Add 128bit Rust BPF test (#4766)

automerge

programs/bpf/rust/128bit/src/lib.rs

@@ -0,0 +1,41 @@
+//! @brief Example Rust-based BPF program tests loop iteration
+
+#![no_std]
+#![allow(unused_attributes)]
+
+extern crate solana_sdk_bpf_utils;
+
+use solana_sdk_bpf_utils::info;
+
+#[no_mangle]
+pub extern "C" fn entrypoint(_input: *mut u8) -> bool {
+    let x: u128 = 1;
+    let y = x.rotate_right(1);
+    assert_eq!(y, 170_141_183_460_469_231_731_687_303_715_884_105_728);
+
+    assert_eq!(
+        u128::max_value(),
+        340_282_366_920_938_463_463_374_607_431_768_211_455
+    );
+
+    let mut z = u128::max_value();
+    z -= 1;
+    assert_eq!(z, 340_282_366_920_938_463_463_374_607_431_768_211_454);
+
+    let x = u64::max_value();
+    assert_eq!(u128::from(x) + u128::from(x), 36_893_488_147_419_103_230);
+
+    let x = solana_bpf_rust_128bit_dep::work(
+        u128::from(u64::max_value()),
+        u128::from(u64::max_value()),
+    );
+    assert_eq!(x.wrapping_shr(64) as u64, 1);
+    assert_eq!(
+        x.wrapping_shl(64).wrapping_shr(64) as u64,
+        0xffff_ffff_ffff_fffe
+    );
+    assert_eq!(x, 0x0001_ffff_ffff_ffff_fffe);
+
+    info!("Success");
+    true
+}