RISCVVector.h

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// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
// SPDX-FileCopyrightText: 2026 Jorrit Rouwe
// SPDX-License-Identifier: MIT
 
#pragma once
 
JPH_NAMESPACE_BEGIN
 
#ifdef JPH_USE_RVV
 
template <unsigned IndexX, unsigned IndexY, unsigned IndexZ, unsigned IndexW>
JPH_INLINE vfloat32m1_t RVVShuffleFloat32x4(vfloat32m1_t inV0, vfloat32m1_t inV1)
{
    vfloat32m2_t combined = __riscv_vlmul_ext_v_f32m1_f32m2(inV0);
    combined = __riscv_vslideup_vx_f32m2(combined, __riscv_vlmul_ext_v_f32m1_f32m2(inV1), 4, 8);
 
    const uint32 indices_raw[4] = { IndexX, IndexY, IndexZ, IndexW };
    const vuint32m1_t v_indices_m1 = __riscv_vle32_v_u32m1(indices_raw, 4);
    const vuint32m2_t v_indices_m2 = __riscv_vlmul_ext_v_u32m1_u32m2(v_indices_m1);
 
    const vfloat32m2_t gathered_m2 = __riscv_vrgather_vv_f32m2(combined, v_indices_m2, 4);
    return __riscv_vlmul_trunc_v_f32m2_f32m1(gathered_m2);
}
 
template <>
JPH_INLINE vfloat32m1_t RVVShuffleFloat32x4<0, 1, 2, 3>(vfloat32m1_t inV0, vfloat32m1_t inV1)
{
    return inV0;
}
 
template <>
JPH_INLINE vfloat32m1_t RVVShuffleFloat32x4<0, 1, 4, 5>(vfloat32m1_t inV0, vfloat32m1_t inV1)
{
    vfloat32m1_t result = inV0;
    return __riscv_vslideup_vx_f32m1(result, inV1, 2, 4);   
}
 
template <>
JPH_INLINE vfloat32m1_t RVVShuffleFloat32x4<1, 0, 3, 2>(vfloat32m1_t inV0, vfloat32m1_t inV1)
{
    // Avoids m2 extension overhead that the default implementation of RVVShuffleFloat32x4 has
    const uint32 indices_raw[4] = { 1, 0, 3, 2 };
    const vuint32m1_t indices = __riscv_vle32_v_u32m1(indices_raw, 4);
    return __riscv_vrgather_vv_f32m1(inV0, indices, 4);
}
 
template <>
JPH_INLINE vfloat32m1_t RVVShuffleFloat32x4<2, 3, 0, 1>(vfloat32m1_t inV0, vfloat32m1_t inV1)
{
    vfloat32m1_t upper = __riscv_vslidedown_vx_f32m1(inV0, 2, 4);
    return __riscv_vslideup_vx_f32m1(upper, inV0, 2, 4);
}
 
template <>
JPH_INLINE vfloat32m1_t RVVShuffleFloat32x4<2, 3, 6, 7>(vfloat32m1_t inV0, vfloat32m1_t inV1)
{
    return __riscv_vslidedown_vx_f32m1_tu(inV1, inV0, 2, 2);
}
 
template <>
JPH_INLINE vfloat32m1_t RVVShuffleFloat32x4<4, 5, 6, 7>(vfloat32m1_t inV0, vfloat32m1_t inV1)
{
    return inV1;
}
 
template <>
JPH_INLINE vfloat32m1_t RVVShuffleFloat32x4<0, 2, 4, 6>(vfloat32m1_t inV0, vfloat32m1_t inV1)
{
    vfloat32m2_t combined = __riscv_vlmul_ext_v_f32m1_f32m2(inV0);
    combined = __riscv_vslideup_vx_f32m2(combined, __riscv_vlmul_ext_v_f32m1_f32m2(inV1), 4, 8);
 
    vuint64m2_t combined_u64 = __riscv_vreinterpret_v_u32m2_u64m2(__riscv_vreinterpret_v_f32m2_u32m2(combined));
 
    // vnsrl extracts lower 32 bits from all 4 u64 elements -> [0, 2, 4, 6]
    vuint32m1_t result = __riscv_vnsrl_wx_u32m1(combined_u64, 0, 4);
 
    return __riscv_vreinterpret_v_u32m1_f32m1(result);
}
 
template <>
JPH_INLINE vfloat32m1_t RVVShuffleFloat32x4<1, 3, 5, 7>(vfloat32m1_t inV0, vfloat32m1_t inV1)
{
    vfloat32m2_t combined = __riscv_vlmul_ext_v_f32m1_f32m2(inV0);
    combined = __riscv_vslideup_vx_f32m2(combined, __riscv_vlmul_ext_v_f32m1_f32m2(inV1), 4, 8);
 
    vuint64m2_t combined_u64 = __riscv_vreinterpret_v_u32m2_u64m2(__riscv_vreinterpret_v_f32m2_u32m2(combined));
 
    // vnsrl with shift=32 extracts upper 32 bits from all 4 u64 elements -> [1, 3, 5, 7]
    vuint32m1_t result = __riscv_vnsrl_wx_u32m1(combined_u64, 32, 4);
 
    return __riscv_vreinterpret_v_u32m1_f32m1(result);
}
 
JPH_INLINE float RVVSumElementsFloat32x4(vfloat32m1_t inV)
{
#ifdef JPH_CROSS_PLATFORM_DETERMINISTIC
    const vfloat32m1_t shift1 = __riscv_vslidedown_vx_f32m1(inV, 1, 4);
    const vfloat32m1_t sum_pairs = __riscv_vfadd_vv_f32m1(inV, shift1, 4);
    const vfloat32m1_t shift2 = __riscv_vslidedown_vx_f32m1(sum_pairs, 2, 4);
    const vfloat32m1_t sum = __riscv_vfadd_vv_f32m1(sum_pairs, shift2, 4);
#else
    const vfloat32m1_t zeros = __riscv_vfmv_v_f_f32m1(0.0f, 4);
    const vfloat32m1_t sum = __riscv_vfredusum_vs_f32m1_f32m1(inV, zeros, 4);
#endif
    return __riscv_vfmv_f_s_f32m1_f32(sum);
}
 
#endif // JPH_USE_RVV
 
JPH_NAMESPACE_END