X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=as%2Fxa51%2Fxa_main.c;h=345ca7e4ec44498a524c0ff0e3430715f88149c7;hb=d08e6df2202ed3f19b681221b502dedb3c6c8a28;hp=da706284161df2f86953f57c0b24559411a522ca;hpb=46c48126418a6f6b861d07cbb8205535cec267f7;p=fw%2Fsdcc

diff --git a/as/xa51/xa_main.c b/as/xa51/xa_main.c
index da706284..345ca7e4 100644
--- a/as/xa51/xa_main.c
+++ b/as/xa51/xa_main.c
@@ -17,32 +17,74 @@
 /* adapted from the osu8asm project, 1995 */
 /* http://www.pjrc.com/tech/osu8/index.html */
 
+/* 
+   made "relocatable" by johan.knol@iduna.nl for sdcc
+   
+   This isn't a standalone assembler anymore. It's only purpose is to
+   create relocatable modules (that has to be processed with xa_link) 
+   out of sdcc-generated .xa files
+*/
+
+#define D(x) x
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <limits.h>
 
-#include "xa_main.h"
+#define printf(x...) fprintf(stderr,x)
 
+#include "xa_main.h"
+#include "xa_version.h"
 extern void yyrestart(FILE *new_file);
-extern void hexout(int byte, int memory_location, int end);
 extern int yyparse();
 
 
+char modulename[PATH_MAX];
+char infilename[PATH_MAX];
+char outfilename[PATH_MAX];
+char listfilename[PATH_MAX];
+char symfilename[PATH_MAX];
+
 /* global variables */
 
-FILE *fhex, *fmem, *list_fp;
+FILE *frel, *fmem, *list_fp, *sym_fp;
 extern FILE *yyin;
 extern char *yytext;
 extern char last_line_text[];
 struct symbol *sym_list=NULL;
 struct target *targ_list=NULL;
-int lineno=1, mem=0;   /* mem is location in memory */
+int lineno=1;
 int p1=0, p2=0, p3=0;
 int expr_result, expr_ok, jump_dest, inst;
-int opcode, operand;
+int opcode;
 char symbol_name[1000];
+struct area_struct area[NUM_AREAS];
+int current_area=0;
+
+char rel_line[2][132];
+
+char *areaToString (int area) {
+  switch (area) 
+    {
+    case AREA_CSEG: return "CSEG";
+    case AREA_DSEG: return "DSEG";
+      //case AREA_OSEG: return "OSEG";
+      //case AREA_ISEG: return "ISEG";
+    case AREA_BSEG: return "BSEG";
+    case AREA_XSEG: return "XSEG";
+    case AREA_XISEG: return "XISEG";
+    case AREA_XINIT: return "XINIT";
+    case AREA_GSINIT: return "GSINIT";
+      //case AREA_GSFINAL: return "GSFINAL";
+      //case AREA_HOME: return "HOME";
+      //case AREA_SSEG: return "SSEG";
+    }
+  return ("UNKNOW");
+}
 
+/* "mem" is replaced by area[current_area].alloc_position */
+/* int mem=0; */   /* mem is location in memory */
 
 /* add symbols to list when we find their definition in pass #1 */
 /* we will evaluate their values in pass #2, and figure out if */
@@ -53,7 +95,16 @@ struct symbol * build_sym_list(char *thename)
 {
 	struct symbol *new, *p;
 
-/*	printf("  Symbol: %s  Line: %d\n", thename, lineno); */
+	if ((p=findSymbol(thename))) {
+	  if (p->isdef) {
+	    fprintf (stderr, "error: symbol %s already defined\n", thename);
+	    exit (1);
+	  } else {
+	    return p;
+	  }
+	}
+
+	//printf("  Symbol: %s  Line: %d\n", thename, lineno);
 	new = (struct symbol *) malloc(sizeof(struct symbol));
 	new->name = (char *) malloc(strlen(thename)+1);
 	strcpy(new->name, thename);
@@ -63,6 +114,8 @@ struct symbol * build_sym_list(char *thename)
 	new->isbit = 0;
 	new->isreg = 0;
 	new->line_def = lineno - 1;
+	new->area = current_area;
+	new->mode = 'X'; // start with an external
 	new->next = NULL;
 	if (sym_list == NULL) return (sym_list = new);
 	p = sym_list;
@@ -71,24 +124,35 @@ struct symbol * build_sym_list(char *thename)
 	return (new);
 }
 
-int assign_value(char *thename, int thevalue)
-{
-	struct symbol *p;
+struct symbol *findSymbol (char *thename) {
+  struct symbol *p;
+  for (p=sym_list; p; p=p->next) {
+    if (strcasecmp(thename, p->name)==0) {
+      return p;
+    }
+  }
+  return NULL;
+}
 
