[WIP] Sve implementation

Cargo.toml

@@ -27,9 +27,11 @@ harness = false
 [features]
 default = ["blake3/default", "std", "winter_crypto/default", "winter_math/default", "winter_utils/default"]
 std = ["blake3/std", "winter_crypto/std", "winter_math/std", "winter_utils/std"]
+sve_backend = []
 
 [dependencies]
 blake3 = { version = "1.3", default-features = false }
+cfg-if = "1.0.0"
 winter_crypto = { version = "0.6", package = "winter-crypto", default-features = false }
 winter_math = { version = "0.6", package = "winter-math", default-features = false }
 winter_utils = { version = "0.6", package = "winter-utils", default-features = false }
@@ -38,3 +40,6 @@ winter_utils = { version = "0.6", package = "winter-utils", default-features = f
 criterion = { version = "0.5", features = ["html_reports"] }
 proptest = "1.1.0"
 rand_utils = { version = "0.6", package = "winter-rand-utils" }
+
+[build-dependencies]
+cc = "1.0.79"

build.rs

@@ -0,0 +1,18 @@
+fn main() {
+    #[cfg(feature = "sve_backend")]
+    compile_sve_backend();
+}
+
+#[cfg(feature = "sve_backend")]
+fn compile_sve_backend() {
+    println!("cargo:rerun-if-changed=sve/src/sve_inv_sbox.c");
+    println!("cargo:rerun-if-changed=sve/src/sve_inv_sbox.h");
+    println!("cargo:rerun-if-changed=sve/src/inv_sbox.h");
+    println!("cargo:rerun-if-changed=sve/src/inv_sbox.h");
+
+    cc::Build::new()
+        .file("sve/src/sve_inv_sbox.c")
+        .file("sve/src/inv_sbox.c")
+        .flag("-march=armv8-a+sve")
+        .compile("sve");
+}

src/hash/rpo/mod.rs

@@ -1,5 +1,7 @@
 use super::{Digest, ElementHasher, Felt, FieldElement, Hasher, StarkField, ONE, ZERO};
 use core::{convert::TryInto, ops::Range};
+#[cfg(feature = "sve_backend")]
+use winter_math::fields::f64::BaseElement;
 
 mod digest;
 pub use digest::RpoDigest;
@@ -10,6 +12,12 @@ use mds_freq::mds_multiply_freq;
 #[cfg(test)]
 mod tests;
 
+#[cfg(feature = "sve_backend")]
+#[link(name = "sve", kind = "static")]
+extern "C" {
+    fn sve_apply_inv_sbox(state: *mut std::ffi::c_ulong);
+}
+
 // CONSTANTS
 // ================================================================================================
 
@@ -351,7 +359,15 @@ impl Rpo256 {
         // apply second half of RPO round
         Self::apply_mds(state);
         Self::add_constants(state, &ARK2[round]);
-        Self::apply_inv_sbox(state);
+        cfg_if::cfg_if! {
+                if #[cfg(feature = "sve_backend")] {
+                unsafe {
+                    sve_apply_inv_sbox(std::mem::transmute::<*mut BaseElement, *mut u64>(state.as_mut_ptr()));
+                }
+            } else {
+                Self::apply_inv_sbox(state);
+            }
+        }
     }
 
     // HELPER FUNCTIONS

src/hash/rpo/tests.rs

@@ -30,14 +30,56 @@ fn test_sbox() {
     assert_eq!(expected, actual);
 }
 
+#[cfg(feature = "sve_backend")]
+#[link(name = "sve", kind = "static")]
+extern "C" {
+    fn apply_inv_sbox_c(state: *mut std::ffi::c_ulong);
+    fn sve_apply_inv_sbox(state: *mut std::ffi::c_ulong);
+}
+
 #[test]
 fn test_inv_sbox() {
-    let state = [Felt::new(rand_value()); STATE_WIDTH];
+    let state: [Felt; STATE_WIDTH] = [
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+        Felt::new(rand_value()),
+    ];
 
     let mut expected = state;
     expected.iter_mut().for_each(|v| *v = v.exp(INV_ALPHA));
-
     let mut actual = state;
+
+    cfg_if::cfg_if! {
+        if #[cfg(feature = "sve_backend")] {
+        let mut actual_c: [u64; STATE_WIDTH] = [0; STATE_WIDTH];
+        for i in 0..STATE_WIDTH {
+            actual_c[i] = actual[i].inner();
+        }
+
+        let mut actual_c_sve: [u64; STATE_WIDTH] = [0; STATE_WIDTH];
+        for i in 0..STATE_WIDTH {
+            actual_c_sve[i] = actual[i].inner();
+        }
+        unsafe {
+            apply_inv_sbox_c(actual_c.as_mut_ptr());
+            sve_apply_inv_sbox(actual_c_sve.as_mut_ptr());
+        }
+
+        let expected_as_u64_vec: Vec<u64> = expected.iter().map(|s| s.inner()).collect();
+        assert_eq!(expected_as_u64_vec, actual_c);
+        assert_eq!(expected_as_u64_vec, actual_c_sve);
+        }
+    }
+
     Rpo256::apply_inv_sbox(&mut actual);
 
     assert_eq!(expected, actual);

sve/.clang-format

@@ -0,0 +1,6 @@
+UseTab: ForIndentation
+IndentWidth: 8
+BreakBeforeBraces: Allman
+AllowShortIfStatementsOnASingleLine: false
+IndentCaseLabels: false
+ColumnLimit: 120

sve/Makefile

@@ -0,0 +1,43 @@
+.PHONY: clean fmt
+
+TARGET=test_sve
+
+CC=cc
+CFLAGS=-std=c99 -march=armv8-a+sve -Wall -Wextra -pedantic -g -O0
+LN_FLAGS=
+
+BUILD_DIR=./build
+SRC_DIR=./src
+
+SOURCE = $(wildcard $(SRC_DIR)/*.c)
+HEADERS = $(wildcard $(SRC_DIR)/*.h)
+OBJECTS = $(patsubst $(SRC_DIR)/%.c, $(BUILD_DIR)/%.o, $(SOURCE))
+
+# Gcc/Clang will create these .d files containing dependencies.
+DEP = $(OBJECTS:%.o=%.d)
+
+default: $(TARGET)
+
+$(TARGET): $(BUILD_DIR)/$(TARGET)
+
+$(BUILD_DIR)/$(TARGET): $(OBJECTS)
+	$(CC) $(CFLAGS) $(LN_FLAGS) $^ -o $@
+
+-include $(DEP)
+
+# The potential dependency on header files is covered
+# by calling `-include $(DEP)`.
+# The -MMD flags additionaly creates a .d file with
+# the same name as the .o file.
+$(BUILD_DIR)/%.o: $(SRC_DIR)/%.c
+	@mkdir -p $(@D)
+	$(CC) $(CFLAGS) -MMD -c $< -o $@
+
+test: $(TARGET)
+	$(BUILD_DIR)/$(TARGET)
+
+clean:
+	rm -rf $(BUILD_DIR)
+
+fmt:
+	clang-format --style=file -i $(SOURCE) $(HEADERS)