get rid of loops in impl functions

BLAKE3-team · Jul 19, 2023 · e9643f4 · e9643f4
1 parent e56c6a8
commit e9643f4
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Showing 2 changed files with 52 additions and 38 deletions.
diff --git a/rust/guts/src/avx512.rs b/rust/guts/src/avx512.rs
@@ -122,16 +122,15 @@ unsafe extern "C" fn xof(
     block: *const BlockBytes,
     block_len: u32,
     cv: *const CVBytes,
-    mut counter: u64,
+    counter: u64,
     flags: u32,
-    mut out: *mut u8,
-    mut out_len: usize,
+    out: *mut u8,
+    out_len: usize,
 ) {
-    while out_len >= 16 * BLOCK_LEN {
+    debug_assert!(out_len <= 16 * BLOCK_LEN);
+    if out_len == 16 * BLOCK_LEN {
         blake3_guts_avx512_xof_16_exact(block, block_len, cv, counter, flags, out);
-        counter += 16;
-        out = out.add(16 * BLOCK_LEN);
-        out_len -= 16 * BLOCK_LEN;
+        return;
     }
     crate::xof_using_compress_xof(
         blake3_guts_avx512_compress_xof,
@@ -149,16 +148,15 @@ unsafe extern "C" fn xof_xor(
     block: *const BlockBytes,
     block_len: u32,
     cv: *const CVBytes,
-    mut counter: u64,
+    counter: u64,
     flags: u32,
-    mut out: *mut u8,
-    mut out_len: usize,
+    out: *mut u8,
+    out_len: usize,
 ) {
-    while out_len >= 16 * BLOCK_LEN {
+    debug_assert!(out_len <= 16 * BLOCK_LEN);
+    if out_len == 16 * BLOCK_LEN {
         blake3_guts_avx512_xof_xor_16_exact(block, block_len, cv, counter, flags, out);
-        counter += 16;
-        out = out.add(16 * BLOCK_LEN);
-        out_len -= 16 * BLOCK_LEN;
+        return;
     }
     crate::xof_xor_using_compress_xof(
         blake3_guts_avx512_compress_xof,

diff --git a/rust/guts/src/lib.rs b/rust/guts/src/lib.rs
@@ -284,20 +284,27 @@ impl Implementation {
         block: &BlockBytes,
         block_len: u32,
         cv: &CVBytes,
-        counter: u64,
+        mut counter: u64,
         flags: u32,
-        out: &mut [u8],
+        mut out: &mut [u8],
     ) {
-        unsafe {
-            self.xof_fn()(
-                block,
-                block_len,
-                cv,
-                counter,
-                flags | ROOT,
-                out.as_mut_ptr(),
-                out.len(),
-            );
+        let degree = self.degree();
+        let simd_len = degree * BLOCK_LEN;
+        while !out.is_empty() {
+            let take = cmp::min(simd_len, out.len());
+            unsafe {
+                self.xof_fn()(
+                    block,
+                    block_len,
+                    cv,
+                    counter,
+                    flags | ROOT,
+                    out.as_mut_ptr(),
+                    take,
+                );
+            }
+            out = &mut out[take..];
+            counter += degree as u64;
         }
     }
 
@@ -312,20 +319,27 @@ impl Implementation {
         block: &BlockBytes,
         block_len: u32,
         cv: &CVBytes,
-        counter: u64,
+        mut counter: u64,
         flags: u32,
-        out: &mut [u8],
+        mut out: &mut [u8],
     ) {
-        unsafe {
-            self.xof_xor_fn()(
-                block,
-                block_len,
-                cv,
-                counter,
-                flags | ROOT,
-                out.as_mut_ptr(),
-                out.len(),
-            );
+        let degree = self.degree();
+        let simd_len = degree * BLOCK_LEN;
+        while !out.is_empty() {
+            let take = cmp::min(simd_len, out.len());
+            unsafe {
+                self.xof_xor_fn()(
+                    block,
+                    block_len,
+                    cv,
+                    counter,
+                    flags | ROOT,
+                    out.as_mut_ptr(),
+                    take,
+                );
+            }
+            out = &mut out[take..];
+            counter += degree as u64;
         }
     }
 
@@ -608,6 +622,7 @@ unsafe fn xof_using_compress_xof(
     mut out: *mut u8,
     mut out_len: usize,
 ) {
+    debug_assert!(out_len <= MAX_SIMD_DEGREE * BLOCK_LEN);
     while out_len > 0 {
         let mut block_output = [0u8; 64];
         compress_xof(block, block_len, cv, counter, flags, &mut block_output);
@@ -630,6 +645,7 @@ unsafe fn xof_xor_using_compress_xof(
     mut out: *mut u8,
     mut out_len: usize,
 ) {
+    debug_assert!(out_len <= MAX_SIMD_DEGREE * BLOCK_LEN);
     while out_len > 0 {
         let mut block_output = [0u8; 64];
         compress_xof(block, block_len, cv, counter, flags, &mut block_output);