Hint IO in the SDK

Cargo.toml

@@ -2,13 +2,14 @@
 exclude = ["guest"]
 members = [
   "ceno_emul",
+  "ceno_host",
+  "ceno_zkvm",
   "examples-builder",
   "mpcs",
   "multilinear_extensions",
+  "poseidon",
   "sumcheck",
   "transcript",
-  "ceno_zkvm",
-  "poseidon",
 ]
 resolver = "2"
 
@@ -22,6 +23,7 @@ repository = "https://github.com/scroll-tech/ceno"
 version = "0.1.0"
 
 [workspace.dependencies]
+anyhow = { version = "1.0", default-features = false }
 ark-std = "0.4"
 cfg-if = "1.0"
 criterion = { version = "0.5", features = ["html_reports"] }

ceno_emul/Cargo.toml

@@ -10,7 +10,7 @@ repository.workspace = true
 version.workspace = true
 
 [dependencies]
-anyhow = { version = "1.0", default-features = false }
+anyhow.workspace = true
 elf = "0.7"
 itertools.workspace = true
 num-derive.workspace = true
@@ -20,9 +20,6 @@ strum.workspace = true
 strum_macros.workspace = true
 tracing.workspace = true
 
-[dev-dependencies]
-ceno-examples = { path = "../examples-builder" }
-
 [features]
 default = ["forbid_overflow"]
 forbid_overflow = []

ceno_emul/src/addr.rs

@@ -16,6 +16,7 @@
 
 use std::{
     fmt,
+    iter::Step,
     ops::{self, Range},
 };
 
@@ -106,6 +107,18 @@ impl WordAddr {
     }
 }
 
+impl Step for WordAddr {
+    fn steps_between(start: &Self, end: &Self) -> (usize, Option<usize>) {
+        u32::steps_between(&start.0, &end.0)
+    }
+    fn forward_checked(start: Self, count: usize) -> Option<Self> {
+        u32::forward_checked(start.0, count).map(Self)
+    }
+    fn backward_checked(start: Self, count: usize) -> Option<Self> {
+        u32::backward_checked(start.0, count).map(Self)
+    }
+}
+
 impl fmt::Debug for ByteAddr {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "0x{:08x}", self.0)

ceno_emul/src/host_utils.rs

@@ -0,0 +1,32 @@
+use std::iter::from_fn;
+
+use crate::{ByteAddr, EmuContext, VMState, WordAddr};
+
+const WORD_SIZE: usize = 4;
+const INFO_OUT_ADDR: WordAddr = ByteAddr(0xC000_0000).waddr();
+
+pub fn read_all_messages(state: &VMState) -> Vec<String> {
+    let mut offset: WordAddr = WordAddr::from(0);
+    from_fn(move || match read_message(state, offset) {
+        out if out.is_empty() => None,
+        out => {
+            offset += out.len().div_ceil(WORD_SIZE) as u32 + 1;
+            Some(out)
+        }
+    })
+    .collect()
+}
+
+fn read_message(state: &VMState, offset: WordAddr) -> String {
+    let out_addr = INFO_OUT_ADDR + offset;
+    let byte_len = state.peek_memory(out_addr) as usize;
+
+    String::from_utf8_lossy(
+        &(out_addr + 1_usize..)
+            .map(|memory| state.peek_memory(memory))
+            .flat_map(u32::to_le_bytes)
+            .take(byte_len)
+            .collect::<Vec<_>>(),
+    )
+    .to_string()
+}

ceno_emul/src/lib.rs

@@ -1,4 +1,5 @@
 #![deny(clippy::cargo)]
+#![feature(step_trait)]
 mod addr;
 pub use addr::*;
 
@@ -20,3 +21,4 @@ mod elf;
 pub use elf::Program;
 
 pub mod disassemble;
+pub mod host_utils;

ceno_host/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+categories.workspace = true
+description = "Support for the host port of a Ceno application"
+edition.workspace = true
+keywords.workspace = true
+license.workspace = true
+name = "ceno_host"
+readme.workspace = true
+repository.workspace = true
+version.workspace = true
+
+[dependencies]
+anyhow.workspace = true
+ceno_emul = { path = "../ceno_emul" }
+itertools.workspace = true
+rkyv = { version = "0.8.9", default-features = false, features = ["alloc", "bytecheck"] }
+
+[dev-dependencies]
+ceno-examples = { path = "../examples-builder" }
+rand.workspace = true