1 files changed, 40 insertions, 0 deletions
diff --git a/apps/arith.mu b/apps/arith.mu
new file mode 100644
index 00000000..e5d1be18
--- /dev/null
+++ b/apps/arith.mu
@@ -0,0 +1,40 @@
+fn main args: (addr array (addr array byte)) -> exit-status/ebx: int {
+  # var input/esi: (addr array byte) = args[1] {{{
+  var input/esi: (addr array byte) <- copy 0
+  {
+    var args-in-reg/eax: (addr array (addr array byte)) <- copy args
+    var input-in-eax/eax: (addr addr array byte) <- index args-in-reg, 1
+    input <- copy *input-in-eax
+  }
+  # }}}
+  var result/eax: int <- parse-int input
+  exit-status <- copy result  # only LSB makes it out
+}
+
+fn parse-int _in: (addr array byte) -> result/eax: int {
+  var in/esi: (addr array byte) <- copy _in
+  var len/edx: int <- length in
+  var i/ecx: int <- copy 0
+  var out/edi: int <- copy 0
+  {
+    compare i, len
+    break-if->=
+    # out *= 10
+    {
+      var ten/eax: int <- copy 0xa
+      out <- multiply ten
+    }
+    # c = in[i]
+    var c/eax: byte <- copy 0
+    {
+      var tmp/ebx: (addr byte) <- index in, i
+      c <- copy-byte *tmp
+    }
+    #
+    var digit/eax: int <- to-decimal-digit c
+    out <- add digit
+    i <- increment
+    loop
+  }
+  result <- copy out
+}