diff --git a/glm/detail/type_vec4_simd.inl b/glm/detail/type_vec4_simd.inl index 149c413e..8d8b562f 100644 --- a/glm/detail/type_vec4_simd.inl +++ b/glm/detail/type_vec4_simd.inl @@ -577,7 +577,20 @@ namespace detail { static vec<4, float, Q> call(vec<4, float, Q> const& a, vec<4, float, Q> const& b) { vec<4, float, Q> Result; +#if GLM_ARCH & GLM_ARCH_ARMV8_BIT Result.data = vdivq_f32(a.data, b.data); +#else + /* Arm assembler reference: + * + * The Newton-Raphson iteration: x[n+1] = x[n] * (2 - d * x[n]) + * converges to (1/d) if x0 is the result of VRECPE applied to d. + * + * Note: The precision usually improves with two interactions, but more than two iterations are not helpful. */ + float32x4_t x = vrecpeq_f32(b.data); + x = vmulq_f32(vrecpsq_f32(b.data, x), x); + x = vmulq_f32(vrecpsq_f32(b.data, x), x); + Result.data = vmulq_f32(a.data, x); +#endif return Result; } };