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[base] Update FT_MulFix inlining.
Resolves inconsistencies in 64-bit multiplication discussed in !355. Importantly, FT_MulFix arguments and return value is FT_Long, whatever sizeof FT_Long is on 64-bit platforms: 8 bytes on Linux or 4 bytes on Windows. * include/freetype/internal/ftcalc.h (FT_MulFix_x86_64): Removed. (FT_MulFix_64): Generalize and prioritize the inline implementation for all 64-bit platforms ifdef FT_INT64. * src/base/ftcalc.c (FT_MulFix)[FT_INT64]: Call 'FT_MulFix_64'. * src/base/ftbase.c: Include 'ftcalc.c' after the FT_MulFix callers to enable its inlining.
This commit is contained in:
Alexei Podtelezhnikov
parent
fc67794e15
commit
8f67545d72
3 changed files with 30 additions and 75 deletions
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@ -33,9 +33,27 @@ FT_BEGIN_HEADER
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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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#ifdef FT_CONFIG_OPTION_INLINE_MULFIX
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#ifdef FT_INT64
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static inline FT_Long
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FT_MulFix_64( FT_Long a,
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FT_Long b )
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{
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FT_Int64 ab = (FT_Int64)a * b;
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ab += 0x8000 + ( ab >> 63 ); /* rounding phase */
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return (FT_Long)( ab >> 16 );
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}
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#define FT_MulFix( a, b ) FT_MulFix_64( a, b )
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#elif !defined( FT_CONFIG_OPTION_NO_ASSEMBLER )
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/* Provide 32-bit assembler fragments for optimized FT_MulFix. */
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/* These must be defined `static __inline__' or similar. */
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#if defined( __CC_ARM ) || defined( __ARMCC__ ) /* RVCT */
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@ -177,73 +195,11 @@ FT_BEGIN_HEADER
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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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#define FT_MulFix( a, b ) FT_MULFIX_ASSEMBLER( (FT_Int32)(a), (FT_Int32)(b) )
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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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#endif /* FT_CONFIG_OPTION_INLINE_MULFIX */
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/**************************************************************************
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@ -19,7 +19,6 @@
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#define FT_MAKE_OPTION_SINGLE_OBJECT
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#include "ftadvanc.c"
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#include "ftcalc.c"
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#include "ftcolor.c"
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#include "ftdbgmem.c"
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#include "fterrors.c"
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@ -35,6 +34,7 @@
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#include "ftsnames.c"
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#include "ftstream.c"
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#include "fttrigon.c"
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#include "ftcalc.c" /* included after FT_MulFix callers to inline it */
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#include "ftutil.c"
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@ -38,13 +38,12 @@
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#include <freetype/internal/ftdebug.h>
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#include <freetype/internal/ftobjs.h>
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#ifdef FT_MULFIX_ASSEMBLER
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/* cancel inlining macro from internal/ftcalc.h */
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#ifdef FT_MulFix
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#undef FT_MulFix
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#endif
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/* we need to emulate a 64-bit data type if a real one isn't available */
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/* we need to emulate a 64-bit data type if one isn't available */
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#ifndef FT_INT64
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typedef struct FT_Int64_
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@ -225,9 +224,9 @@
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FT_MulFix( FT_Long a_,
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FT_Long b_ )
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{
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#ifdef FT_MULFIX_ASSEMBLER
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#ifdef FT_CONFIG_OPTION_INLINE_MULFIX
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return FT_MULFIX_ASSEMBLER( (FT_Int32)a_, (FT_Int32)b_ );
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return FT_MulFix_64( a_, b_ );
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#else
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@ -236,7 +235,7 @@
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/* this requires arithmetic right shift of signed numbers */
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return (FT_Long)( ( ab + 0x8000L - ( ab < 0 ) ) >> 16 );
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#endif /* FT_MULFIX_ASSEMBLER */
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#endif /* FT_CONFIG_OPTION_INLINE_MULFIX */
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}
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