更新libclamav库1.0.0版本

clamav/libclamav_rust/.cargo/vendor/half/src/binary16/convert.rs

@@ -0,0 +1,501 @@
+#![allow(dead_code, unused_imports)]
+use crate::leading_zeros::leading_zeros_u16;
+use core::mem;
+
+macro_rules! convert_fn {
+    (fn $name:ident($var:ident : $vartype:ty) -> $restype:ty {
+            if feature("f16c") { $f16c:expr }
+            else { $fallback:expr }}) => {
+        #[inline]
+        pub(crate) fn $name($var: $vartype) -> $restype {
+            // Use CPU feature detection if using std
+            #[cfg(all(
+                feature = "use-intrinsics",
+                feature = "std",
+                any(target_arch = "x86", target_arch = "x86_64"),
+                not(target_feature = "f16c")
+            ))]
+            {
+                if is_x86_feature_detected!("f16c") {
+                    $f16c
+                } else {
+                    $fallback
+                }
+            }
+            // Use intrinsics directly when a compile target or using no_std
+            #[cfg(all(
+                feature = "use-intrinsics",
+                any(target_arch = "x86", target_arch = "x86_64"),
+                target_feature = "f16c"
+            ))]
+            {
+                $f16c
+            }
+            // Fallback to software
+            #[cfg(any(
+                not(feature = "use-intrinsics"),
+                not(any(target_arch = "x86", target_arch = "x86_64")),
+                all(not(feature = "std"), not(target_feature = "f16c"))
+            ))]
+            {
+                $fallback
+            }
+        }
+    };
+}
+
+convert_fn! {
+    fn f32_to_f16(f: f32) -> u16 {
+        if feature("f16c") {
+            unsafe { x86::f32_to_f16_x86_f16c(f) }
+        } else {
+            f32_to_f16_fallback(f)
+        }
+    }
+}
+
+convert_fn! {
+    fn f64_to_f16(f: f64) -> u16 {
+        if feature("f16c") {
+            unsafe { x86::f32_to_f16_x86_f16c(f as f32) }
+        } else {
+            f64_to_f16_fallback(f)
+        }
+    }
+}
+
+convert_fn! {
+    fn f16_to_f32(i: u16) -> f32 {
+        if feature("f16c") {
+            unsafe { x86::f16_to_f32_x86_f16c(i) }
+        } else {
+            f16_to_f32_fallback(i)
+        }
+    }
+}
+
+convert_fn! {
+    fn f16_to_f64(i: u16) -> f64 {
+        if feature("f16c") {
+            unsafe { x86::f16_to_f32_x86_f16c(i) as f64 }
+        } else {
+            f16_to_f64_fallback(i)
+        }
+    }
+}
+
+// TODO: While SIMD versions are faster, further improvements can be made by doing runtime feature
+// detection once at beginning of convert slice method, rather than per chunk
+
+convert_fn! {
+    fn f32x4_to_f16x4(f: &[f32]) -> [u16; 4] {
+        if feature("f16c") {
+            unsafe { x86::f32x4_to_f16x4_x86_f16c(f) }
+        } else {
+            f32x4_to_f16x4_fallback(f)
+        }
+    }
+}
+
+convert_fn! {
+    fn f16x4_to_f32x4(i: &[u16]) -> [f32; 4] {
+        if feature("f16c") {
+            unsafe { x86::f16x4_to_f32x4_x86_f16c(i) }
+        } else {
+            f16x4_to_f32x4_fallback(i)
+        }
+    }
+}
+
+convert_fn! {
+    fn f64x4_to_f16x4(f: &[f64]) -> [u16; 4] {
+        if feature("f16c") {
+            unsafe { x86::f64x4_to_f16x4_x86_f16c(f) }
+        } else {
+            f64x4_to_f16x4_fallback(f)
+        }
+    }
+}
+
+convert_fn! {
+    fn f16x4_to_f64x4(i: &[u16]) -> [f64; 4] {
+        if feature("f16c") {
+            unsafe { x86::f16x4_to_f64x4_x86_f16c(i) }
+        } else {
+            f16x4_to_f64x4_fallback(i)
+        }
+    }
+}
+
+/////////////// Fallbacks ////////////////
+
+// In the below functions, round to nearest, with ties to even.
