2 files changed, 99 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b980033
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.o
+*.use
diff --git a/asm.myr b/asm.myr
new file mode 100644
index 0000000..f8689d5
--- /dev/null
+++ b/asm.myr
@@ -0,0 +1,97 @@
+use bio
+use std
+
+const readline = {line
+        var cmt = std.strfind(line, ";")
+
+        match cmt
+        | `std.Some (pos): line = line[:pos]
+        | `std.None:
+        ;;
+
+        var parts = std.strtok(line)
+        if std.isspace((line[0] : char))
+                -> (`std.None, parts)
+        else
+                -> (`std.Some(parts[0]), parts[1:])
+        ;;
+}
+
+const upcase = {s
+        var i
+        var buf = std.mksb()
+        for i = 0; i < s.len; i++
+                std.sbputc(buf, std.toupper((s[i] : char)))
+        ;;
+        -> std.sbfin(buf)
+}
+
+const parsehex = {s
+        if s[0] == ('#' : byte)
+                -> std.intparsebase((s[1:] : byte[:]), 16)
+        else
+                -> `std.None
+        ;;
+}
+
+const emitinstr = {p
+        var b
+        var mark = `std.None
+
+        if p.len < 1
+                -> `std.Ok([][:], mark)
+        ;;
+
+        match upcase(p[0])
+        | "CLS":
+                b = [0x00, 0xe0][:]
+        | "SYS":
+                if p.len < 2
+                        -> `std.Err("SYS missing subroutine address")
+                ;;
+                match parsehex(p[1])
+                | `std.Some(n): b = [0x20 | (n & 0x0f00), (n & 0xff)][:]
+                | `std.None: b = [0x2f, 0xff][:]
+                        mark = `std.Some(p[1])
+                ;;
+        | _:
+                -> `std.Err("unrecognized instruction")
+        ;;
+
+        -> `std.Ok((b, mark))
+}
+
+const main = {
+        var fd = bio.mkfile(std.In, bio.Rd)
+        var src = bio.byline(fd)
+        var lc = 0
+
+        var offset = 0
+        var queue = [][:]
+        var buf = [][:]
+        var labels = std.mkht()
+        var res
+
+        for line : src ;
+                match readline(line)
+                | (`std.None, i): res = emitinstr(i)
+                | (`std.Some (label), i): res = emitinstr(i)
+                        std.htput(labels, label, offset)
+                ;;
+
+                match res
+                | `std.Err(msg): std.die(std.fmt("{} at {}", msg, lc))
+                | `std.Ok((bytes, marker)): buf = std.sljoin(&buf, bytes)
+                        offset += bytes.len
+                        match marker
+                        | `std.Some(label): queue = std.slpush(&queue, label)
+                        | `std.None:
+                        ;;
+                ;;
+
+                lc++
+        ;;
+        std.put("{}", buf)
+
+        bio.free(fd)
+}