407 lines
13 KiB
C
407 lines
13 KiB
C
/***************************************************************************/
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/* */
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/* ftcalc.h */
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/* */
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/* Arithmetic computations (specification). */
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/* */
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/* Copyright 1996-2006, 2008, 2009, 2012-2014 by */
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/* David Turner, Robert Wilhelm, and Werner Lemberg. */
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/* */
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/* This file is part of the FreeType project, and may only be used, */
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/* modified, and distributed under the terms of the FreeType project */
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/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
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/* this file you indicate that you have read the license and */
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/* understand and accept it fully. */
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/* */
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/***************************************************************************/
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#ifndef __FTCALC_H__
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#define __FTCALC_H__
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#include <ft2build.h>
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#include FT_FREETYPE_H
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FT_BEGIN_HEADER
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/*************************************************************************/
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/* */
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/* FT_MulDiv() and FT_MulFix() are declared in freetype.h. */
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/* */
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/*************************************************************************/
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#ifndef FT_CONFIG_OPTION_NO_ASSEMBLER
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/* Provide assembler fragments for performance-critical functions. */
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/* These must be defined `static __inline__' with GCC. */
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#if defined( __CC_ARM ) || defined( __ARMCC__ ) /* RVCT */
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#define FT_MULFIX_ASSEMBLER FT_MulFix_arm
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/* documentation is in freetype.h */
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static __inline FT_Int32
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FT_MulFix_arm( FT_Int32 a,
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FT_Int32 b )
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{
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register FT_Int32 t, t2;
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__asm
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{
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smull t2, t, b, a /* (lo=t2,hi=t) = a*b */
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mov a, t, asr #31 /* a = (hi >> 31) */
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add a, a, #0x8000 /* a += 0x8000 */
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adds t2, t2, a /* t2 += a */
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adc t, t, #0 /* t += carry */
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mov a, t2, lsr #16 /* a = t2 >> 16 */
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orr a, a, t, lsl #16 /* a |= t << 16 */
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}
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return a;
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}
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#endif /* __CC_ARM || __ARMCC__ */
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#ifdef __GNUC__
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#if defined( __arm__ ) && \
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( !defined( __thumb__ ) || defined( __thumb2__ ) ) && \
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!( defined( __CC_ARM ) || defined( __ARMCC__ ) )
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#define FT_MULFIX_ASSEMBLER FT_MulFix_arm
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/* documentation is in freetype.h */
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static __inline__ FT_Int32
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FT_MulFix_arm( FT_Int32 a,
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FT_Int32 b )
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{
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register FT_Int32 t, t2;
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__asm__ __volatile__ (
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"smull %1, %2, %4, %3\n\t" /* (lo=%1,hi=%2) = a*b */
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"mov %0, %2, asr #31\n\t" /* %0 = (hi >> 31) */
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#if defined( __clang__ ) && defined( __thumb2__ )
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"add.w %0, %0, #0x8000\n\t" /* %0 += 0x8000 */
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#else
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"add %0, %0, #0x8000\n\t" /* %0 += 0x8000 */
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#endif
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"adds %1, %1, %0\n\t" /* %1 += %0 */
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"adc %2, %2, #0\n\t" /* %2 += carry */
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"mov %0, %1, lsr #16\n\t" /* %0 = %1 >> 16 */
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"orr %0, %0, %2, lsl #16\n\t" /* %0 |= %2 << 16 */
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: "=r"(a), "=&r"(t2), "=&r"(t)
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: "r"(a), "r"(b)
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: "cc" );
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return a;
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}
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#endif /* __arm__ && */
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/* ( __thumb2__ || !__thumb__ ) && */
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/* !( __CC_ARM || __ARMCC__ ) */
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#if defined( __i386__ )
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#define FT_MULFIX_ASSEMBLER FT_MulFix_i386
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/* documentation is in freetype.h */
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static __inline__ FT_Int32
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FT_MulFix_i386( FT_Int32 a,
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FT_Int32 b )
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{
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register FT_Int32 result;
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__asm__ __volatile__ (
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"imul %%edx\n"
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"movl %%edx, %%ecx\n"
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"sarl $31, %%ecx\n"
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"addl $0x8000, %%ecx\n"
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"addl %%ecx, %%eax\n"
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"adcl $0, %%edx\n"
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"shrl $16, %%eax\n"
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"shll $16, %%edx\n"
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"addl %%edx, %%eax\n"
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: "=a"(result), "=d"(b)
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: "a"(a), "d"(b)
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: "%ecx", "cc" );
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return result;
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}
