ref: 271106133a2e3e3e434f21fb81a3599381fd047f
parent: a8bcdf8ef6ecd1e6c8da655f9742f687e0892f49
author: David Turner <[email protected]>
date: Tue May 2 06:52:28 EDT 2000
added FT_Sqrt64 to ensure that all bytecode operations are strictly equivalent to the ones in FT 1.4 when compiling with the configuration macro FT_CONFIG_OPTION_OLD_CALCS defined..
--- a/src/base/ftcalc.c
+++ b/src/base/ftcalc.c
@@ -35,6 +35,25 @@
#include <ftobjs.h> /* for ABS() */
+#ifdef FT_CONFIG_OPTION_OLD_CALCS
+
+ static const FT_Long ft_square_roots[63] =
+ {+ 1, 1, 2, 3, 4, 5, 8, 11,
+ 16, 22, 32, 45, 64, 90, 128, 181,
+ 256, 362, 512, 724, 1024, 1448, 2048, 2896,
+ 4096, 5892, 8192, 11585, 16384, 23170, 32768, 46340,
+
+ 65536, 92681, 131072, 185363, 262144, 370727,
+ 524288, 741455, 1048576, 1482910, 2097152, 2965820,
+ 4194304, 5931641, 8388608, 11863283, 16777216, 23726566,
+
+ 33554432, 47453132, 67108864, 94906265,
+ 134217728, 189812531, 268435456, 379625062,
+ 536870912, 759250125, 1073741824, 1518500250,
+ 2147483647
+ };
+#else
/*************************************************************************/
/* */
/* <Function> */
@@ -50,7 +69,7 @@
/* <Return> */
/* The result of `sqrt(x)'. */
/* */
- BASE_FUNC
+ EXPORT_FUNC
FT_Int32 FT_Sqrt32( FT_Int32 x )
{FT_ULong val, root, newroot, mask;
@@ -76,8 +95,8 @@
return root;
}
+#endif /* OLD_CALCS */
-
#ifdef LONG64
@@ -211,6 +230,60 @@
}
+#ifdef FT_CONFIG_OPTION_OLD_CALCS
+ /*************************************************************************/
+ /* */
+ /* <Function> */
+ /* FT_Sqrt64 */
+ /* */
+ /* <Description> */
+ /* Computes the square root of a 64-bits value ! Yeah, that sounds */
+ /* stupid, but it's needed to obtain maximum accuracy in the */
+ /* TrueType bytecode interpreter.. */
+ /* */
+ /* <Input> */
+ /* l :: 64-bits integer */
+ /* */
+ /* <Return> */
+ /* The 32-bit square-root. */
+ /* */
+
+ static
+ int ft_order64( FT_Int64 z )
+ {+ int j = 0;
+
+ while ( z )
+ {+ z = (unsigned INT64)z >> 1;
+ j++;
+ }
+ return j - 1;
+ }
+
+
+ EXPORT_FUNC
+ FT_Int32 FT_Sqrt64( FT_Int64 l )
+ {+ FT_Int64 r, s;
+
+ if ( l <= 0 ) return 0;
+ if ( l == 1 ) return 1;
+
+ r = ft_square_roots[ft_order64( l )];
+
+ do
+ {+ s = r;
+ r = ( r + l/r ) >> 1;
+ }
+ while ( r > s || r*r > l );
+
+ return r;
+ }
+#endif
+
+
#else /* LONG64 */
@@ -437,7 +510,7 @@
/* <Note> */
/* Will be wrapped by the ADD_64() macro. */
/* */
- BASE_FUNC
+ EXPORT_FUNC
void FT_Add64( FT_Int64* x,
FT_Int64* y,
FT_Int64* z )
@@ -470,7 +543,7 @@
/* <Note> */
/* Will be wrapped by the MUL_64() macro. */
/* */
- BASE_FUNC
+ EXPORT_FUNC
void FT_MulTo64( FT_Int32 x,
FT_Int32 y,
FT_Int64* z )