+// Let us call the most significant bit that will be shifted out the round_bit.
+//
+// Round up if either
+//  a) Removed part > tie.
+//     (mantissa & round_bit) != 0 && (mantissa & (round_bit - 1)) != 0
+//  b) Removed part == tie, and retained part is odd.
+//     (mantissa & round_bit) != 0 && (mantissa & (2 * round_bit)) != 0
+// (If removed part == tie and retained part is even, do not round up.)
+// These two conditions can be combined into one:
+//     (mantissa & round_bit) != 0 && (mantissa & ((round_bit - 1) | (2 * round_bit))) != 0
+// which can be simplified into
+//     (mantissa & round_bit) != 0 && (mantissa & (3 * round_bit - 1)) != 0
+
+pub(crate) const fn f32_to_f16_fallback(value: f32) -> u16 {
+    // TODO: Replace mem::transmute with to_bits() once to_bits is const-stabilized
+    // Convert to raw bytes
+    let x: u32 = unsafe { mem::transmute(value) };
+
+    // Extract IEEE754 components
+    let sign = x & 0x8000_0000u32;
+    let exp = x & 0x7F80_0000u32;
+    let man = x & 0x007F_FFFFu32;
+
+    // Check for all exponent bits being set, which is Infinity or NaN
+    if exp == 0x7F80_0000u32 {
+        // Set mantissa MSB for NaN (and also keep shifted mantissa bits)
+        let nan_bit = if man == 0 { 0 } else { 0x0200u32 };
+        return ((sign >> 16) | 0x7C00u32 | nan_bit | (man >> 13)) as u16;
+    }
+
+    // The number is normalized, start assembling half precision version
+    let half_sign = sign >> 16;
+    // Unbias the exponent, then bias for half precision
+    let unbiased_exp = ((exp >> 23) as i32) - 127;
+    let half_exp = unbiased_exp + 15;
+
+    // Check for exponent overflow, return +infinity
+    if half_exp >= 0x1F {
+        return (half_sign | 0x7C00u32) as u16;
+    }
+
+    // Check for underflow
+    if half_exp <= 0 {
+        // Check mantissa for what we can do
+        if 14 - half_exp > 24 {
+            // No rounding possibility, so this is a full underflow, return signed zero
+            return half_sign as u16;
+        }
+        // Don't forget about hidden leading mantissa bit when assembling mantissa
+        let man = man | 0x0080_0000u32;
+        let mut half_man = man >> (14 - half_exp);
+        // Check for rounding (see comment above functions)
+        let round_bit = 1 << (13 - half_exp);
+        if (man & round_bit) != 0 && (man & (3 * round_bit - 1)) != 0 {
+            half_man += 1;
+        }
+        // No exponent for subnormals
+        return (half_sign | half_man) as u16;
+    }
+
+    // Rebias the exponent
+    let half_exp = (half_exp as u32) << 10;
+    let half_man = man >> 13;
+    // Check for rounding (see comment above functions)
+    let round_bit = 0x0000_1000u32;
+    if (man & round_bit) != 0 && (man & (3 * round_bit - 1)) != 0 {
+        // Round it
+        ((half_sign | half_exp | half_man) + 1) as u16
+    } else {
+        (half_sign | half_exp | half_man) as u16
+    }
+}
+
+pub(crate) const fn f64_to_f16_fallback(value: f64) -> u16 {
+    // Convert to raw bytes, truncating the last 32-bits of mantissa; that precision will always
+    // be lost on half-precision.
+    // TODO: Replace mem::transmute with to_bits() once to_bits is const-stabilized
+    let val: u64 = unsafe { mem::transmute(value) };
+    let x = (val >> 32) as u32;
+
+    // Extract IEEE754 components
+    let sign = x & 0x8000_0000u32;
+    let exp = x & 0x7FF0_0000u32;
+    let man = x & 0x000F_FFFFu32;
+
+    // Check for all exponent bits being set, which is Infinity or NaN
+    if exp == 0x7FF0_0000u32 {
+        // Set mantissa MSB for NaN (and also keep shifted mantissa bits).