-	p = sym_list;
- 	while (p != NULL) {
-		if (!(strcasecmp(thename, p->name))) {
-			p->value = thevalue;
-			p->isdef = 1;
-			return (0);
-		}
-		p = p->next;
-	}
-	fprintf(stderr, "Internal Error!  Couldn't find symbol\n");
-	exit(1);
+int assign_value(char *thename, int thevalue, char mode) {
+  struct symbol *p;
+  
+  p = sym_list;
+  while (p != NULL) {
+    if (!(strcasecmp(thename, p->name))) {
+      p->area=current_area;
+      p->value = thevalue;
+      p->isdef = 1;
+      p->mode = mode;
+      return (0);
+    }
+    p = p->next;
+  }
+  fprintf(stderr, "Internal Error!  Couldn't find symbol\n");
+  exit(1);
 }
 
-int mk_bit(char *thename)
+int mk_bit(char *thename, int area)
 {
         struct symbol *p;
 
@@ -96,6 +160,24 @@ int mk_bit(char *thename)
         while (p != NULL) {
                 if (!(strcasecmp(thename, p->name))) {
                         p->isbit = 1;
+			p->area = area;
+                        return (0);
+                }
+                p = p->next;
+        }
+        fprintf(stderr, "Internal Error!  Couldn't find symbol\n");
+        exit(1);
+}
+
+int mk_sfr(char *thename)
+{
+        struct symbol *p;
+
+        p = sym_list;
+        while (p != NULL) {
+                if (!(strcasecmp(thename, p->name))) {
+                        p->issfr = 1;
+			p->area = 0;
                         return (0);
                 }
                 p = p->next;
@@ -121,19 +203,36 @@ int mk_reg(char *thename)
         exit(1);
 }
 
-
+int mk_global(char *thename)
+{
+  struct symbol *p;
+  
+  p = sym_list;
+  while (p != NULL) {
+    if (!(strcasecmp(thename, p->name))) {
+      p->global = 1;
+      return (0);
+    }
+    p = p->next;
+  }
+  fprintf(stderr, "Internal Error!  Couldn't find symbol\n");
+  exit(1);
+}
 
 int get_value(char *thename)
 {
-	struct symbol *p;
-	p = sym_list;
-	while (p != NULL) {
-		if (!(strcasecmp(thename, p->name)))
-			return (p->value);
-		p = p->next;
-	}
-	fprintf(stderr, "Internal Error!  Couldn't find symbol value\n");
-	exit(1);
+  struct symbol *p;
+  p = sym_list;
+  while (p != NULL) {
+    if (!(strcasecmp(thename, p->name))) {
+      if (p->mode=='=')
+	;//return 0;
+      return (p->value);
+    }
+    p = p->next;
+  }
+  fprintf(stderr, "Internal Error!  Couldn't find symbol value\n");
+  exit(1);
 }
 		
 
@@ -175,39 +274,57 @@ void flag_targets()
 
 void print_symbol_table()
 {
-	struct symbol *p;
-	p = sym_list;
-	while (p != NULL) {
-		printf("Sym:%12s = %5d (%04X)  Def:", \
-		  p->name, p->value, p->value);
-		if (p->isdef) printf("Yes"); else printf("No ");
-		printf("  Bit:");
-		if (p->isbit) printf("Yes"); else printf("No ");
-		printf("  Target:");
-		if (p->istarget) printf("Yes"); else printf("No ");
-		printf(" Line %d\n", p->line_def);
-		p = p->next;
-	}
+  struct symbol *p;
+  p = sym_list;
+  while (p != NULL) {
+#if 0
+    fprintf(sym_fp, "Sym in %-5s: %s\n", areaToString(p->area), p->name);
+    fprintf(sym_fp, "  at: 0x%04X (%5d)", p->value, p->value);
+    fprintf(sym_fp, " Def:%s", p->isdef ? "Yes" : "No ");
+    fprintf(sym_fp, " Bit:%s", p->isbit ? "Yes" : "No ");
+    fprintf(sym_fp, " Target:%s", p->istarget ? "Yes" : "No ");
+    fprintf(sym_fp, " Line %d\n", p->line_def);
+#else
+    if (p->issfr) {
+      fprintf (sym_fp, "%-7s", "SFR");
+    } else if (p->isbit && !p->area) {
+      fprintf (sym_fp, "%-7s", "SBIT");
+    } else if (p->mode=='=') {
+      fprintf (sym_fp,"ABS    ");
+    } else if (!p->isdef) {
+      fprintf (sym_fp,"EXTRN  ");
+    } else {
+      fprintf (sym_fp, "%-7s", areaToString(p->area));
+    }
+    fprintf (sym_fp, " 0x%04x (%5d)", p->value, p->value);
+    fprintf (sym_fp, " %s", p->isdef ? "D" : "-");
+    fprintf (sym_fp, "%s", p->isbit ? "B" : "-");
+    fprintf (sym_fp, "%s", p->istarget ? "T" : "-");
+    fprintf (sym_fp, " %s\n", p->name);
+#endif
+    p = p->next;
+  }
 }
 
