*- */
+/*
+   Copyright (C) 2009 Red Hat, Inc.
+
+   This library 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.
+
+   This library 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 this library; if not, write to the Free Software
+
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+*/
+
+#ifndef BITOPS_H
+#define BITOPS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef WIN32
+static inline int spice_bit_find_msb(uint32_t val)
+{
+    uint32_t r;
+    __asm {
+        bsr eax, val
+        jnz found
+        mov eax, -1
+
+found:
+        mov r, eax
+    }
+    return r + 1;
+}
+
+#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+static inline int spice_bit_find_msb(unsigned int val)
+{
+    int ret;
+
+    asm ("bsrl %1,%0\n\t"
+         "jnz 1f\n\t"
+         "movl $-1,%0\n"
+         "1:"
+         : "=r"(ret) : "r"(val));
+    return ret + 1;
+}
+
+#else
+static inline int spice_bit_find_msb(unsigned int val)
+{
+    signed char index = 31;
+
+    if(val == 0) {
+        return 0;
+    }
+
+    do {
+        if(val & 0x80000000) {
+            break;
+        }
+        val <<= 1;
+    } while(--index >= 0);
+
+    return index+1;
+}
+
+#endif
+
+static inline int spice_bit_next_pow2(unsigned int val)
+{
+    if ((val & (val - 1)) == 0) {
+        return val;
+    }
+    return 1 << spice_bit_find_msb(val);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/common/gl_utils.h b/common/gl_utils.h
index 175f131..c30be16 100644
--- a/common/gl_utils.h
+++ b/common/gl_utils.h
@@ -49,62 +49,10 @@ extern "C" {
 #define GLC_ERROR_TEST_FINISH ;
 #endif
 
-#ifdef WIN32
-static inline int find_msb(uint32_t val)
-{
-    uint32_t r;
-    __asm {
-        bsr eax, val
-        jnz found
-        mov eax, -1
+#include "bitops.h"
 
-found:
-        mov r, eax
-    }
-    return r + 1;
-}
-
-#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
-static inline int find_msb(unsigned int val)
-{
-    int ret;
-
-    asm ("bsrl %1,%0\n\t"
-         "jnz 1f\n\t"
-         "movl $-1,%0\n"
-         "1:"
-         : "=r"(ret) : "r"(val));
-    return ret + 1;
-}
-
-#else
-static inline int find_msb(unsigned int val)
-{
-    signed char index = 31;
-
-    if(val == 0) {
-        return 0;
-    }
-
-    do {
-        if(val & 0x80000000) {
-            break;
-        }
-        val <<= 1;
-    } while(--index >= 0);
-
-    return index+1;
-}
-
-#endif
-
-static inline int gl_get_to_power_two(unsigned int val)
-{
-    if ((val & (val - 1)) == 0) {
-        return val;
-    }
-    return 1 << find_msb(val);
-}
+#define find_msb spice_bit_find_msb
+#define gl_get_to_power_two spice_bit_next_pow2
 
 #ifdef __cplusplus
 }
diff --git a/common/quic.c b/common/quic.c
index 8f8d726..5a41399 100644
--- a/common/quic.c
+++ b/common/quic.c
@@ -25,6 +25,7 @@
 
 #include "quic.h"
 #include <spice/macros.h>
+#include "bitops.h"
 
 //#define DEBUG
 
@@ -707,17 +708,6 @@ static int decode_channel_run(Encoder *encoder, Channel *channel)
 
 #else
 
-static INLINE int find_msb(int x)
-{
-    int r;
-
-    __asm__("bsrl %1,%0\n\t"
-            "jnz 1f\n\t"
-            "movl $-1,%0\n"
-            "1:" : "=r" (r) : "rm" (x));
-    return r + 1;
-}
-
 static INLINE void encode_run(Encoder *encoder, unsigned int len)
 {
     int odd = len & 1U;
@@ -725,7 +715,7 @@ static INLINE void encode_run(Encoder *encoder, unsigned int len)
 
     len &= ~1U;
 
-    while ((msb = find_msb(len))) {
+    while ((msb = spice_bit_find_msb(len))) {
         len &= ~(1 << (msb - 1));
         ASSERT(encoder->usr, msb < 32);
         encode(encoder, (1 << (msb)) - 1, msb);
-- 
1.7.4.4