+        // We also have to check the last 32 bits.
+        let nan_bit = if man == 0 && (val as u32 == 0) {
+            0
+        } else {
+            0x0200u32
+        };
+        return ((sign >> 16) | 0x7C00u32 | nan_bit | (man >> 10)) as u16;
+    }
+
+    // The number is normalized, start assembling half precision version
+    let half_sign = sign >> 16;
+    // Unbias the exponent, then bias for half precision
+    let unbiased_exp = ((exp >> 20) as i64) - 1023;
+    let half_exp = unbiased_exp + 15;
+
+    // Check for exponent overflow, return +infinity
+    if half_exp >= 0x1F {
+        return (half_sign | 0x7C00u32) as u16;
+    }
+
+    // Check for underflow
+    if half_exp <= 0 {
+        // Check mantissa for what we can do
+        if 10 - half_exp > 21 {
+            // No rounding possibility, so this is a full underflow, return signed zero
+            return half_sign as u16;
+        }
+        // Don't forget about hidden leading mantissa bit when assembling mantissa
+        let man = man | 0x0010_0000u32;
+        let mut half_man = man >> (11 - half_exp);
+        // Check for rounding (see comment above functions)
+        let round_bit = 1 << (10 - half_exp);
+        if (man & round_bit) != 0 && (man & (3 * round_bit - 1)) != 0 {
+            half_man += 1;
+        }
+        // No exponent for subnormals
+        return (half_sign | half_man) as u16;
+    }
+
+    // Rebias the exponent
+    let half_exp = (half_exp as u32) << 10;
+    let half_man = man >> 10;
+    // Check for rounding (see comment above functions)
+    let round_bit = 0x0000_0200u32;
+    if (man & round_bit) != 0 && (man & (3 * round_bit - 1)) != 0 {
+        // Round it
+        ((half_sign | half_exp | half_man) + 1) as u16
+    } else {
+        (half_sign | half_exp | half_man) as u16
+    }
+}
+
+pub(crate) const fn f16_to_f32_fallback(i: u16) -> f32 {
+    // Check for signed zero
+    // TODO: Replace mem::transmute with from_bits() once from_bits is const-stabilized
+    if i & 0x7FFFu16 == 0 {
+        return unsafe { mem::transmute((i as u32) << 16) };
+    }
+
+    let half_sign = (i & 0x8000u16) as u32;
+    let half_exp = (i & 0x7C00u16) as u32;
+    let half_man = (i & 0x03FFu16) as u32;
+
+    // Check for an infinity or NaN when all exponent bits set
+    if half_exp == 0x7C00u32 {
+        // Check for signed infinity if mantissa is zero
+        if half_man == 0 {
+            return unsafe { mem::transmute((half_sign << 16) | 0x7F80_0000u32) };
+        } else {
+            // NaN, keep current mantissa but also set most significiant mantissa bit
+            return unsafe {
+                mem::transmute((half_sign << 16) | 0x7FC0_0000u32 | (half_man << 13))
+            };
+        }
+    }
+
+    // Calculate single-precision components with adjusted exponent
+    let sign = half_sign << 16;
+    // Unbias exponent
+    let unbiased_exp = ((half_exp as i32) >> 10) - 15;
+
+    // Check for subnormals, which will be normalized by adjusting exponent
+    if half_exp == 0 {
+        // Calculate how much to adjust the exponent by
+        let e = leading_zeros_u16(half_man as u16) - 6;
+
+        // Rebias and adjust exponent
+        let exp = (127 - 15 - e) << 23;