 /* check that every symbol is in the table only once */
 
 void check_redefine()
 {
-	struct symbol *p1, *p2;
-	p1 = sym_list;
-	while (p1 != NULL) {
-		p2 = p1->next;
-		while (p2 != NULL) {
-			if (!strcasecmp(p1->name, p2->name)) {
-				fprintf(stderr, "Error: symbol '%s' redefined on line %d", p1->name, p2->line_def);
-				fprintf(stderr, ", first defined on line %d\n", p1->line_def);
-			exit(1);
-			}
-			p2 = p2->next;
-		}
-		p1 = p1->next;
-	}
+  struct symbol *p1, *p2;
+  p1 = sym_list;
+  while (p1 != NULL) {
+    p2 = p1->next;
+    while (p2 != NULL) {
+      if (!strcasecmp(p1->name, p2->name)) {
+	fprintf(stderr, "Error: symbol '%s' redefined on line %d", 
+		p1->name, p2->line_def);
+	fprintf(stderr, ", first defined on line %d\n", p1->line_def);
+	exit(1);
+      }
+      p2 = p2->next;
+    }
+    p1 = p1->next;
+  }
 }
 
 int is_target(char *thename)
@@ -244,15 +361,38 @@ int is_reg(char *thename)
 }
 
 
-int is_def(char *thename)
+struct symbol *is_def(char *thename)
 {
-	struct symbol *p;
-	p = sym_list;
-	while (p != NULL) {
-		if (!strcasecmp(thename, p->name) && p->isdef) return(1);
-		p = p->next;
-	}
-	return (0);
+  struct symbol *p;
+  p = sym_list;
+  while (p != NULL) {
+    if (!strcasecmp(thename, p->name) && p->isdef) 
+      return p;
+    p = p->next;
+  }
+  return NULL;
+}
+
+struct symbol *is_ref(char *thename) {
+  struct symbol *p;
+  p = sym_list;
+  while (p != NULL) {
+    if (strcasecmp(thename, p->name)==0) 
+      return p;
+    p = p->next;
+  }
+  return NULL;
+}
+
+int is_abs(char *thename) {
+  struct symbol *p;
+  p = sym_list;
+  while (p != NULL) {
+    if (strcasecmp(thename, p->name)==0) 
+      return p->mode == '=';
+    p = p->next;
+  }
+  return 0;
 }
 
 /* this routine is used to dump a group of bytes to the output */
@@ -262,31 +402,81 @@ int is_def(char *thename)
 /* though is it expected that the lexer has placed all the actual */
 /* original text from the line in "last_line_text" */
 
