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FFmpeg/libavcodec/arm/vp56_arith.h
Mans Rullgard 9829a81bcd ARM: vp56: allow inline asm to build with clang
The clang integrated assembler does not support pre-UAL syntax,
while gcc requires pre-UAL syntax for ARM code.  A patch[1] for
clang to support the old syntax as well has been ignored since
January.

This patch chooses the syntax appropriate for each compiler,
allowing both to build the code.  Notably, this change allows
building for iphone with the latest Apple Xcode update.

[1] http://llvm.org/bugs/show_bug.cgi?id=11855

Signed-off-by: Mans Rullgard <mans@mansr.com>
2012-08-04 00:59:14 +01:00

122 lines
4.1 KiB
C

/*
* Copyright (C) 2010 Mans Rullgard <mans@mansr.com>
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_ARM_VP56_ARITH_H
#define AVCODEC_ARM_VP56_ARITH_H
#if CONFIG_THUMB
# define A(x)
# define T(x) x
#else
# define A(x) x
# define T(x)
#endif
#if CONFIG_THUMB || defined __clang__
# define L(x)
# define U(x) x
#else
# define L(x) x
# define U(x)
#endif
#if HAVE_ARMV6 && HAVE_INLINE_ASM
#define vp56_rac_get_prob vp56_rac_get_prob_armv6
static inline int vp56_rac_get_prob_armv6(VP56RangeCoder *c, int pr)
{
unsigned shift = ff_vp56_norm_shift[c->high];
unsigned code_word = c->code_word << shift;
unsigned high = c->high << shift;
unsigned bit;
__asm__ ("adds %3, %3, %0 \n"
"itt cs \n"
"cmpcs %7, %4 \n"
L("ldrcsh %2, [%4], #2 \n")
U("ldrhcs %2, [%4], #2 \n")
"rsb %0, %6, #256 \n"
"smlabb %0, %5, %6, %0 \n"
T("itttt cs \n")
"rev16cs %2, %2 \n"
T("lslcs %2, %2, %3 \n")
T("orrcs %1, %1, %2 \n")
A("orrcs %1, %1, %2, lsl %3 \n")
"subcs %3, %3, #16 \n"
"lsr %0, %0, #8 \n"
"cmp %1, %0, lsl #16 \n"
"ittte ge \n"
"subge %1, %1, %0, lsl #16 \n"
"subge %0, %5, %0 \n"
"movge %2, #1 \n"
"movlt %2, #0 \n"
: "=&r"(c->high), "=&r"(c->code_word), "=&r"(bit),
"+&r"(c->bits), "+&r"(c->buffer)
: "r"(high), "r"(pr), "r"(c->end - 1),
"0"(shift), "1"(code_word)
: "cc");
return bit;
}
#define vp56_rac_get_prob_branchy vp56_rac_get_prob_branchy_armv6
static inline int vp56_rac_get_prob_branchy_armv6(VP56RangeCoder *c, int pr)
{
unsigned shift = ff_vp56_norm_shift[c->high];
unsigned code_word = c->code_word << shift;
unsigned high = c->high << shift;
unsigned low;
unsigned tmp;
__asm__ ("adds %3, %3, %0 \n"
"itt cs \n"
"cmpcs %7, %4 \n"
L("ldrcsh %2, [%4], #2 \n")
U("ldrhcs %2, [%4], #2 \n")
"rsb %0, %6, #256 \n"
"smlabb %0, %5, %6, %0 \n"
T("itttt cs \n")
"rev16cs %2, %2 \n"
T("lslcs %2, %2, %3 \n")
T("orrcs %1, %1, %2 \n")
A("orrcs %1, %1, %2, lsl %3 \n")
"subcs %3, %3, #16 \n"
"lsr %0, %0, #8 \n"
"lsl %2, %0, #16 \n"
: "=&r"(low), "+&r"(code_word), "=&r"(tmp),
"+&r"(c->bits), "+&r"(c->buffer)
: "r"(high), "r"(pr), "r"(c->end - 1), "0"(shift)
: "cc");
if (code_word >= tmp) {
c->high = high - low;
c->code_word = code_word - tmp;
return 1;
}
c->high = low;
c->code_word = code_word;
return 0;
}
#endif
#endif /* AVCODEC_ARM_VP56_ARITH_H */