+        let man = (half_man << (14 + e)) & 0x7F_FF_FFu32;
+        return unsafe { mem::transmute(sign | exp | man) };
+    }
+
+    // Rebias exponent for a normalized normal
+    let exp = ((unbiased_exp + 127) as u32) << 23;
+    let man = (half_man & 0x03FFu32) << 13;
+    unsafe { mem::transmute(sign | exp | man) }
+}
+
+pub(crate) const fn f16_to_f64_fallback(i: u16) -> f64 {
+    // Check for signed zero
+    // TODO: Replace mem::transmute with from_bits() once from_bits is const-stabilized
+    if i & 0x7FFFu16 == 0 {
+        return unsafe { mem::transmute((i as u64) << 48) };
+    }
+
+    let half_sign = (i & 0x8000u16) as u64;
+    let half_exp = (i & 0x7C00u16) as u64;
+    let half_man = (i & 0x03FFu16) as u64;
+
+    // Check for an infinity or NaN when all exponent bits set
+    if half_exp == 0x7C00u64 {
+        // Check for signed infinity if mantissa is zero
+        if half_man == 0 {
+            return unsafe { mem::transmute((half_sign << 48) | 0x7FF0_0000_0000_0000u64) };
+        } else {
+            // NaN, keep current mantissa but also set most significiant mantissa bit
+            return unsafe {
+                mem::transmute((half_sign << 48) | 0x7FF8_0000_0000_0000u64 | (half_man << 42))
+            };
+        }
+    }
+
+    // Calculate double-precision components with adjusted exponent
+    let sign = half_sign << 48;
+    // Unbias exponent
+    let unbiased_exp = ((half_exp as i64) >> 10) - 15;
+
+    // Check for subnormals, which will be normalized by adjusting exponent
+    if half_exp == 0 {
+        // Calculate how much to adjust the exponent by
+        let e = leading_zeros_u16(half_man as u16) - 6;
+
+        // Rebias and adjust exponent
+        let exp = ((1023 - 15 - e) as u64) << 52;
+        let man = (half_man << (43 + e)) & 0xF_FFFF_FFFF_FFFFu64;
+        return unsafe { mem::transmute(sign | exp | man) };
+    }
+
+    // Rebias exponent for a normalized normal
+    let exp = ((unbiased_exp + 1023) as u64) << 52;
+    let man = (half_man & 0x03FFu64) << 42;
+    unsafe { mem::transmute(sign | exp | man) }
+}
+
+#[inline]
+fn f16x4_to_f32x4_fallback(v: &[u16]) -> [f32; 4] {
+    debug_assert!(v.len() >= 4);
+
+    [
+        f16_to_f32_fallback(v[0]),
+        f16_to_f32_fallback(v[1]),
+        f16_to_f32_fallback(v[2]),
+        f16_to_f32_fallback(v[3]),
+    ]
+}
+
+#[inline]
+fn f32x4_to_f16x4_fallback(v: &[f32]) -> [u16; 4] {
+    debug_assert!(v.len() >= 4);
+
+    [
+        f32_to_f16_fallback(v[0]),
+        f32_to_f16_fallback(v[1]),
+        f32_to_f16_fallback(v[2]),
+        f32_to_f16_fallback(v[3]),
+    ]
+}
+
+#[inline]
+fn f16x4_to_f64x4_fallback(v: &[u16]) -> [f64; 4] {
+    debug_assert!(v.len() >= 4);
+
+    [
+        f16_to_f64_fallback(v[0]),
+        f16_to_f64_fallback(v[1]),
+        f16_to_f64_fallback(v[2]),
+        f16_to_f64_fallback(v[3]),
+    ]
+}
+
+#[inline]
+fn f64x4_to_f16x4_fallback(v: &[f64]) -> [u16; 4] {
+    debug_assert!(v.len() >= 4);
+
+    [
+        f64_to_f16_fallback(v[0]),
+        f64_to_f16_fallback(v[1]),
+        f64_to_f16_fallback(v[2]),
+        f64_to_f16_fallback(v[3]),
+    ]
+}
+
+/////////////// x86/x86_64 f16c ////////////////
+#[cfg(all(
+    feature = "use-intrinsics",
+    any(target_arch = "x86", target_arch = "x86_64")