@@ -536,7 +609,7 @@
/* <Note> */
/* Will be wrapped by the DIV_64() macro. */
/* */
- BASE_FUNC
+ EXPORT_FUNC
FT_Int32 FT_Div64by32( FT_Int64* x,
FT_Int32 y )
{@@ -584,6 +657,88 @@
return ( s < 0 ) ? -(FT_Int32)q : (FT_Int32)q;
}
+
+#ifdef FT_CONFIG_OPTION_OLD_CALCS
+
+ static
+ void FT_Sub64( FT_Int64* x, FT_Int64* y, FT_Int64* z )
+ {+ register FT_Word32 lo, hi;
+
+
+ lo = x->lo - y->lo;
+ hi = x->hi - y->hi - ( (FT_Int32)lo < 0 );
+
+ z->lo = lo;
+ z->hi = hi;
+ }
+
+ /*************************************************************************/
+ /* */
+ /* <Function> */
+ /* FT_Sqrt64 */
+ /* */
+ /* <Description> */
+ /* Computes the square root of a 64-bits value ! Yeah, that sounds */
+ /* stupid, but it's needed to obtain maximum accuracy in the */
+ /* TrueType bytecode interpreter.. */
+ /* */
+ /* <Input> */
+ /* z :: pointer to 64-bits integer */
+ /* */
+ /* <Return> */
+ /* The 32-bit square-root. */
+ /* */
+
+ static
+ int ft_order64( FT_Int64* z )
+ {+ FT_Word32 i;
+ int j;
+
+ i = z->lo;
+ j = 0;
+ if ( z->hi )
+ {+ i = z->hi;
+ j = 32;
+ }
+
+ while ( i > 0 )
+ {+ i >>= 1;
+ j++;
+ }
+ return j-1;
+ }
+
+ EXPORT_FUNC
+ FT_Int32 FT_Sqrt64( FT_Int64* l )
+ {+ FT_Int64 l2;
+ FT_Int32 r, s;
+
+
+ if ( (FT_Int32)l->hi < 0 ||
+ (l->hi == 0 && l->lo == 0) ) return 0;
+
+ s = ft_order64( l );
+ if ( s == 0 ) return 1;
+
+ r = ft_square_roots[s];
+ do
+ {+ s = r;
+ r = ( r + FT_Div64by32(l,r) ) >> 1;
+ FT_MulTo64( r, r, &l2 );
+ FT_Sub64 ( l, &l2, &l2 );
+ }
+ while ( r > s || (FT_Int32)l2.hi < 0 );
+
+ return r;
+ }
+
+#endif /* FT_CONFIG_OPTION_OLD_CALCS */
#endif /* LONG64 */
--- a/src/base/ftcalc.h
+++ b/src/base/ftcalc.h
@@ -37,6 +37,15 @@
#define DIV_64( x, y ) ( (x) / (y) )
+#ifdef FT_CONFIG_OPTION_OLD_CALCS
+
+#define SQRT_64( z ) FT_Sqrt64( z )
+
+ EXPORT_DEF
+ FT_Int32 FT_Sqrt64( FT_Int64 x );
+
+#endif /* OLD_CALCS */
+
#else /* LONG64 */
typedef struct FT_Int64_
@@ -50,21 +59,34 @@
#define MUL_64( x, y, z ) FT_MulTo64( x, y, &z )
#define DIV_64( x, y ) FT_Div64by32( &x, y )
- BASE_DEF
+ EXPORT_DEF
void FT_Add64 ( FT_Int64* x, FT_Int64* y, FT_Int64* z );
- BASE_DEF
+
+ EXPORT_DEF
void FT_MulTo64 ( FT_Int32 x, FT_Int32 y, FT_Int64* z );
- BASE_DEF
+
+ EXPORT_DEF
FT_Int32 FT_Div64by32( FT_Int64* x, FT_Int32 y );
+#ifdef FT_CONFIG_OPTION_OLD_CALCS
+#define SQRT_64( z ) FT_Sqrt64( &z )
+
+ EXPORT_DEF
+ FT_Int32 FT_Sqrt64( FT_Int64* x );
+
+#endif /* OLD_CALC */
+
#endif /* LONG64 */
+#ifndef FT_CONFIG_OPTION_OLD_CALCS
+
#define SQRT_32( x ) FT_Sqrt32( x )
BASE_DEF
FT_Int32 FT_Sqrt32( FT_Int32 l );
+#endif
/*************************************************************************/
/* */