libavcodec/arm/vp56_arith.h
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00001 /*
00002  * Copyright (C) 2010 Mans Rullgard <mans@mansr.com>
00003  *
00004  * This file is part of FFmpeg.
00005  *
00006  * FFmpeg is free software; you can redistribute it and/or
00007  * modify it under the terms of the GNU Lesser General Public
00008  * License as published by the Free Software Foundation; either
00009  * version 2.1 of the License, or (at your option) any later version.
00010  *
00011  * FFmpeg is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014  * Lesser General Public License for more details.
00015  *
00016  * You should have received a copy of the GNU Lesser General Public
00017  * License along with FFmpeg; if not, write to the Free Software
00018  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00019  */
00020 
00021 #ifndef AVCODEC_ARM_VP56_ARITH_H
00022 #define AVCODEC_ARM_VP56_ARITH_H
00023 
00024 #if CONFIG_THUMB
00025 #   define A(x)
00026 #   define T(x) x
00027 #else
00028 #   define A(x) x
00029 #   define T(x)
00030 #endif
00031 
00032 #if HAVE_ARMV6 && HAVE_INLINE_ASM
00033 
00034 #define vp56_rac_get_prob vp56_rac_get_prob_armv6
00035 static inline int vp56_rac_get_prob_armv6(VP56RangeCoder *c, int pr)
00036 {
00037     unsigned shift     = ff_vp56_norm_shift[c->high];
00038     unsigned code_word = c->code_word << shift;
00039     unsigned high      = c->high << shift;
00040     unsigned bit;
00041 
00042     __asm__ ("adds    %3,  %3,  %0           \n"
00043              "itt     cs                     \n"
00044              "cmpcs   %7,  %4                \n"
00045            A("ldrcsh  %2,  [%4], #2          \n")
00046            T("ldrhcs  %2,  [%4], #2          \n")
00047              "rsb     %0,  %6,  #256         \n"
00048              "smlabb  %0,  %5,  %6,  %0      \n"
00049            T("itttt   cs                     \n")
00050              "rev16cs %2,  %2                \n"
00051            T("lslcs   %2,  %2,  %3           \n")
00052            T("orrcs   %1,  %1,  %2           \n")
00053            A("orrcs   %1,  %1,  %2,  lsl %3  \n")
00054              "subcs   %3,  %3,  #16          \n"
00055              "lsr     %0,  %0,  #8           \n"
00056              "cmp     %1,  %0,  lsl #16      \n"
00057              "ittte   ge                     \n"
00058              "subge   %1,  %1,  %0,  lsl #16 \n"
00059              "subge   %0,  %5,  %0           \n"
00060              "movge   %2,  #1                \n"
00061              "movlt   %2,  #0                \n"
00062              : "=&r"(c->high), "=&r"(c->code_word), "=&r"(bit),
00063                "+&r"(c->bits), "+&r"(c->buffer)
00064              : "r"(high), "r"(pr), "r"(c->end - 1),
00065                "0"(shift), "1"(code_word)
00066              : "cc");
00067 
00068     return bit;
00069 }
00070 
00071 #define vp56_rac_get_prob_branchy vp56_rac_get_prob_branchy_armv6
00072 static inline int vp56_rac_get_prob_branchy_armv6(VP56RangeCoder *c, int pr)
00073 {
00074     unsigned shift     = ff_vp56_norm_shift[c->high];
00075     unsigned code_word = c->code_word << shift;
00076     unsigned high      = c->high << shift;
00077     unsigned low;
00078     unsigned tmp;
00079 
00080     __asm__ ("adds    %3,  %3,  %0           \n"
00081              "itt     cs                     \n"
00082              "cmpcs   %7,  %4                \n"
00083            A("ldrcsh  %2,  [%4], #2          \n")
00084            T("ldrhcs  %2,  [%4], #2          \n")
00085              "rsb     %0,  %6,  #256         \n"
00086              "smlabb  %0,  %5,  %6,  %0      \n"
00087            T("itttt   cs                     \n")
00088              "rev16cs %2,  %2                \n"
00089            T("lslcs   %2,  %2,  %3           \n")
00090            T("orrcs   %1,  %1,  %2           \n")
00091            A("orrcs   %1,  %1,  %2,  lsl %3  \n")
00092              "subcs   %3,  %3,  #16          \n"
00093              "lsr     %0,  %0,  #8           \n"
00094              "lsl     %2,  %0,  #16          \n"
00095              : "=&r"(low), "+&r"(code_word), "=&r"(tmp),
00096                "+&r"(c->bits), "+&r"(c->buffer)
00097              : "r"(high), "r"(pr), "r"(c->end - 1), "0"(shift)
00098              : "cc");
00099 
00100     if (code_word >= tmp) {
00101         c->high      = high - low;
00102         c->code_word = code_word - tmp;
00103         return 1;
00104     }
00105 
00106     c->high      = low;
00107     c->code_word = code_word;
00108     return 0;
00109 }
00110 
00111 #endif
00112 
00113 #endif /* AVCODEC_ARM_VP56_ARITH_H */