Merge pull request #87 from kkebo/memcpy-and-memset

Author: kkebo

Package.swift

@@ -24,6 +24,7 @@ let package = Package(
         .executableTarget(
             name: "Kernel",
             dependencies: [
+                "Support",
                 "AsmSupport",
                 .byName(name: "RaspberryPi", condition: .when(traits: ["RASPI"])),
             ],
@@ -37,6 +38,7 @@ let package = Package(
             ],
         ),
         .target(name: "Font", swiftSettings: swiftSettings),
+        .target(name: "Support", swiftSettings: swiftSettings),
         .target(name: "AsmSupport"),
     ],
 )

Sources/Support/memcpy.swift

@@ -0,0 +1,15 @@
+@_silgen_name("memcpy")
+func memcpy(
+    _ dst: UnsafeMutableRawPointer,
+    _ src: UnsafeRawPointer,
+    _ n: Int,
+) -> UnsafeMutableRawPointer {
+    let dst = unsafe dst.bindMemory(to: UInt8.self, capacity: n)
+    var dstSpan = unsafe MutableSpan(_unsafeStart: dst, count: n)
+    let src = unsafe src.bindMemory(to: UInt8.self, capacity: n)
+    let srcSpan = unsafe Span(_unsafeStart: src, count: n)
+    for i in dstSpan.indices {
+        dstSpan[i] = srcSpan[i]
+    }
+    return .init(dst)
+}

Sources/Support/memset.swift

@@ -0,0 +1,13 @@
+@_silgen_name("memset")
+func memset(
+    _ dst: UnsafeMutableRawPointer,
+    _ val: CInt,
+    _ len: Int,
+) -> UnsafeMutableRawPointer {
+    let dst = unsafe dst.bindMemory(to: UInt8.self, capacity: len)
+    var span = unsafe MutableSpan(_unsafeStart: dst, count: len)
+    for i in span.indices {
+        span[i] = UInt8(truncatingIfNeeded: val)
+    }
+    return .init(dst)
+}