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Need explicit vector division #30

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walbourn opened this issue Jun 9, 2016 · 3 comments
Closed

Need explicit vector division #30

walbourn opened this issue Jun 9, 2016 · 3 comments
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walbourn commented Jun 9, 2016

The original xboxmath library did not include an XMVectorDivide. It instead expected client code to use multiply-by-reciprocal. As there's an explicit divide function in SSE/SSE2, the new method is needed.
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walbourn commented Jun 9, 2016

This was fixed for XNAMath 2.03

@walbourn walbourn closed this as completed Jun 9, 2016
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walbourn commented Jun 9, 2016 •
edited

The ARM 32-bit platform using ARMv7 does not have an explicit divide operation in ARM NEON, so XMVectorDivide is implemented with 2 iterations of Newton-Raphson refinement of the reciprocal

@walbourn walbourn self-assigned this Jun 9, 2016
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walbourn commented Jun 9, 2016 •
edited

ARM64 which requires ARMv8 has a new ARM NEON intrinsic vdivq_f32 which can be used to implement XMVectorDivide rather than using the multiply-by-reciprocal

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