Add get_env MWE (#24)

* Add get_env mwe

* Add output_ptr

cairo_programs/get_env.cairo

@@ -0,0 +1,70 @@
+%builtins output
+
+// Represents an integer in the range [0, 2^256).
+struct Uint256 {
+    // The low 128 bits of the value.
+    low: felt,
+    // The high 128 bits of the value.
+    high: felt,
+}
+
+// @notice Store all environment data relevant to the current execution context.
+// @param origin The origin of the transaction.
+// @param gas_price The gas price for the call.
+// @param chain_id The chain id of the current block.
+// @param prev_randao The previous RANDAO value.
+// @param block_number The block number of the current block.
+// @param block_gas_limit The gas limit for the current block.
+// @param block_timestamp The timestamp of the current block.
+// @param coinbase The address of the miner of the current block.
+// @param base_fee The basefee of the current block.
+struct Environment {
+    origin: felt,
+    gas_price: felt,
+    chain_id: felt,
+    prev_randao: Uint256,
+    block_number: felt,
+    block_gas_limit: felt,
+    block_timestamp: felt,
+    coinbase: felt,
+    base_fee: felt,
+}
+
+// @notice Populate an Environment with hint
+func get_env() -> Environment* {
+    tempvar env = cast(nondet %{ segments.add() %}, Environment*);
+
+    // The hint should populate env.
+    %{
+        ids.env.origin=1
+        ids.env.gas_price=2
+        ids.env.chain_id=3
+        ids.env.prev_randao.low=4
+        ids.env.prev_randao.high=4
+        ids.env.block_number=5
+        ids.env.block_gas_limit=6
+        ids.env.block_timestamp=7
+        ids.env.coinbase=8
+        ids.env.base_fee=9
+    %}
+
+    return env;
+}
+
+func main{output_ptr: felt*}() {
+    let env = get_env();
+
+    assert [output_ptr] = env.origin;
+    assert [output_ptr + 1] = env.gas_price;
+    assert [output_ptr + 2] = env.chain_id;
+    assert [output_ptr + 3] = env.prev_randao.low;
+    assert [output_ptr + 4] = env.prev_randao.high;
+    assert [output_ptr + 5] = env.block_number;
+    assert [output_ptr + 6] = env.block_gas_limit;
+    assert [output_ptr + 7] = env.block_timestamp;
+    assert [output_ptr + 8] = env.coinbase;
+    assert [output_ptr + 9] = env.base_fee;
+    let output_ptr = output_ptr + 10;
+
+    return ();
+}