+))]
+mod x86 {
+    use core::{mem::MaybeUninit, ptr};
+
+    #[cfg(target_arch = "x86")]
+    use core::arch::x86::{__m128, __m128i, _mm_cvtph_ps, _mm_cvtps_ph, _MM_FROUND_TO_NEAREST_INT};
+    #[cfg(target_arch = "x86_64")]
+    use core::arch::x86_64::{
+        __m128, __m128i, _mm_cvtph_ps, _mm_cvtps_ph, _MM_FROUND_TO_NEAREST_INT,
+    };
+
+    #[target_feature(enable = "f16c")]
+    #[inline]
+    pub(super) unsafe fn f16_to_f32_x86_f16c(i: u16) -> f32 {
+        let mut vec = MaybeUninit::<__m128i>::zeroed();
+        vec.as_mut_ptr().cast::<u16>().write(i);
+        let retval = _mm_cvtph_ps(vec.assume_init());
+        *(&retval as *const __m128).cast()
+    }
+
+    #[target_feature(enable = "f16c")]
+    #[inline]
+    pub(super) unsafe fn f32_to_f16_x86_f16c(f: f32) -> u16 {
+        let mut vec = MaybeUninit::<__m128>::zeroed();
+        vec.as_mut_ptr().cast::<f32>().write(f);
+        let retval = _mm_cvtps_ph(vec.assume_init(), _MM_FROUND_TO_NEAREST_INT);
+        *(&retval as *const __m128i).cast()
+    }
+
+    #[target_feature(enable = "f16c")]
+    #[inline]
+    pub(super) unsafe fn f16x4_to_f32x4_x86_f16c(v: &[u16]) -> [f32; 4] {
+        debug_assert!(v.len() >= 4);
+
+        let mut vec = MaybeUninit::<__m128i>::zeroed();
+        ptr::copy_nonoverlapping(v.as_ptr(), vec.as_mut_ptr().cast(), 4);
+        let retval = _mm_cvtph_ps(vec.assume_init());
+        *(&retval as *const __m128).cast()
+    }
+
+    #[target_feature(enable = "f16c")]
+    #[inline]
+    pub(super) unsafe fn f32x4_to_f16x4_x86_f16c(v: &[f32]) -> [u16; 4] {
+        debug_assert!(v.len() >= 4);
+
+        let mut vec = MaybeUninit::<__m128>::uninit();
+        ptr::copy_nonoverlapping(v.as_ptr(), vec.as_mut_ptr().cast(), 4);
+        let retval = _mm_cvtps_ph(vec.assume_init(), _MM_FROUND_TO_NEAREST_INT);
+        *(&retval as *const __m128i).cast()
+    }
+
+    #[target_feature(enable = "f16c")]
+    #[inline]
+    pub(super) unsafe fn f16x4_to_f64x4_x86_f16c(v: &[u16]) -> [f64; 4] {
+        debug_assert!(v.len() >= 4);
+
+        let mut vec = MaybeUninit::<__m128i>::zeroed();
+        ptr::copy_nonoverlapping(v.as_ptr(), vec.as_mut_ptr().cast(), 4);
+        let retval = _mm_cvtph_ps(vec.assume_init());
+        let array = *(&retval as *const __m128).cast::<[f32; 4]>();
+        // Let compiler vectorize this regular cast for now.
+        // TODO: investigate auto-detecting sse2/avx convert features
+        [
+            array[0] as f64,
+            array[1] as f64,
+            array[2] as f64,
+            array[3] as f64,
+        ]
+    }
+
+    #[target_feature(enable = "f16c")]
+    #[inline]
+    pub(super) unsafe fn f64x4_to_f16x4_x86_f16c(v: &[f64]) -> [u16; 4] {
+        debug_assert!(v.len() >= 4);
+
+        // Let compiler vectorize this regular cast for now.
+        // TODO: investigate auto-detecting sse2/avx convert features
+        let v = [v[0] as f32, v[1] as f32, v[2] as f32, v[3] as f32];
+
+        let mut vec = MaybeUninit::<__m128>::uninit();
+        ptr::copy_nonoverlapping(v.as_ptr(), vec.as_mut_ptr().cast(), 4);
+        let retval = _mm_cvtps_ph(vec.assume_init(), _MM_FROUND_TO_NEAREST_INT);
+        *(&retval as *const __m128i).cast()
+    }
+}