Removed some branching

This commit is contained in:
Christophe Riccio 2011-01-31 18:14:23 +00:00
parent cb05c4c00f
commit b02890730b
4 changed files with 29 additions and 22 deletions

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@ -26,7 +26,7 @@ namespace glm
template <typename genFIType>
genFIType abs(genFIType const & x);
//! Returns 1.0 if x > 0, 0.0 if x = 0, or -1.0 if x < 0.
//! Returns 1.0 if x > 0, 0.0 if x == 0, or -1.0 if x < 0.
//! (From GLSL 1.30.08 specification, section 8.3)
template <typename genFIType>
genFIType sign(genFIType const & x);

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@ -189,7 +189,7 @@ namespace glm
inline genType trunc(genType const & x)
{
GLM_STATIC_ASSERT(detail::type<genType>::is_float, "'trunc' only accept floating-point inputs");
return x < 0 ? -floor(-x) : floor(x);;
return x < 0 ? -floor(-x) : floor(x);
}
template <typename valType>

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@ -34,7 +34,7 @@ namespace detail{
static const ieee754_QNAN absMask;
static const __m128 abs4Mask = _mm_set_ps1(absMask.f);
//static const __m128 _epi32_sign_mask = _mm_castsi128_ps(_mm_set1_epi32(0x80000000));
static const __m128 _epi32_sign_mask = _mm_castsi128_ps(_mm_set1_epi32(0x80000000));
//static const __m128 _epi32_inv_sign_mask = _mm_castsi128_ps(_mm_set1_epi32(0x7FFFFFFF));
//static const __m128 _epi32_mant_mask = _mm_castsi128_ps(_mm_set1_epi32(0x7F800000));
//static const __m128 _epi32_inv_mant_mask = _mm_castsi128_ps(_mm_set1_epi32(0x807FFFFF));
@ -130,24 +130,16 @@ inline __m128 sse_abs_ps(__m128 x)
inline __m128 sse_sgn_ps(__m128 x)
{
//__m128 cmp0 = _mm_cmpeq_ps(x, zero);
//__m128 cmp1 = _mm_cmple_ps(x, zero);
//__m128 cmp2 = _mm_cmpge_ps(x, zero);
__m128 Neg = _mm_set1_ps(-1.0f);
__m128 Pos = _mm_set1_ps(1.0f);
__m128 result;
__m128 cmp0 = _mm_cmpeq_ps(x, glm::detail::zero);
if(_mm_movemask_ps(cmp0) == 0)
result = glm::detail::zero;
else
{
__m128 cmp1 = _mm_cmpge_ps(x, glm::detail::zero);
//__m128 cmp2 = _mm_cmple_ps(x, glm::detail::zero);
if(_mm_movemask_ps(cmp1) > 0)
result = glm::detail::one;
else //if(_mm_movemask_ps(cmp2) > 0)
result = glm::detail::minus_one;
}
return result;
__m128 Cmp0 = _mm_cmplt_ps(x, zero);
__m128 Cmp1 = _mm_cmpgt_ps(x, zero);
__m128 And0 = _mm_and_ps(Cmp0, Neg);
__m128 And1 = _mm_and_ps(Cmp1, Pos);
return _mm_or_ps(And0, And1);
}
//floor
@ -170,7 +162,7 @@ inline __m128 _mm_trc_ps(__m128 v)
//round
inline __m128 sse_rnd_ps(__m128 x)
{
__m128 and0;// = _mm_and_ps(glm::detail::_epi32_sign_mask, x);
__m128 and0 = _mm_and_ps(glm::detail::_epi32_sign_mask, x);
__m128 or0 = _mm_or_ps(and0, glm::detail::_ps_2pow23);
__m128 add0 = _mm_add_ps(x, or0);
__m128 sub0 = _mm_sub_ps(add0, or0);

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@ -280,6 +280,11 @@ namespace glm
return Result;
}
// Other possible implementation
//float abs(float a)
//{
// return max(-a, a);
//}
detail::fvec4SIMD abs
(
detail::fvec4SIMD const & x
@ -309,7 +314,17 @@ namespace glm
detail::fvec4SIMD const & x
)
{
return detail::sse_flr_ps(detail::sse_abs_ps(x.Data));
__m128 Flr0 = detail::sse_flr_ps(_mm_sub_ps(_mm_setzero_ps(), x.Data));
__m128 Sub0 = _mm_sub_ps(Flr0, x.Data);
__m128 Flr1 = detail::sse_flr_ps(x.Data);
__m128 Cmp0 = _mm_cmplt_ps(x.Data, glm::detail::zero);
__m128 Cmp1 = _mm_cmpnlt_ps(x.Data, glm::detail::zero);
__m128 And0 = _mm_and_ps(Flr0, Cmp0);
__m128 And1 = _mm_and_ps(Flr1, Cmp1);
return _mm_or_ps(And0, And1);
}
inline detail::fvec4SIMD round