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Fixed glm::detail::nextafter implementation

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This commit is contained in:
Christophe Riccio 2011-05-06 12:12:22 +01:00
parent 6efc6940b8
commit 3d7d4dc9c2
1 changed files with 104 additions and 101 deletions
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205
glm/gtx/ulp.inl
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@ -20,8 +20,8 @@
* is preserved. * is preserved.
* ==================================================== * ====================================================
*/ */
/*
#define EXTRACT_WORDS(ix0,ix1,d) \ #define GLM_EXTRACT_WORDS(ix0,ix1,d) \
do { \ do { \
ieee_double_shape_type ew_u; \ ieee_double_shape_type ew_u; \
ew_u.value = (d); \ ew_u.value = (d); \
@ -29,21 +29,21 @@ do { \
(ix1) = ew_u.parts.lsw; \ (ix1) = ew_u.parts.lsw; \
} while (0) } while (0)
#define GET_FLOAT_WORD(i,d) \ #define GLM_GET_FLOAT_WORD(i,d) \
do { \ do { \
ieee_float_shape_type gf_u; \ ieee_float_shape_type gf_u; \
gf_u.value = (d); \ gf_u.value = (d); \
(i) = gf_u.word; \ (i) = gf_u.word; \
} while (0) } while (0)
#define SET_FLOAT_WORD(d,i) \ #define GLM_SET_FLOAT_WORD(d,i) \
do { \ do { \
ieee_float_shape_type sf_u; \ ieee_float_shape_type sf_u; \
sf_u.word = (i); \ sf_u.word = (i); \
(d) = sf_u.value; \ (d) = sf_u.value; \
} while (0) } while (0)
#define INSERT_WORDS(d,ix0,ix1) \ #define GLM_INSERT_WORDS(d,ix0,ix1) \
do { \ do { \
ieee_double_shape_type iw_u; \ ieee_double_shape_type iw_u; \
iw_u.parts.msw = (ix0); \ iw_u.parts.msw = (ix0); \
@ -51,113 +51,116 @@ do { \
(d) = iw_u.value; \ (d) = iw_u.value; \
} while (0) } while (0)
float nextafterf(float x, float y) namespace glm{
namespace detail
{ {
volatile float t; GLM_FUNC_QUALIFIER float nextafterf(float x, float y)
int32_t hx,hy,ix,iy; {
volatile float t;
glm::int32 hx, hy, ix, iy;
GET_FLOAT_WORD(hx,x); GLM_GET_FLOAT_WORD(hx,x);
GET_FLOAT_WORD(hy,y); GLM_GET_FLOAT_WORD(hy,y);
ix = hx&0x7fffffff; // |x| ix = hx&0x7fffffff; // |x|
iy = hy&0x7fffffff; // |y| iy = hy&0x7fffffff; // |y|
if((ix>0x7f800000) || // x is nan if((ix>0x7f800000) || // x is nan
(iy>0x7f800000)) // y is nan (iy>0x7f800000)) // y is nan
return x+y; return x+y;
if(x==y) return y; // x=y, return y if(x==y) return y; // x=y, return y
if(ix==0) { // x == 0 if(ix==0) { // x == 0
SET_FLOAT_WORD(x,(hy&0x80000000)|1);// return +-minsubnormal GLM_SET_FLOAT_WORD(x,(hy&0x80000000)|1);// return +-minsubnormal
t = x*x; t = x*x;
if(t==x) return t; else return x; // raise underflow flag if(t==x) return t; else return x; // raise underflow flag
} }
if(hx>=0) { // x > 0 if(hx>=0) { // x > 0
if(hx>hy) { // x > y, x -= ulp if(hx>hy) { // x > y, x -= ulp
hx -= 1; hx -= 1;
} else { // x < y, x += ulp } else { // x < y, x += ulp
hx += 1; hx += 1;
} }
} else { // x < 0 } else { // x < 0
if(hy>=0||hx>hy){ // x < y, x -= ulp if(hy>=0||hx>hy){ // x < y, x -= ulp
hx -= 1; hx -= 1;
} else { // x > y, x += ulp } else { // x > y, x += ulp
hx += 1; hx += 1;
} }
} }
hy = hx&0x7f800000; hy = hx&0x7f800000;
if(hy>=0x7f800000) return x+x; // overflow if(hy>=0x7f800000) return x+x; // overflow
if(hy<0x00800000) { // underflow if(hy<0x00800000) { // underflow
t = x*x; t = x*x;
if(t!=x) { // raise underflow flag if(t!=x) { // raise underflow flag
