From 4c81eacefebc6e53903abc80d211b1c1b0f18c7a Mon Sep 17 00:00:00 2001
From: Kugel Fuhr <98353208+kugelfuhr@users.noreply.github.com>
Date: Fri, 20 Jun 2025 13:00:12 +0200
Subject: [PATCH] Added -d/--debug and -m/--multi-pass switches to the
 disassembler. The latter will make the disassembler run multiple preparation
 passes to find all addresses where labels must be placed. Without -m some
 label addresses are found in the final pass, where the disassembler cannot
 make use of them.

---
 doc/da65.sgml     | 21 ++++++++++++++-
 src/da65/global.c |  2 +-
 src/da65/global.h |  4 ++-
 src/da65/labels.c | 14 ++++++++++
 src/da65/labels.h |  3 +++
 src/da65/main.c   | 68 ++++++++++++++++++++++++++++++++++++++++++++---
 src/da65/output.c | 16 +++++------
 7 files changed, 113 insertions(+), 15 deletions(-)

diff --git a/doc/da65.sgml b/doc/da65.sgml
index dd51a4764..314e552a9 100644
--- a/doc/da65.sgml
+++ b/doc/da65.sgml
@@ -46,14 +46,16 @@ The assembler accepts the following options:
 ---------------------------------------------------------------------------
 Usage: da65 [options] [inputfile]
 Short options:
+  -d                    Debug mode
   -g                    Add debug info to object file
   -h                    Help (this text)
   -i name               Specify an info file
+  -m                    Run multiple passes to resolve labels
   -o name               Name the output file
   -v                    Increase verbosity
   -F                    Add formfeeds to the output
-  -s                    Accept line markers in the info file
   -S addr               Set the start/load address
+  -s                    Accept line markers in the info file
   -V                    Print the disassembler version
 
 Long options:
@@ -61,6 +63,7 @@ Long options:
   --comment-column n    Specify comment start column
   --comments n          Set the comment level for the output
   --cpu type            Set cpu type
+  --debug               Debug mode
   --debug-info          Add debug info to object file
   --formfeeds           Add formfeeds to the output
   --help                Help (this text)
@@ -68,6 +71,7 @@ Long options:
   --info name           Specify an info file
   --label-break n       Add newline if label exceeds length n
   --mnemonic-column n   Specify mnemonic start column
+  --multi-pass          Run multiple passes to resolve labels
   --pagelength n        Set the page length for the listing
   --start-addr addr     Set the start/load address
   --sync-lines          Accept line markers in the info file
@@ -123,6 +127,12 @@ Here is a description of all the command line options:
   </itemize>
 
 
+  <tag><tt>-d, --debug</tt></tag>
+
+  Enables debug mode, something that should not be needed for mere
+  mortals:-)
+
+
   <label id="option--formfeeds">
   <tag><tt>-F, --formfeeds</tt></tag>
 
@@ -179,6 +189,15 @@ Here is a description of all the command line options:
   <tt><ref id="LABELBREAK" name="LABELBREAK"></tt>.
 
 
+  <tag><tt>-m, --multi-pass</tt></tag>
+
+  This option causes the disassembler to run multiple passes over the input
+  binary to find and create all necessary labels. Without this option the
+  disassembler may detect the necessity for a label in the final pass, when
+  output was already partially generated. It will output numerical addresses
+  or program counter relative expressions in this case.
+
+
   <label id="option--mnemonic-column">
   <tag><tt>--mnemonic-column n</tt></tag>
 
