Test/ef io edge cases

executor/programs/rust/ef_io_demo/.cargo/config.toml

@@ -0,0 +1,5 @@
+[target.riscv64im-lambda-vm-elf]
+rustflags = [
+  "--cfg", "getrandom_backend=\"custom\"",
+  "-C", "passes=lower-atomic"
+]

executor/programs/rust/ef_io_demo/Cargo.toml

@@ -0,0 +1,9 @@
+[workspace]
+
+[package]
+name = "ef_io_demo"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+lambda-vm-syscalls = { path = "../../../../syscalls" }

executor/programs/rust/ef_io_demo/src/main.rs

@@ -0,0 +1,22 @@
+// Demo guest exercising the EF zkVM IO interface (`read_input` / `write_output`).
+//
+// Reads the private input via the EF zero-copy `read_input` shim, then emits it
+// back as the public output in TWO `write_output` calls (split in halves) to
+// exercise the multi-call concatenation requirement of the EF spec.
+use lambda_vm_syscalls as syscalls;
+
+pub fn main() {
+    let mut buf_ptr: *const u8 = core::ptr::null();
+    let mut buf_size: usize = 0;
+    unsafe {
+        syscalls::ef_io::read_input(&mut buf_ptr, &mut buf_size);
+    }
+
+    if buf_size > 0 {
+        let half = buf_size / 2;
+        unsafe {
+            syscalls::ef_io::write_output(buf_ptr, half);
+            syscalls::ef_io::write_output(buf_ptr.add(half), buf_size - half);
+        }
+    }
+}

executor/programs/rust/ef_io_multi_write/.cargo/config.toml

@@ -0,0 +1,5 @@
+[target.riscv64im-lambda-vm-elf]
+rustflags = [
+  "--cfg", "getrandom_backend=\"custom\"",
+  "-C", "passes=lower-atomic"
+]

executor/programs/rust/ef_io_multi_write/Cargo.toml

@@ -0,0 +1,9 @@
+[workspace]
+
+[package]
+name = "ef_io_multi_write"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+lambda-vm-syscalls = { path = "../../../../syscalls" }