SET_FLOAT_WORD(y,hx); GLM_SET_FLOAT_WORD(y,hx);
return y; return y;
} }
} }
SET_FLOAT_WORD(x,hx); GLM_SET_FLOAT_WORD(x,hx);
return x; return x;
} }
*/
/*
double nextafter(double x, double y)
{
volatile double t;
int32_t hx,hy,ix,iy;
u_int32_t lx,ly;
EXTRACT_WORDS(hx,lx,x); GLM_FUNC_QUALIFIER double nextafter(double x, double y)
EXTRACT_WORDS(hy,ly,y); {
ix = hx&0x7fffffff; // |x| volatile double t;
iy = hy&0x7fffffff; // |y| glm::int32 hx, hy, ix, iy;
glm::uint32 lx, ly;
if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || // x is nan GLM_EXTRACT_WORDS(hx, lx, x);
((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0)) // y is nan GLM_EXTRACT_WORDS(hy, ly, y);
return x+y; ix = hx & 0x7fffffff; // |x|
if(x==y) return y; // x=y, return y iy = hy & 0x7fffffff; // |y|
if((ix|lx)==0) { // x == 0
INSERT_WORDS(x,hy&0x80000000,1); // return +-minsubnormal if(((ix>=0x7ff00000)&&((ix-0x7ff00000)|lx)!=0) || // x is nan
t = x*x; ((iy>=0x7ff00000)&&((iy-0x7ff00000)|ly)!=0)) // y is nan
if(t==x) return t; else return x; // raise underflow flag return x+y;
} if(x==y) return y; // x=y, return y
if(hx>=0) { // x > 0 if((ix|lx)==0) { // x == 0
if(hx>hy||((hx==hy)&&(lx>ly))) { // x > y, x -= ulp GLM_INSERT_WORDS(x, hy & 0x80000000, 1); // return +-minsubnormal
if(lx==0) hx -= 1; t = x*x;
lx -= 1; if(t==x) return t; else return x; // raise underflow flag
} else { // x < y, x += ulp }
lx += 1; if(hx>=0) { // x > 0
if(lx==0) hx += 1; if(hx>hy||((hx==hy)&&(lx>ly))) { // x > y, x -= ulp
} if(lx==0) hx -= 1;
} else { // x < 0 lx -= 1;
if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){// x < y, x -= ulp } else { // x < y, x += ulp
if(lx==0) hx -= 1; lx += 1;
lx -= 1; if(lx==0) hx += 1;
} else { // x > y, x += ulp }
lx += 1; } else { // x < 0
if(lx==0) hx += 1; if(hy>=0||hx>hy||((hx==hy)&&(lx>ly))){// x < y, x -= ulp
} if(lx==0) hx -= 1;
} lx -= 1;
hy = hx&0x7ff00000; } else { // x > y, x += ulp
if(hy>=0x7ff00000) return x+x; // overflow lx += 1;
if(hy<0x00100000) { // underflow if(lx==0) hx += 1;
t = x*x; }
if(t!=x) { // raise underflow flag }
INSERT_WORDS(y,hx,lx); hy = hx&0x7ff00000;
return y; if(hy>=0x7ff00000) return x+x; // overflow
} if(hy<0x00100000) { // underflow
} t = x*x;
INSERT_WORDS(x,hx,lx); if(t!=x) { // raise underflow flag
return x; GLM_INSERT_WORDS(y,hx,lx);
} return y;
*/ }
}
GLM_INSERT_WORDS(x,hx,lx);
return x;
}
}//namespace detail
}//namespace glm
#if(GLM_COMPILER & GLM_COMPILER_VC) #if(GLM_COMPILER & GLM_COMPILER_VC)
# if(GLM_MODEL == GLM_MODEL_32) # if(GLM_MODEL == GLM_MODEL_32)
# define GLM_NEXT_AFTER_FLT(x, toward) (float)_nextafter(x, float(toward)) # define GLM_NEXT_AFTER_FLT(x, toward) glm::detail::nextafter((x), (toward))
# else # else
# define GLM_NEXT_AFTER_FLT(x, toward) _nextafterf(x, toward) # define GLM_NEXT_AFTER_FLT(x, toward) _nextafterf((x), (toward))
# endif # endif
# define GLM_NEXT_AFTER_DBL(x, toward) _nextafter(x, toward) # define GLM_NEXT_AFTER_DBL(x, toward) _nextafter((x), (toward))
#else #else
# define GLM_NEXT_AFTER_FLT(x, toward) nextafterf(x, toward) # define GLM_NEXT_AFTER_FLT(x, toward) nextafterf((x), (toward))
# define GLM_NEXT_AFTER_DBL(x, toward) nextafter(x, toward) # define GLM_NEXT_AFTER_DBL(x, toward) nextafter((x), (toward))
#endif #endif
namespace glm{ namespace glm{