diff --git a/src/da65/global.c b/src/da65/global.c
index 7e5cabf54..74f70b6fd 100644
--- a/src/da65/global.c
+++ b/src/da65/global.c
@@ -54,8 +54,8 @@ const char CfgExt[]           = ".cfg"; /* Config file extension */
 /* Flags and other command line stuff */
 unsigned char DebugInfo       = 0;      /* Add debug info to the object file */
 unsigned char FormFeeds       = 0;      /* Add form feeds to the output? */
+unsigned char MultiPass       = 0;      /* Run several passes to resolve labels */
 unsigned char UseHexOffs      = 0;      /* Use hexadecimal label offsets */
-unsigned char PassCount       = 2;      /* How many passed do we do? */
 signed char   NewlineAfterJMP = -1;     /* Add a newline after a JMP insn? */
 signed char   NewlineAfterRTS = -1;     /* Add a newline after a RTS insn? */
 unsigned char HaveStartAddr   = 0;      /* Flag for start address given */
diff --git a/src/da65/global.h b/src/da65/global.h
index 2e558d6a9..8e3fe90ee 100644
--- a/src/da65/global.h
+++ b/src/da65/global.h
@@ -59,8 +59,8 @@ extern const char       CfgExt[];       /* Config file extension */
 /* Flags and other command line stuff */
 extern unsigned char    DebugInfo;      /* Add debug info to the object file */
 extern unsigned char    FormFeeds;      /* Add form feeds to the output? */
+extern unsigned char    MultiPass;      /* Run several passes to resolve labels */
 extern unsigned char    UseHexOffs;     /* Use hexadecimal label offsets */
-extern unsigned char    PassCount;      /* How many passed do we do? */
 extern signed char      NewlineAfterJMP;/* Add a newline after a JMP insn? */
 extern signed char      NewlineAfterRTS;/* Add a newline after a RTS insn? */
 extern unsigned char    HaveStartAddr;  /* Flag for start address given */
@@ -70,6 +70,8 @@ extern long             InputOffs;      /* Offset into input file */
 extern long             InputSize;      /* Number of bytes to read from input */
 
 /* Stuff needed by many routines */
+#define PASS_PREP       1               /* Preparation pass */
+#define PASS_FINAL      2               /* Final pass generating output */
 extern unsigned         Pass;           /* Disassembler pass */
 extern char             Now[128];       /* Current time as string */
 
diff --git a/src/da65/labels.c b/src/da65/labels.c
index 6f6bce3ed..a2c027705 100644
--- a/src/da65/labels.c
+++ b/src/da65/labels.c
@@ -74,6 +74,9 @@ struct Label {
 #define LABEL_HASH_SIZE         4096u   /* Must be power of two */
 static Label* LabelTab[LABEL_HASH_SIZE];
 
+/* Total number of labels */
+static unsigned long LabelCount = 0;
+
 
 
 /*****************************************************************************/
@@ -187,6 +190,9 @@ static void AddLabel (uint32_t Addr, attr_t Attr, const char* Name)
 
     /* Remember the attribute */
     MarkAddr (Addr, Attr);
+
+    /* Count labels */
+    ++LabelCount;
 }
 
 
@@ -538,3 +544,11 @@ void DefOutOfRangeLabels (void)
     /* Free allocated storage */
     DoneCollection (&Labels);
 }
+
+
+
+unsigned long GetLabelCount (void)
+/* Return the total number of labels defined so far */
+{
+    return LabelCount;
+}
diff --git a/src/da65/labels.h b/src/da65/labels.h
index 37f2daeab..923a4bd43 100644
--- a/src/da65/labels.h
+++ b/src/da65/labels.h
@@ -100,6 +100,9 @@ void ForwardLabel (unsigned Offs);
 void DefOutOfRangeLabels (void);
 /* Output any labels that are out of the loaded code range */
 
+unsigned long GetLabelCount (void);
+/* Return the total number of labels defined so far */
+
 
 
 /* End of labels.h */
diff --git a/src/da65/main.c b/src/da65/main.c
index a00bf588a..03dbcaccf 100644
--- a/src/da65/main.c
+++ b/src/da65/main.c
@@ -42,8 +42,10 @@
 
