sse2 stable impl

src/serialize/writer/json.rs

@@ -604,7 +604,7 @@ where
     unsafe {
         reserve_str!(writer, value);
 
-        let written = format_escaped_str_impl_generic_128(
+        let written = format_escaped_str_impl_sse2_128(
             writer.as_mut_buffer_ptr(),
             value.as_bytes().as_ptr(),
             value.len(),
@@ -631,7 +631,7 @@ where
             );
             writer.set_written(written);
         } else {
-            let written = format_escaped_str_impl_generic_128(
+            let written = format_escaped_str_impl_sse2_128(
                 writer.as_mut_buffer_ptr(),
                 value.as_bytes().as_ptr(),
                 value.len(),
@@ -641,7 +641,7 @@ where
     }
 }
 
-#[cfg(not(feature = "unstable-simd"))]
+#[cfg(all(not(feature = "unstable-simd"), not(target_arch = "x86_64")))]
 #[inline(always)]
 fn format_escaped_str<W>(writer: &mut W, value: &str)
 where
@@ -659,6 +659,25 @@ where
     }
 }
 
+#[cfg(all(not(feature = "unstable-simd"), target_arch = "x86_64"))]
+#[inline(always)]
+fn format_escaped_str<W>(writer: &mut W, value: &str)
+where
+    W: ?Sized + io::Write + WriteExt,
+{
+    unsafe {
+        reserve_str!(writer, value);
+
+        let written = format_escaped_str_impl_sse2_128(
+            writer.as_mut_buffer_ptr(),
+            value.as_bytes().as_ptr(),
+            value.len(),
+        );
+
+        writer.set_written(written);
+    }
+}
+
 #[inline]
 pub fn to_writer<W, T>(writer: W, value: &T) -> Result<()>
 where

src/serialize/writer/str/mod.rs

@@ -5,18 +5,25 @@ mod escape;
 #[macro_use]
 mod scalar;
 
+#[cfg(target_arch = "x86_64")]
+mod sse2;
+
 #[cfg(all(feature = "unstable-simd", target_arch = "x86_64", feature = "avx512"))]
 mod avx512;
 
 #[cfg(feature = "unstable-simd")]
 mod generic;
 
-#[cfg(all(feature = "unstable-simd", target_arch = "x86_64", feature = "avx512"))]
-pub use avx512::format_escaped_str_impl_512vl;
+#[cfg(not(feature = "unstable-simd"))]
+pub use scalar::format_escaped_str_scalar;
 
 #[allow(unused_imports)]
 #[cfg(feature = "unstable-simd")]
 pub use generic::format_escaped_str_impl_generic_128;
 
-#[cfg(not(feature = "unstable-simd"))]
-pub use scalar::format_escaped_str_scalar;
+#[cfg(all(feature = "unstable-simd", target_arch = "x86_64", feature = "avx512"))]
+pub use avx512::format_escaped_str_impl_512vl;
+
+#[allow(unused_imports)]
+#[cfg(target_arch = "x86_64")]
+pub use sse2::format_escaped_str_impl_sse2_128;

