Add stdlib: precompiles

stdlib/src/precompiles.sol

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: Apache-2.0
+
+function sha256(bytes memory input) returns (bytes32 ret) {
+  assembly {
+    let success := staticcall(gas(), 2, add(input, 32), mload(input), 0, 32)
+    if iszero(success) { revert(0, 0) }
+    ret := mload(0)
+  }
+}
+
+function ripemd160(bytes memory input) returns (bytes20 ret) {
+  assembly {
+    let success := staticcall(gas(), 3, add(input, 32), mload(input), 0, 32)
+    if iszero(success) { revert(0, 0) }
+    // TODO: check byteorder
+    ret := mload(0)
+  }
+}
+
+function ecrecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) returns (address addr) {
+  assembly {
+    // Prepare input
+    // We are using the free memory pointer.
+    let input := mload(0x40)
+    mstore(input, hash)
+    mstore(add(input, 32), v)
+    mstore(add(input, 64), r)
+    mstore(add(input, 96), s)
+
+    // Prepare output
+    let output := add(input, 128)
+    mstore(output, 0)
+
+    // Call the precompile
+    let ret := staticcall(gas(), 1, input, 128, output, 32)
+    switch ret
+    case 1 { // Success
+      addr := mload(output)
+    }
+    default { // Failure
+      // Need to do anything?
+    }
+  }
+}