 /* common */
 #include "abend.h"
+#include "check.h"
 #include "cmdline.h"
 #include "cpu.h"
+#include "debugflag.h"
 #include "fname.h"
 #include "print.h"
 #include "version.h"
@@ -79,9 +81,11 @@ static void Usage (void)
 {
     printf ("Usage: %s [options] [inputfile]\n"
             "Short options:\n"
+            "  -d\t\t\tDebug mode\n"
             "  -g\t\t\tAdd debug info to object file\n"
             "  -h\t\t\tHelp (this text)\n"
             "  -i name\t\tSpecify an info file\n"
+            "  -m\t\t\tRun multiple passes to resolve labels\n"
             "  -o name\t\tName the output file\n"
             "  -v\t\t\tIncrease verbosity\n"
             "  -F\t\t\tAdd formfeeds to the output\n"
@@ -94,6 +98,7 @@ static void Usage (void)
             "  --comment-column n\tSpecify comment start column\n"
             "  --comments n\t\tSet the comment level for the output\n"
             "  --cpu type\t\tSet cpu type\n"
+            "  --debug\t\tDebug mode\n"
             "  --debug-info\t\tAdd debug info to object file\n"
             "  --formfeeds\t\tAdd formfeeds to the output\n"
             "  --help\t\tHelp (this text)\n"
@@ -101,6 +106,7 @@ static void Usage (void)
             "  --info name\t\tSpecify an info file\n"
             "  --label-break n\tAdd newline if label exceeds length n\n"
             "  --mnemonic-column n\tSpecify mnemonic start column\n"
+            "  --multi-pass\t\tRun multiple passes to resolve labels\n"
             "  --pagelength n\tSet the page length for the listing\n"
             "  --start-addr addr\tSet the start/load address\n"
             "  --sync-lines\t\tAccept line markers in the info file\n"
@@ -223,6 +229,15 @@ static void OptCPU (const char* Opt attribute ((unused)), const char* Arg)
 
 
 
+static void OptDebug (const char* Opt attribute ((unused)),
+                      const char* Arg attribute ((unused)))
+/* Disassembler debug mode */
+{
+    ++Debug;
+}
+
+
+
 static void OptDebugInfo (const char* Opt attribute ((unused)),
                           const char* Arg attribute ((unused)))
 /* Add debug info to the object file */
@@ -298,6 +313,15 @@ static void OptMnemonicColumn (const char* Opt, const char* Arg)
 
 
 
+static void OptMultiPass (const char* Opt attribute ((unused)),
+                         const char* Arg attribute ((unused)))
+/* Handle the --multi-pass option */
+{
+    MultiPass = 1;
+}
+
+
+
 static void OptPageLength (const char* Opt attribute ((unused)), const char* Arg)
 /* Handle the --pagelength option */
 {
@@ -590,15 +614,37 @@ static void OnePass (void)
 static void Disassemble (void)
 /* Disassemble the code */
 {
-    /* Pass 1 */
-    Pass = 1;
+    /* Preparation pass */
+    Pass = PASS_PREP;
     OnePass ();
 
+    /* If the --multi-pass option is given, repeat this pass until we have no
+    ** new labels.
+    */
+    if (MultiPass) {
+        unsigned long LabelCount = GetLabelCount ();
+        unsigned Passes = 1;
+        while (1) {
+            unsigned long NewLabelCount;
+            ResetCode ();
+            OnePass ();
+            CHECK(++Passes <= 4096);            /* Safety measure */
+            NewLabelCount = GetLabelCount ();
+            if (NewLabelCount <= LabelCount) {
+                break;
+            }
+            LabelCount = NewLabelCount;
+        }
+        if (Debug) {
+            printf ("Run %u preparation passes to resolve labels\n", Passes);
+        }
+    }
+
     Output ("---------------------------");
     LineFeed ();
 
-    /* Pass 2 */
-    Pass = 2;
+    /* Final pass */
+    Pass = PASS_FINAL;
     ResetCode ();
     OutputSettings ();
     DefOutOfRangeLabels ();
@@ -617,6 +663,7 @@ int main (int argc, char* argv [])
         { "--comment-column",   1,      OptCommentColumn        },
         { "--comments",         1,      OptComments             },
         { "--cpu",              1,      OptCPU                  },
+        { "--debug",            0,      OptDebug                },
         { "--debug-info",       0,      OptDebugInfo            },
         { "--formfeeds",        0,      OptFormFeeds            },
         { "--help",             0,      OptHelp                 },
@@ -624,6 +671,7 @@ int main (int argc, char* argv [])
         { "--info",             1,      OptInfo                 },
         { "--label-break",      1,      OptLabelBreak           },
         { "--mnemonic-column",  1,      OptMnemonicColumn       },
+        { "--multi-pass",       0,      OptMultiPass            },
         { "--pagelength",       1,      OptPageLength           },
         { "--start-addr",       1,      OptStartAddr            },
         { "--sync-lines",       0,      OptSyncLines            },
@@ -653,6 +701,14 @@ int main (int argc, char* argv [])
                     LongOption (&I, OptTab, sizeof(OptTab)/sizeof(OptTab[0]));
                     break;
 