src/serialize/writer/str/sse2.rs

@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: Apache-2.0
+
+use super::escape::{NEED_ESCAPED, QUOTE_TAB};
+
+use core::mem::transmute;
+
+use core::arch::x86_64::{
+    __m128i, _mm_cmpeq_epi8, _mm_loadu_si128, _mm_movemask_epi8, _mm_or_si128, _mm_set1_epi8,
+    _mm_setzero_si128, _mm_storeu_si128, _mm_subs_epu8,
+};
+
+macro_rules! splat_mm128 {
+    ($val:expr) => {
+        _mm_set1_epi8(transmute::<u8, i8>($val))
+    };
+}
+
+macro_rules! impl_format_simd_sse2_128 {
+    ($dst:expr, $src:expr, $value_len:expr) => {
+        let last_stride_src = $src.add($value_len).sub(STRIDE);
+        let mut nb: usize = $value_len;
+
+        assume!($value_len >= STRIDE);
+
+        let blash = splat_mm128!(b'\\');
+        let quote = splat_mm128!(b'"');
+        let x20 = splat_mm128!(31);
+        let v0 = _mm_setzero_si128();
+
+        unsafe {
+            while nb >= STRIDE {
+                let str_vec = _mm_loadu_si128($src as *const __m128i);
+
+                let mask = _mm_movemask_epi8(_mm_or_si128(
+                    _mm_or_si128(
+                        _mm_cmpeq_epi8(str_vec, blash),
+                        _mm_cmpeq_epi8(str_vec, quote),
+                    ),
+                    _mm_cmpeq_epi8(_mm_subs_epu8(str_vec, x20), v0),
+                )) as u32;
+
+                _mm_storeu_si128($dst as *mut __m128i, str_vec);
+
+                if unlikely!(mask > 0) {
+                    let cn = trailing_zeros!(mask) as usize;
+                    nb -= cn;
+                    $dst = $dst.add(cn);
+                    $src = $src.add(cn);
+                    nb -= 1;
+                    let escape = QUOTE_TAB[*($src) as usize];
+                    write_escape!(escape, $dst);
+                    $dst = $dst.add(escape.1 as usize);
+                    $src = $src.add(1);
+                } else {
+                    nb -= STRIDE;
+                    $dst = $dst.add(STRIDE);
+                    $src = $src.add(STRIDE);
+                }
+            }
+
+            if nb > 0 {
+                let mut scratch: [u8; 32] = [b'a'; 32];
+                let mut str_vec = _mm_loadu_si128(last_stride_src as *const __m128i);
+                _mm_storeu_si128(scratch.as_mut_ptr() as *mut __m128i, str_vec);
+
+                let mut scratch_ptr = scratch.as_mut_ptr().add(16 - nb);
+                str_vec = _mm_loadu_si128(scratch_ptr as *const __m128i);
+
+                let mut mask = _mm_movemask_epi8(_mm_or_si128(
+                    _mm_or_si128(
+                        _mm_cmpeq_epi8(str_vec, blash),
+                        _mm_cmpeq_epi8(str_vec, quote),
+                    ),
+                    _mm_cmpeq_epi8(_mm_subs_epu8(str_vec, x20), v0),
+                )) as u32;
+
+                while nb > 0 {
+                    _mm_storeu_si128($dst as *mut __m128i, str_vec);
+
+                    if unlikely!(mask > 0) {
+                        let cn = trailing_zeros!(mask) as usize;
+                        nb -= cn;
+                        $dst = $dst.add(cn);
+                        scratch_ptr = scratch_ptr.add(cn);
+                        nb -= 1;
+                        mask >>= cn + 1;
+                        let escape = QUOTE_TAB[*(scratch_ptr) as usize];
+                        write_escape!(escape, $dst);
+                        $dst = $dst.add(escape.1 as usize);
+                        scratch_ptr = scratch_ptr.add(1);
+                        str_vec = _mm_loadu_si128(scratch_ptr as *const __m128i);
+                    } else {
+                        $dst = $dst.add(nb);
+                        break;
+                    }
+                }
+            }
+        }
+    };
+}
+
+#[allow(dead_code)]
+#[inline(never)]
+pub unsafe fn format_escaped_str_impl_sse2_128(
+    odst: *mut u8,
+    value_ptr: *const u8,
+    value_len: usize,
+) -> usize {
+    const STRIDE: usize = 16;
+
+    let mut dst = odst;
+    let mut src = value_ptr;
+
+    core::ptr::write(dst, b'"');
+    dst = dst.add(1);
+
+    if value_len < STRIDE {
+        impl_format_scalar!(dst, src, value_len)
+    } else {
+        impl_format_simd_sse2_128!(dst, src, value_len);
+    }
+
+    core::ptr::write(dst, b'"');
+    dst = dst.add(1);
+
+    dst as usize - odst as usize
+}