filters_arm4.h

00001 /* Copyright (C) 2004 Jean-Marc Valin */
00002 /**
00003    @file filters_arm4.h
00004    @brief Various analysis/synthesis filters (ARM4 version)
00005 */
00006 /*
00007    Redistribution and use in source and binary forms, with or without
00008    modification, are permitted provided that the following conditions
00009    are met:
00010    
00011    - Redistributions of source code must retain the above copyright
00012    notice, this list of conditions and the following disclaimer.
00013    
00014    - Redistributions in binary form must reproduce the above copyright
00015    notice, this list of conditions and the following disclaimer in the
00016    documentation and/or other materials provided with the distribution.
00017    
00018    - Neither the name of the Xiph.org Foundation nor the names of its
00019    contributors may be used to endorse or promote products derived from
00020    this software without specific prior written permission.
00021    
00022    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00023    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00024    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
00025    A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
00026    CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
00027    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
00028    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
00029    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
00030    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
00031    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
00032    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00033 */
00034 
00035 #define OVERRIDE_NORMALIZE16
00036 int normalize16(const spx_sig_t *x, spx_word16_t *y, spx_sig_t max_scale, int len)
00037 {
00038    spx_sig_t max_val=1;
00039    int sig_shift;
00040    int dead1, dead2, dead3, dead4, dead5, dead6;
00041 
00042    __asm__ __volatile__ (
00043          "\tmov %1, #1 \n"
00044          "\tmov %3, #0 \n"
00045 
00046          ".normalize16loop1%=: \n"
00047 
00048          "\tldr %4, [%0], #4 \n"
00049          "\tcmps %4, %1 \n"
00050          "\tmovgt %1, %4 \n"
00051          "\tcmps %4, %3 \n"
00052          "\tmovlt %3, %4 \n"
00053 
00054          "\tsubs %2, %2, #1 \n"
00055          "\tbne .normalize16loop1%=\n"
00056 
00057          "\trsb %3, %3, #0 \n"
00058          "\tcmp %1, %3 \n"
00059          "\tmovlt %1, %3 \n"
00060    : "=r" (dead1), "=r" (max_val), "=r" (dead3), "=r" (dead4),
00061    "=r" (dead5), "=r" (dead6)
00062    : "0" (x), "2" (len)
00063    : "cc");
00064 
00065    sig_shift=0;
00066    while (max_val>max_scale)
00067    {
00068       sig_shift++;
00069       max_val >>= 1;
00070    }
00071    
00072    __asm__ __volatile__ (
00073          ".normalize16loop%=: \n"
00074 
00075          "\tldr %4, [%0], #4 \n"
00076          "\tldr %5, [%0], #4 \n"
00077          "\tmov %4, %4, asr %3 \n"
00078          "\tstrh %4, [%1], #2 \n"
00079          "\tldr %4, [%0], #4 \n"
00080          "\tmov %5, %5, asr %3 \n"
00081          "\tstrh %5, [%1], #2 \n"
00082          "\tldr %5, [%0], #4 \n"
00083          "\tmov %4, %4, asr %3 \n"
00084          "\tstrh %4, [%1], #2 \n"
00085          "\tsubs %2, %2, #1 \n"
00086          "\tmov %5, %5, asr %3 \n"
00087          "\tstrh %5, [%1], #2 \n"
00088 
00089          "\tbge .normalize16loop%=\n"
00090    : "=r" (dead1), "=r" (dead2), "=r" (dead3), "=r" (dead4),
00091    "=r" (dead5), "=r" (dead6)
00092    : "0" (x), "1" (y), "2" (len>>2), "3" (sig_shift)
00093    : "cc", "memory");
00094    return sig_shift;
00095 }
00096