diff --git a/scripts/annotate_asm.js b/scripts/annotate_asm.js
new file mode 100644
index 00000000..26e1a260
--- /dev/null
+++ b/scripts/annotate_asm.js
@@ -0,0 +1,103 @@
+const child_process = require("child_process")
+const fs = require("fs")
+
+const sysroot = child_process.execSync("rustc --print sysroot").toString().trim()
+
+function main(sname, filter) {
+    if (!filter) {
+        console.error("please pass filter arg")
+        return
+    }
+
+    const sections = {}
+    const files = []
+    let idx = 0
+    for (const sect of fs.readFileSync(sname, "utf8").split("\n\n")) {
+        idx++
+        let sectId = "sect" + idx
+        let m = /^\t\.type\t(.*),@/m.exec(sect)
+        if (m) {
+            sectId = m[1]
+        }
+
+        let outp = ""
+        for (const line of sect.split("\n")) {
+            if (line.startsWith(".Ltmp") || line.startsWith("\t.cfi_"))
+                continue
+            if (line.startsWith("\t.file\t")) {
+                m = /(\d+)\s+"([^"]+)"\s+"([^"]+)"/.exec(line)
+                if (!m) {
+                    // console.error("Bad file line", line)
+                } else {
+                    const folder = m[2].replace(/^\/rustc\/[^/]+/, sysroot + "/lib/rustlib/src/rust")
+                    files[+m[1]] = folder + "/" + m[3]
+                }
+                continue
+            }
+            outp += line + "\n"
+        }
+
+        sections[sectId] = outp
+    }
+
+    const keys = Object.keys(sections).filter(k => k.includes(filter))
+    if (keys.length > 1) {
+        const max = 50
+        console.error("Multiple sections found for filter", filter, keys.slice(0, max).join("\n"))
+        if (keys.length > max) {
+            console.error("...")
+        }
+        return
+    }
+    if (keys.length === 0) {
+        console.error("No sections found for filter", filter)
+        return
+    }
+
+    const filecontent = []
+
+    function fileLines(id) {
+        if (filecontent[id]) {
+            return filecontent[id]
+        }
+        const lines = fs.readFileSync(files[id], "utf8").split("\n")
+        filecontent[id] = lines
+        return lines
+    }
+
+    let outp = ""
+    const labels = {}
+    for (let line of sections[keys[0]].split("\n")) {
+        if (line.startsWith("\t.loc\t")) {
+            const m = /\t.loc\t(\d+)\s+(\d+)\s+(\d+)/.exec(line)
+            const lineno = +m[2]
+            const lines = fileLines(+m[1])
+            const filename = files[+m[1]]
+            let basename = filename.split("/").pop()
+            if (filename.startsWith(sysroot))
+                basename = "[lib]" + basename
+            // outp += "// file://" + files[+m[1]] + "\n"
+            if (lines[lineno - 1] !== undefined) {
+                const tag = basename + ":" + lineno
+                outp += "// " + tag.padEnd(40, " ") + lines[lineno - 1] + "\n"
+            }
+        } else {
+            const m = /^(\.L\w+):/.exec(line)
+            if (m) {
+                labels[m[1]] = true
+            }
+            const words = line.split(/\s+/)
+            if (words.some(w => labels[w])) {
+                line += " // ===============================================> BACK"
+            }
+            outp += line + "\n"
+        }
+    }
+
+    console.log("Section", keys[0], ":")
+    console.log(outp)
+}
+
+
+const args = process.argv.slice(2)
+main(...args)
diff --git a/scripts/disasm.sh b/scripts/disasm.sh
new file mode 100755
index 00000000..5de31611
--- /dev/null
+++ b/scripts/disasm.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+
+TRG=`rustup show | head -1 | sed -e 's/.*: //'`
+#CRATE=`grep "^name =" Cargo.toml  | head -1 | sed -e 's/.*= "//; s/"//'`
+CRATE=$1
+shift
+RUSTFLAGS="--emit asm" cargo build --release --target $TRG
+TRG_DIR=`cargo metadata --format-version 1 | jq -r '.target_directory'`
+F=`echo $TRG_DIR/$TRG/release/deps/$CRATE-*.s`
+# if $F has more than one file
+if [ `echo $F | wc -w` -gt 1 ]; then
+    echo "More than one file found: $F; removing; try again"
+    rm -f $F
+    exit 1
+fi
+
+mkdir -p tmp
+cp $F tmp/full.s
+HERE=$(dirname $0)
+node $HERE/annotate_asm.js tmp/full.s "$@" | rustfilt -h > tmp/func.s
+ls -l tmp/func.s