oasm: Add table to keep track of labels

Implement a hash table used to store a maximum of 128 labels.
This commit adds functions such as label_enter() to add labels
to the table, label_lookup() to lookup labels as well as various
utility functions used internally by the assembler.

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 55 insertions, 0 deletions

diff --git a/usr.bin/oasm/include/oasm/label.h b/usr.bin/oasm/include/oasm/label.h
new file mode 100644
index 0000000..8acb369
--- /dev/null
+++ b/usr.bin/oasm/include/oasm/label.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _OASM_LABEL_H_
+#define _OASM_LABEL_H_
+
+#include <sys/types.h>
+#include <sys/queue.h>
+
+#define MAX_LABELS 128
+
+/*
+ * Represents a label
+ *
+ * @name: Label name (e.g., _start)
+ * @ip: Address at which label code starts
+ */
+struct oasm_label {
+    char *name;
+    uintptr_t ip;
+    TAILQ_ENTRY(oasm_label) link;
+    TAILQ_HEAD(, oasm_label) buckets;
+};
+
+void labels_destroy(void);
+int label_enter(const char *name, uintptr_t ip);
+struct oasm_label *label_lookup(const char *name);
+
+#endif  /* !_OASM_LABEL_H_ */