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Add assembler code for TT_MulFix14 and TT_DotFix14.

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This patch provides slightly optimized versions for ARM, x86, and
x86_64 CPUs if built with GCC.

Also remove some dead code.

* src/truetype/ttinterp.c (TT_MulFix14_arm, TT_MulFix14_long_long,
TT_DotFix14_long_long): New functions.
This commit is contained in:
David Turner 2013-07-16 13:18:00 +02:00 committed by Werner Lemberg
parent b28908860d
commit f66d48e923
2 changed files with 136 additions and 24 deletions
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12
ChangeLog
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@ -1,3 +1,15 @@
2013-07-16 David Turner <digit@google.com>
[truetype] Add assembler code for TT_MulFix14 and TT_DotFix14.
This patch provides slightly optimized versions for ARM, x86, and
x86_64 CPUs if built with GCC.
Also remove some dead code.
* src/truetype/ttinterp.c (TT_MulFix14_arm, TT_MulFix14_long_long,
TT_DotFix14_long_long): New functions.
2013-07-16 David Turner <digit@google.com>
Optimize FT_MulFix for x86_64 GCC builds.

148
src/truetype/ttinterp.c
View File

@ -1437,8 +1437,99 @@
#undef PACK
#if 1
#ifndef FT_CONFIG_OPTION_NO_ASSEMBLER
#if defined( __arm__ ) && \
( defined( __thumb2__ ) || !defined( __thumb__ ) )
#define TT_MulFix14 TT_MulFix14_arm
static FT_Int32
TT_MulFix14_arm( FT_Int32 a,
FT_Int b )
{
register FT_Int32 t, t2;
#if defined( __CC_ARM ) || defined( __ARMCC__ )
__asm
{
smull t2, t, b, a /* (lo=t2,hi=t) = a*b */
mov a, t, asr #31 /* a = (hi >> 31) */
add a, a, #0x2000 /* a += 0x2000 */
adds t2, t2, a /* t2 += a */
adc t, t, #0 /* t += carry */
mov a, t2, lsr #14 /* a = t2 >> 14 */
orr a, a, t, lsl #18 /* a |= t << 18 */
}
#elif defined( __GNUC__ )
__asm__ __volatile__ (
"smull %1, %2, %4, %3\n\t" /* (lo=%1,hi=%2) = a*b */
"mov %0, %2, asr #31\n\t" /* %0 = (hi >> 31) */
"add %0, %0, #0x2000\n\t" /* %0 += 0x2000 */
"adds %1, %1, %0\n\t" /* %1 += %0 */
"adc %2, %2, #0\n\t" /* %2 += carry */
"mov %0, %1, lsr #14\n\t" /* %0 = %1 >> 16 */
"orr %0, %0, %2, lsl #18\n\t" /* %0 |= %2 << 16 */
: "=r"(a), "=&r"(t2), "=&r"(t)
: "r"(a), "r"(b)
: "cc" );
#endif
return a;
}
#endif /* __arm__ && ( __thumb2__ || !__thumb__ ) */
#endif /* !FT_CONFIG_OPTION_NO_ASSEMBLER */
#if defined( __GNUC__ ) && \
( defined( __i386__ ) || defined( __x86_64__ ) )
#define TT_MulFix14 TT_MulFix14_long_long
/* This is declared `noinline' because inlining the function results */
/* in slower code. The `pure' attribute indicates that the result */
/* only depends on the parameters. */
static __attribute__(( noinline ))
__attribute__(( pure )) FT_Int32
TT_MulFix14_long_long( FT_Int32 a,
FT_Int b )
{
/* Temporarily disable the warning that C90 doesn't support */
/* `long long'. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wlong-long"
long long ret = (long long)a * b;
/* The following line assumes that right shifting of signed values */
/* will actually preserve the sign bit. The exact behaviour is */
/* undefined, but this is true on x86 and x86_64. */
long long tmp = ret >> 63;
ret += 0x2000 + tmp;
return (FT_Int32)( ret >> 14 );
#pragma GCC diagnostic pop
}
#endif /* __GNUC__ && ( __i386__ || __x86_64__ ) */
#ifndef TT_MulFix14
/* Compute (a*b)/2^14 with maximum accuracy and rounding. */
/* This is optimized to be faster than calling FT_MulFix() */
/* for platforms where sizeof(int) == 2. */
static FT_Int32
TT_MulFix14( FT_Int32 a,
FT_Int b )
@ -1470,37 +1561,44 @@
return sign >= 0 ? (FT_Int32)mid : -(FT_Int32)mid;
}
#else
#endif /* !TT_MulFix14 */
/* compute (a*b)/2^14 with maximum accuracy and rounding */
static FT_Int32
TT_MulFix14( FT_Int32 a,
FT_Int b )
#if defined( __GNUC__ ) && \
( defined( __i386__ ) || \
defined( __x86_64__ ) || \
defined( __arm__ ) )
#define TT_DotFix14 TT_DotFix14_long_long
static __attribute__(( pure )) FT_Int32
TT_DotFix14_long_long( FT_Int32 ax,
FT_Int32 ay,
FT_Int bx,
FT_Int by )
{
FT_Int32 m, s, hi;
FT_UInt32 l, lo;
/* Temporarily disable the warning that C90 doesn't support */
/* `long long'. */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wlong-long"
long long temp1 = (long long)ax * bx;
long long temp2 = (long long)ay * by;
/* compute ax*bx as 64-bit value */
l = (FT_UInt32)( ( a & 0xFFFFU ) * b );
m = ( a >> 16 ) * b;
temp1 += temp2;
temp2 = temp1 >> 63;
temp1 += 0x2000 + temp2;
lo = l + ( (FT_UInt32)m << 16 );
hi = ( m >> 16 ) + ( (FT_Int32)l >> 31 ) + ( lo < l );
return (FT_Int32)( temp1 >> 14 );
/* divide the result by 2^14 with rounding */
s = hi >> 31;
l = lo + (FT_UInt32)s;
hi += s + ( l < lo );
lo = l;
l = lo + 0x2000U;
hi += l < lo;
return (FT_Int32)( ( (FT_UInt32)hi << 18 ) | ( l >> 14 ) );
#pragma GCC diagnostic pop
}
#endif
#endif /* __GNUC__ && (__arm__ || __i386__ || __x86_64__) */
#ifndef TT_DotFix14
/* compute (ax*bx+ay*by)/2^14 with maximum accuracy and rounding */
static FT_Int32
@ -1543,6 +1641,8 @@
return (FT_Int32)( ( (FT_UInt32)hi << 18 ) | ( l >> 14 ) );
}
#endif /* TT_DotFix14 */
/*************************************************************************/
/* */