+                case 'd':
+                    if (Arg[2] == '\0') {
+                        OptDebug (Arg, 0);
+                    } else {
+                        UnknownOption (Arg);
+                    }
+                    break;
+
                 case 'g':
                     OptDebugInfo (Arg, 0);
                     break;
@@ -665,6 +721,10 @@ int main (int argc, char* argv [])
                     OptInfo (Arg, GetArg (&I, 2));
                     break;
 
+                case 'm':
+                    OptMultiPass (Arg, 0);
+                    break;
+
                 case 'o':
                     OutFile = GetArg (&I, 2);
                     break;
diff --git a/src/da65/output.c b/src/da65/output.c
index bc5f7d5c2..13cb3e127 100644
--- a/src/da65/output.c
+++ b/src/da65/output.c
@@ -124,7 +124,7 @@ void CloseOutput (void)
 void Output (const char* Format, ...)
 /* Write to the output file */
 {
-    if (Pass == PassCount) {
+    if (Pass == PASS_FINAL) {
         va_list ap;
         va_start (ap, Format);
         Col += vfprintf (F, Format, ap);
@@ -137,7 +137,7 @@ void Output (const char* Format, ...)
 void Indent (unsigned N)
 /* Make sure the current line column is at position N (zero based) */
 {
-    if (Pass == PassCount) {
+    if (Pass == PASS_FINAL) {
         while (Col < N) {
             fputc (' ', F);
             ++Col;
@@ -150,7 +150,7 @@ void Indent (unsigned N)
 void LineFeed (void)
 /* Add a linefeed to the output file */
 {
-    if (Pass == PassCount) {
+    if (Pass == PASS_FINAL) {
         fputc ('\n', F);
         if (PageLength > 0 && ++Line >= PageLength) {
             if (FormFeeds) {
@@ -185,7 +185,7 @@ void DefForward (const char* Name, const char* Comment, unsigned Offs)
 ** current PC.
 */
 {
-    if (Pass == PassCount) {
+    if (Pass == PASS_FINAL) {
         /* Flush existing output if necessary */
         if (Col > 1) {
             LineFeed ();
@@ -212,7 +212,7 @@ void DefForward (const char* Name, const char* Comment, unsigned Offs)
 void DefConst (const char* Name, const char* Comment, uint32_t Addr)
 /* Define an address constant */
 {
-    if (Pass == PassCount) {
+    if (Pass == PASS_FINAL) {
         Output ("%s", Name);
         Indent (ACol);
         Output (":= $%04" PRIX32, Addr);
@@ -313,7 +313,7 @@ void DataDWordLine (uint32_t ByteCount)
 void SeparatorLine (void)
 /* Print a separator line */
 {
-    if (Pass == PassCount && Comments >= 1) {
+    if (Pass == PASS_FINAL && Comments >= 1) {
         Output ("; ----------------------------------------------------------------------------");
         LineFeed ();
     }
@@ -324,7 +324,7 @@ void SeparatorLine (void)
 void StartSegment (const char* Name, unsigned AddrSize)
 /* Start a segment */
 {
-    if (Pass == PassCount) {
+    if (Pass == PASS_FINAL) {
         LineFeed ();
         Output (".segment");
         Indent (ACol);
@@ -368,7 +368,7 @@ void LineComment (unsigned PC, unsigned Count)
 {
     unsigned I;
 
-    if (Pass == PassCount && Comments >= 2) {
+    if (Pass == PASS_FINAL && Comments >= 2) {
         Indent (CCol);
         Output ("; %04X", PC);
         if (Comments >= 3) {