cpuid crate refactoring - part 2

cpuid/src/bit_helper.rs

@@ -1,6 +1,8 @@
 // Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
+#![macro_use]
+
 /// Structure representing a range of bits in a number.
 ///
 /// # Example
@@ -86,9 +88,22 @@ impl BitRangeExt<u32> for BitRange {
     }
 }
 
+macro_rules! bit_range {
+    ($msb_index:expr, $lsb_index:expr) => {
+        BitRange {
+            msb_index: $msb_index,
+            lsb_index: $lsb_index,
+        }
+    };
+}
+
 /// Trait containing helper methods for bit operations.
 ///
 pub trait BitHelper {
+    /// Reads the value of the bit at position `pos`
+    ///
+    fn read_bit(&self, pos: u32) -> bool;
+
     /// Changes the value of the bit at position `pos` to `val`
     ///
     fn write_bit(&mut self, pos: u32, val: bool) -> &mut Self;
@@ -144,6 +159,12 @@ pub trait BitHelper {
 }
 
 impl BitHelper for u32 {
+    fn read_bit(&self, pos: u32) -> bool {
+        assert!(pos <= MAX_U32_BIT_INDEX, "Invalid pos");
+
+        (*self & (1 << pos)) > 0
+    }
+
     fn write_bit(&mut self, pos: u32, val: bool) -> &mut Self {
         assert!(pos <= MAX_U32_BIT_INDEX, "Invalid pos");
 
@@ -215,6 +236,22 @@ mod tests {
         assert!(val == 0);
     }
 
+    #[test]
+    #[should_panic]
+    fn test_invalid_read_bit() {
+        // Set bit to 1
+        let val: u32 = 0;
+        val.read_bit(32);
+    }
+
+    #[test]
+    fn test_simple_read_bit() {
+        // Set bit to 1
+        let val: u32 = 0b100000;
+        assert!(val.read_bit(5));
+        assert!(!val.read_bit(4));
+    }
+
     #[test]
     fn test_chained_write_bit() {
         let mut val: u32 = 1 << 12;

cpuid/src/brand_string.rs

@@ -4,7 +4,7 @@
 use std::arch::x86_64::__cpuid as host_cpuid;
 use std::slice;
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone)]
 pub enum Error {
     NotSupported,
     Overflow(String),
@@ -23,6 +23,7 @@ pub enum Reg {
 /// This is achieved by bypassing the `O(n)` indexing, heap allocation, and the unicode checks
 /// done by `std::string::String`.
 ///
+#[derive(Clone)]
 pub struct BrandString {
     /// Flattened buffer, holding an array of 32-bit register values.
     ///

cpuid/src/cpu_leaf.rs

@@ -16,20 +16,11 @@ pub mod leaf_0x1 {
         use bit_helper::BitRange;
 
         // The bit-range containing the (fixed) default APIC ID.
-        pub const APICID_BITRANGE: BitRange = BitRange {
-            msb_index: 31,
-            lsb_index: 24,
-        };
+        pub const APICID_BITRANGE: BitRange = bit_range!(31, 24);
         // The bit-range containing the number of bytes flushed when executing CLFLUSH.
-        pub const CLFLUSH_SIZE_BITRANGE: BitRange = BitRange {
-            msb_index: 15,
-            lsb_index: 8,
-        };
+        pub const CLFLUSH_SIZE_BITRANGE: BitRange = bit_range!(15, 8);
         // The bit-range containing the logical processor count.
-        pub const CPU_COUNT_BITRANGE: BitRange = BitRange {
-            msb_index: 23,
-            lsb_index: 16,
-        };
+        pub const CPU_COUNT_BITRANGE: BitRange = bit_range!(23, 16);
     }
 
     pub mod ecx {
@@ -77,18 +68,9 @@ pub mod leaf_0x4 {
     pub mod eax {
         use bit_helper::BitRange;
 
-        pub const CACHE_LEVEL_BITRANGE: BitRange = BitRange {
-            msb_index: 7,
-            lsb_index: 5,
-        };
-        pub const MAX_ADDR_IDS_SHARING_CACHE_BITRANGE: BitRange = BitRange {
-            msb_index: 25,
-            lsb_index: 14,
-        };
-        pub const MAX_ADDR_IDS_IN_PACKAGE_BITRANGE: BitRange = BitRange {
-            msb_index: 31,
-            lsb_index: 26,
-        };
+        pub const CACHE_LEVEL_BITRANGE: BitRange = bit_range!(7, 5);
+        pub const MAX_CPUS_PER_CORE_BITRANGE: BitRange = bit_range!(25, 14);
+        pub const MAX_CORES_PER_PACKAGE_BITRANGE: BitRange = bit_range!(31, 26);
     }
 }
 
@@ -184,33 +166,21 @@ pub mod leaf_0xb {
 
         // The bit-range containing the number of bits to shift right the APIC ID in order to get
         // the next level APIC ID
-        pub const APICID_BITRANGE: BitRange = BitRange {
-            msb_index: 4,
-            lsb_index: 0,
-        };
+        pub const APICID_BITRANGE: BitRange = bit_range!(4, 0);
     }
 
     pub mod ebx {
         use bit_helper::BitRange;
 
         // The bit-range containing the number of factory-configured logical processors
         // at the current cache level
-        pub const NUM_LOGICAL_PROCESSORS_BITRANGE: BitRange = BitRange {
-            msb_index: 15,
-            lsb_index: 0,
-        };
+        pub const NUM_LOGICAL_PROCESSORS_BITRANGE: BitRange = bit_range!(15, 0);
     }
 
     pub mod ecx {
         use bit_helper::BitRange;
 
-        pub const LEVEL_TYPE_BITRANGE: BitRange = BitRange {
-            msb_index: 15,
-            lsb_index: 8,
-        };
-        pub const LEVEL_NUMBER_BITRANGE: BitRange = BitRange {
-            msb_index: 7,
-            lsb_index: 0,
-        };
+        pub const LEVEL_TYPE_BITRANGE: BitRange = bit_range!(15, 8);
+        pub const LEVEL_NUMBER_BITRANGE: BitRange = bit_range!(7, 0);
     }
 }