makarna/pkg/backend/cuda/cuda_common.cuh

#ifndef MAKARNA_CUDA_COMMON_CUH
#define MAKARNA_CUDA_COMMON_CUH

#include "kernels.h"
#define CUDA_API_PER_THREAD_DEFAULT_STREAM 1
#include <cuda_runtime.h>
#include <math.h>
#include <stdio.h>

#define CHECK_CUDA(call) \
    do { \
        cudaError_t err = call; \
        if (err != cudaSuccess) { \
            fprintf(stderr, "CUDA error at %s:%d: %s\n", __FILE__, __LINE__, cudaGetErrorString(err)); \
            return 1; \
        } \
    } while (0)

// ============================================================
// FP16 -> FP32 conversion (device function)
// ============================================================
__device__ __forceinline__ float fp16_to_fp32(unsigned short h) {
    unsigned int sign = (h & 0x8000) << 16;
    unsigned int exp = (h & 0x7C00) >> 10;
    unsigned int mant = h & 0x03FF;
    
    if (exp > 0 && exp < 0x1F) {
        // Normalized
        unsigned int bits = sign | ((exp + 112) << 23) | (mant << 13);
        return __int_as_float(bits);
    }
    if (exp == 0) {
        if (mant == 0) return __int_as_float(sign); // Zero
        // Denorm - rare case, simplified
        float m = (float)mant / 1024.0f;
        float val = m * 6.103515625e-05f; // 2^-14
        return sign ? -val : val;
    }
    // Inf/NaN
    return mant == 0 ? __int_as_float(sign | 0x7F800000) : __int_as_float(sign | 0x7FC00000);
}

#endif