From 65637862923b39237bc860d0aa9c420dda6be4ab Mon Sep 17 00:00:00 2001
From: Lukas Krickl <lukas@krickl.dev>
Date: Wed, 28 Feb 2024 10:45:23 +0100
Subject: [PATCH] Added unnamed labels

Unnamed labels can be declared using just a :.
Unnamed labels ignore redefinition rules and
just get added to the symbol list regardless.
They currently only serve as markers, however in the future they can be
reached using + and - symbols to jump to the next or previous label
respectively.
---
 src/ulas.c      |  17 ++++++++++++-----
 src/ulas.h      |   2 --
 tests/t0.bin    | Bin 215 -> 216 bytes
 tests/t0.s      |   5 +++++
 tests/t0_dasm.s |   1 +
 5 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/src/ulas.c b/src/ulas.c
index a5783c8..917858c 100644
--- a/src/ulas.c
+++ b/src/ulas.c
@@ -265,7 +265,7 @@ int ulas_isname(const char *tok, unsigned long n) {
 }
 
 int ulas_islabelname(const char *tok, unsigned long n) {
-  return tok[n - 1] == ':' && ulas_isname(tok, n - 1);
+  return tok[n - 1] == ':' && (ulas_isname(tok, n - 1) || n == 1);
 }
 
 struct ulas_sym *ulas_symbolresolve(const char *name, int scope, int *rc) {
@@ -311,7 +311,7 @@ int ulas_symbolset(const char *cname, int scope, struct ulas_tok tok,
     ulas.scope++;
   }
 
-  if (!existing) {
+  if (!existing || (name[0] == '\0' && len == 1)) {
     // def new symbol
     struct ulas_sym new_sym = {strndup(name, len), tok, scope, ulas.pass,
                                constant};
@@ -340,7 +340,11 @@ int ulas_symbolout(FILE *dst, struct ulas_sym *s) {
   }
 
   int rc = 0;
-  fprintf(dst, "%s = ", s->name);
+  if (!s->name || s->name[0] == '\0') {
+    fprintf(dst, "<unnamed> = ");
+  } else {
+    fprintf(dst, "%s = ", s->name);
+  }
   switch (s->tok.type) {
   case ULAS_INT:
     fprintf(dst, "0x%x", ulas_valint(&s->tok, &rc));
@@ -1470,7 +1474,8 @@ int ulas_parsecmp(int *i);
 int ulas_parseun(int *i) {
   struct ulas_tok *t = ulas_tokbufget(&ulas.toks, *i);
 
-  if (t && (t->type == '!' || t->type == '-' || t->type == '~' || t->type == '+')) {
+  if (t &&
+      (t->type == '!' || t->type == '-' || t->type == '~' || t->type == '+')) {
     int op = *i;
     *i += 1;
     int right = ulas_parseun(i);
@@ -2336,7 +2341,9 @@ int ulas_asmline(FILE *dst, FILE *src, const char *line, unsigned long n) {
   if (ulas_islabelname(ulas.tok.buf, strlen(ulas.tok.buf))) {
     instr_start = line;
     struct ulas_tok label_tok = {ULAS_INT, {(int)ulas.address}};
-    ulas_symbolset(ulas.tok.buf, -1, label_tok, 1);
+    if (ulas_symbolset(ulas.tok.buf, -1, label_tok, 1) == -1) {
+      return -1;
+    }
     ulas_tok(&ulas.tok, &line, n);
     // is next token empty?
     if (ulas_istokend(&ulas.tok)) {
diff --git a/src/ulas.h b/src/ulas.h
index fe29e7f..8c58880 100644
--- a/src/ulas.h
+++ b/src/ulas.h
@@ -248,7 +248,6 @@ struct ulas_preproc {
   struct ulas_str macrobuf;
 };
 
-
 struct ulas {
   struct ulas_preproc pp;
   char *filename;
@@ -427,7 +426,6 @@ enum ulas_asmdir {
   ULAS_ASMDIR_REP,
 };
 
-
 #define ULAS_INSTRTOKMAX 16
 #define ULAS_INSTRDATMAX 16
 
diff --git a/tests/t0.bin b/tests/t0.bin
index 371ef142ee4dd29c40eb82131274098a23b74568..4f18f9a43542ebf2402d537bcb4dba529ac78012 100644
GIT binary patch
delta 8
Pcmcc4c!P1mb;dFP5g7xJ

delta 6
Ncmcb?c%5;=bpQ%+0~r7S

diff --git a/tests/t0.s b/tests/t0.s
index fe5ffc8..18f76f8 100644
--- a/tests/t0.s
+++ b/tests/t0.s
@@ -155,3 +155,8 @@ nextlevel $2
 #endmacro 
 
 toplevel 5, 6
+
+:
+:
+  halt
+
diff --git a/tests/t0_dasm.s b/tests/t0_dasm.s
index a83a590..0ea1f10 100644
--- a/tests/t0_dasm.s
+++ b/tests/t0_dasm.s
@@ -120,3 +120,4 @@
   dec b
   inc b
 .db 0x6
+.db 0x76
-- 
2.30.2