diff --git a/frontend/cmd/assemble.c b/frontend/cmd/assemble.c
index 9eab1e4..db30705 100644
--- a/frontend/cmd/assemble.c
+++ b/frontend/cmd/assemble.c
@@ -1,15 +1,95 @@
+#include "../debug.h"
 #include "cmd.h"
 
 #include <blue/cmd.h>
+#include <blue/term.h>
+#include <errno.h>
+#include <ivy/file.h>
+#include <ivy/asm/lex.h>
+#include <stdio.h>
+
+enum {
+	ARG_SOURCE_FILE,
+};
+
+static int assemble_file(const char *path)
+{
+	FILE *fp = fopen(path, "r");
+	if (!fp) {
+		b_err("cannot open source file '%s'", path);
+		b_i("reason: %s", strerror(errno));
+		return -1;
+	}
+
+	struct ivy_file *src = ivy_file_from_fp(fp);
+	struct ivy_asm_lexer *lex;
+	if (ivy_asm_lexer_create(&lex) != IVY_OK) {
+		b_err("failed to initialise Ivy assembly lexer");
+		ivy_file_close(src);
+		return -1;
+	}
+
+	ivy_asm_lexer_set_source(lex, &src->f_base);
+	enum ivy_status status = IVY_OK;
+
+	while (true) {
+		struct ivy_asm_token *tok = ivy_asm_lexer_read(lex);
+		status = ivy_asm_lexer_get_status(lex);
+		if (status == IVY_ERR_EOF) {
+			break;
+		}
+
+		if (status != IVY_OK) {
+			b_err("failed to parse '%s'", path);
+			b_i("reason: lex error (%s)",
+			    ivy_status_to_string(ivy_asm_lexer_get_status(lex)));
+			break;
+		}
+
+		print_asm_lex_token(tok);
+	}
+
+	int r = (status == IVY_OK || status == IVY_ERR_EOF) ? 0 : -1;
+	ivy_file_close(src);
+	ivy_asm_lexer_destroy(lex);
+	return r;
+}
+
+static int assemble(const b_command *cmd, const b_arglist *args, const b_array *_)
+{
+	b_arglist_iterator it;
+	b_arglist_foreach_filtered(&it, args, B_COMMAND_INVALID_ID, ARG_SOURCE_FILE)
+	{
+		b_arglist_value *path = it.value;
+		if (path->val_type != B_COMMAND_ARG_STRING) {
+			continue;
+		}
+
+		printf("%s\n", path->val_str);
+		int r = assemble_file(path->val_str);
+		if (r != 0) {
+			return r;
+		}
+	}
+
+	return 0;
+}
 
 B_COMMAND(CMD_ASSEMBLE, CMD_ROOT)
 {
 	B_COMMAND_NAME("assemble");
 	B_COMMAND_SHORT_NAME('A');
 	B_COMMAND_DESC(
-		"assemble one or more Ivy assembly source files into Ivy "
-	        "object files.");
+		"assemble one or more Ivy assembly source files into Ivy object files.");
 	B_COMMAND_FLAGS(B_COMMAND_SHOW_HELP_BY_DEFAULT);
+	B_COMMAND_FUNCTION(assemble);
+
+	B_COMMAND_ARG(ARG_SOURCE_FILE)
+	{
+		B_ARG_NAME("source file");
+		B_ARG_DESC("the .iasm assembly files to compile.");
+		B_ARG_NR_VALUES(B_ARG_1_OR_MORE_VALUES);
+	}
 
 	B_COMMAND_HELP_OPTION();
 }