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#endif /* i386 */
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#endif /* __GNUC__ */
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#ifdef _MSC_VER /* Visual C++ */
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#ifdef _M_IX86
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#define FT_MULFIX_ASSEMBLER FT_MulFix_i386
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/* documentation is in freetype.h */
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static __inline FT_Int32
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FT_MulFix_i386( FT_Int32 a,
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FT_Int32 b )
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{
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register FT_Int32 result;
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__asm
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{
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mov eax, a
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mov edx, b
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imul edx
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mov ecx, edx
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sar ecx, 31
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add ecx, 8000h
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add eax, ecx
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adc edx, 0
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shr eax, 16
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shl edx, 16
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add eax, edx
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mov result, eax
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}
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return result;
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}
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#endif /* _M_IX86 */
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#endif /* _MSC_VER */
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#if defined( __GNUC__ ) && defined( __x86_64__ )
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#define FT_MULFIX_ASSEMBLER FT_MulFix_x86_64
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static __inline__ FT_Int32
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FT_MulFix_x86_64( FT_Int32 a,
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FT_Int32 b )
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{
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/* Temporarily disable the warning that C90 doesn't support */
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/* `long long'. */
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#if __GNUC__ > 4 || ( __GNUC__ == 4 && __GNUC_MINOR__ >= 6 )
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wlong-long"
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#endif
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#if 1
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/* Technically not an assembly fragment, but GCC does a really good */
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/* job at inlining it and generating good machine code for it. */
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long long ret, tmp;
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ret = (long long)a * b;
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tmp = ret >> 63;
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ret += 0x8000 + tmp;
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return (FT_Int32)( ret >> 16 );
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#else
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/* For some reason, GCC 4.6 on Ubuntu 12.04 generates invalid machine */
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/* code from the lines below. The main issue is that `wide_a' is not */
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/* properly initialized by sign-extending `a'. Instead, the generated */
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/* machine code assumes that the register that contains `a' on input */
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/* can be used directly as a 64-bit value, which is wrong most of the */
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/* time. */
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long long wide_a = (long long)a;
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long long wide_b = (long long)b;
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long long result;
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__asm__ __volatile__ (
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"imul %2, %1\n"
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"mov %1, %0\n"
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"sar $63, %0\n"
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"lea 0x8000(%1, %0), %0\n"
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"sar $16, %0\n"
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: "=&r"(result), "=&r"(wide_a)
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: "r"(wide_b)
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: "cc" );
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return (FT_Int32)result;
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#endif
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#if __GNUC__ > 4 || ( __GNUC__ == 4 && __GNUC_MINOR__ >= 6 )
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#pragma GCC diagnostic pop
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#endif
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}
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#endif /* __GNUC__ && __x86_64__ */
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#endif /* !FT_CONFIG_OPTION_NO_ASSEMBLER */
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#ifdef FT_CONFIG_OPTION_INLINE_MULFIX
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#ifdef FT_MULFIX_ASSEMBLER
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#define FT_MulFix( a, b ) FT_MULFIX_ASSEMBLER( (FT_Int32)(a), (FT_Int32)(b) )
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#endif
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#endif
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_MulDiv_No_Round */
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/* */
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/* <Description> */
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/* A very simple function used to perform the computation `(a*b)/c' */
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/* (without rounding) with maximum accuracy (it uses a 64-bit */
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/* intermediate integer whenever necessary). */
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/* */
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/* This function isn't necessarily as fast as some processor specific */
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/* operations, but is at least completely portable. */
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/* */
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/* <Input> */
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/* a :: The first multiplier. */
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/* b :: The second multiplier. */
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/* c :: The divisor. */
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/* */
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/* <Return> */
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/* The result of `(a*b)/c'. This function never traps when trying to */
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/* divide by zero; it simply returns `MaxInt' or `MinInt' depending */
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/* on the signs of `a' and `b'. */
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/* */
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FT_BASE( FT_Long )
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FT_MulDiv_No_Round( FT_Long a,
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FT_Long b,
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FT_Long c );
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/*
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* A variant of FT_Matrix_Multiply which scales its result afterwards.
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* The idea is that both `a' and `b' are scaled by factors of 10 so that
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* the values are as precise as possible to get a correct result during
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* the 64bit multiplication. Let `sa' and `sb' be the scaling factors of
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* `a' and `b', respectively, then the scaling factor of the result is
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* `sa*sb'.
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*/
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FT_BASE( void )
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FT_Matrix_Multiply_Scaled( const FT_Matrix* a,
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FT_Matrix *b,
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FT_Long scaling );
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/*
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* A variant of FT_Vector_Transform. See comments for
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* FT_Matrix_Multiply_Scaled.
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*/
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FT_BASE( void )
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FT_Vector_Transform_Scaled( FT_Vector* vector,
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const FT_Matrix* matrix,
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FT_Long scaling );
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/*
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* Return -1, 0, or +1, depending on the orientation of a given corner.
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* We use the Cartesian coordinate system, with positive vertical values
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* going upwards. The function returns +1 if the corner turns to the
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* left, -1 to the right, and 0 for undecidable cases.
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*/
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FT_BASE( FT_Int )
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ft_corner_orientation( FT_Pos in_x,
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FT_Pos in_y,
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FT_Pos out_x,
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FT_Pos out_y );
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/*
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* Return TRUE if a corner is flat or nearly flat. This is equivalent to
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* saying that the corner point is close to its neighbors, or inside an
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* ellipse defined by the neighbor focal points to be more precise.
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*/
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FT_BASE( FT_Int )
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ft_corner_is_flat( FT_Pos in_x,
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FT_Pos in_y,
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FT_Pos out_x,
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FT_Pos out_y );
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/*
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* Return the most significant bit index.
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*/
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#ifndef FT_CONFIG_OPTION_NO_ASSEMBLER
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#if defined( __GNUC__ ) && \
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( __GNUC__ > 3 || ( __GNUC__ == 3 && __GNUC_MINOR__ >= 4 ) )
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#if FT_SIZEOF_INT == 4
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#define FT_MSB( x ) ( 31 - __builtin_clz( x ) )
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#elif FT_SIZEOF_LONG == 4
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#define FT_MSB( x ) ( 31 - __builtin_clzl( x ) )
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#endif
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#endif /* __GNUC__ */
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#endif /* !FT_CONFIG_OPTION_NO_ASSEMBLER */
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#ifndef FT_MSB
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FT_BASE( FT_Int )
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FT_MSB( FT_UInt32 z );
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#endif
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/*
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* Return sqrt(x*x+y*y), which is the same as `FT_Vector_Length' but uses
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* two fixed-point arguments instead.
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*/
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FT_BASE( FT_Fixed )
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FT_Hypot( FT_Fixed x,
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FT_Fixed y );
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#if 0
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/*************************************************************************/
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/* */
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/* <Function> */
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/* FT_SqrtFixed */
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/* */
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/* <Description> */
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/* Computes the square root of a 16.16 fixed-point value. */
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/* */
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/* <Input> */
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/* x :: The value to compute the root for. */
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/* */
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/* <Return> */
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/* The result of `sqrt(x)'. */
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/* */
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/* <Note> */
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/* This function is not very fast. */
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/* */
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FT_BASE( FT_Int32 )
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FT_SqrtFixed( FT_Int32 x );
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#endif /* 0 */
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#define INT_TO_F26DOT6( x ) ( (FT_Long)(x) << 6 )
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#define INT_TO_F2DOT14( x ) ( (FT_Long)(x) << 14 )
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#define INT_TO_FIXED( x ) ( (FT_Long)(x) << 16 )
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#define F2DOT14_TO_FIXED( x ) ( (FT_Long)(x) << 2 )
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#define FLOAT_TO_FIXED( x ) ( (FT_Long)( x * 65536.0 ) )
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#define FIXED_TO_INT( x ) ( FT_RoundFix( x ) >> 16 )
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#define ROUND_F26DOT6( x ) ( x >= 0 ? ( ( (x) + 32 ) & -64 ) \
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: ( -( ( 32 - (x) ) & -64 ) ) )
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FT_END_HEADER
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#endif /* __FTCALC_H__ */
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/* END */
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