-void out(int *byte_list, int num)
-{
-	int i, first=1;
-
-	if (num > 0) fprintf(list_fp, "%06X: ", mem);
-	else fprintf(list_fp, "\t");
-
-	for (i=0; i<num; i++) {
-		hexout(byte_list[i], mem+i, 0);
-		if (!first && (i % 4) == 0) fprintf(list_fp, "\t");
-		fprintf(list_fp, "%02X", byte_list[i]);
-		if ((i+1) % 4 == 0) {
-			if (first) fprintf(list_fp, "\t%s\n", last_line_text);
-			else fprintf(list_fp, "\n");
-			first = 0;
-		} else {
-			if (i<num-1) fprintf(list_fp, " ");
-		}
+static short last_area=-1;
+
+int debug=0;
+
+void out(int *byte_list, int num) {
+  struct symbol *p;
+  int i, first=1;
+  
+  if (num > 0) fprintf(list_fp, "%06X: ", MEM_POS);
+  else fprintf(list_fp, "\t");
+  
+  if (last_area!=current_area) {
+    // emit area information
+    if (area[current_area].size) {
+      fprintf (frel, "A %s size %d flags 0\n", 
+	       areaToString(current_area),
+	       area[current_area].size);
+      if  (!area[current_area].defsEmitted) {
+	for (p=sym_list; p; p=p->next) {
+	  if (p->global && p->isdef && p->area==current_area) {
+	    // skip temp labels
+	    if (p->name[strlen(p->name)-1]!='$') {
+	      if (p->mode=='=') {
+		fprintf (frel, "S %s Abs%04x\n", p->name, p->value);
+	      } else {
+		fprintf (frel, "S %s Def%04x\n", p->name, p->value);
+	      }
+	    }
+	  }
+	}
+	area[current_area].defsEmitted=1;
+      }
+    }
+    last_area=current_area;
+  }
+  if (current_area==AREA_CSEG ||
+      current_area==AREA_GSINIT ||
+      current_area==AREA_XINIT) {
+    if (num) {
+      for (i=0; i<num; i++) {
+	if ((i%16)==0) {
+	  fprintf (frel, "%sT %04x", i ? "\n" : "", MEM_POS+i);
 	}
-	if (first) {
-		if (num < 3) fprintf(list_fp, "\t");
-		fprintf(list_fp, "\t%s\n", last_line_text);
-	} else {
-		if (num % 4) fprintf(list_fp, "\n");
+	fprintf (frel, " %02x", byte_list[i]);
+      }
+      fprintf (frel, "\n");
+      if (rel_line[0][0]) {
+	fprintf (frel, "%s\n", rel_line[0]);
+	if (rel_line[1][0]) {
+	  fprintf (frel, "%s\n", rel_line[1]);
 	}
+      }
+    }
+    for (i=0; i<num; i++) {
+      if (!first && (i % 4) == 0) fprintf(list_fp, "\t");
+      fprintf(list_fp, "%02X", byte_list[i]);
+      if ((i+1) % 4 == 0) {
+	if (first) fprintf(list_fp, "\t%s\n", last_line_text);
+	else fprintf(list_fp, "\n");
+	first = 0;
+      } else {
+	if (i<num-1) fprintf(list_fp, " ");
+      }
+    }
+  }
+  if (first) {
+    if (num < 3) fprintf(list_fp, "\t");
+    fprintf(list_fp, "\t%s\n", last_line_text);
+  } else {
+    if (num % 4) fprintf(list_fp, "\n");
+  }
+  operand[0][0]='\0';
+  operand[1][0]='\0';
+  rel_line[0][0]='\0';
+  rel_line[1][0]='\0';
 }
 
 
@@ -294,14 +484,16 @@ void out(int *byte_list, int num)
 
 void pad_with_nop()
 {
-	static int nops[] = {NOP_OPCODE, NOP_OPCODE, NOP_OPCODE, NOP_OPCODE};
-	int num;
-
-	last_line_text[0] = '\0';
-
-	for(num=0; (mem + num) % BRANCH_SPACING; num++) ;
-	if (p3) out(nops, num);
-	mem += num;
+  static int nops[] = {NOP_OPCODE, NOP_OPCODE, NOP_OPCODE, NOP_OPCODE};
+  int num;
+  
+  last_line_text[0] = '\0';
+  
+  for(num=0; (MEM_POS + num) % BRANCH_SPACING; num++) {
+    sprintf (last_line_text, "\tnop\t; word allignment");
+  }
+  if (p3) out(nops, num);
+  MEM_POS += num;
 }
 
 /* print branch out of bounds error */
@@ -313,27 +505,6 @@ void boob_error()
 	exit(1);
 }
 
-/* output the jump either direction on carry */
-/* jump_dest and mem must have the proper values */
-
-/* 
-void do_jump_on_carry()
-{
-	if (p3) {
-		operand = REL4(jump_dest, mem);
-		if (operand < 0) {
-			operand *= -1;
-			operand -= 1;
-			if (operand > 15) boob_error();
-			out(0x20 + (operand & 15));
-		} else {
-			if (operand > 15) boob_error();
-			out(0x30 + (operand & 15));
-		}
-	}
-}
-*/ 
-
 /* turn a string like "10010110b" into an int */
 
 int binary2int(char *str)
@@ -347,7 +518,107 @@ int binary2int(char *str)
 	return (sum);
 }
 
-void print_usage();
+void print_usage(int);
+
+void init_areas(void)
+{
+  area[AREA_CSEG].start=area[AREA_CSEG].alloc_position = 0;
+  area[AREA_DSEG].start=area[AREA_DSEG].alloc_position = 0;
+  area[AREA_BSEG].start=area[AREA_BSEG].alloc_position = 0;
+  area[AREA_XSEG].start=area[AREA_XSEG].alloc_position = 0;
+  area[AREA_XISEG].start=area[AREA_XISEG].alloc_position = 0;
+  area[AREA_XINIT].start=area[AREA_XINIT].alloc_position = 0;
+  area[AREA_GSINIT].start=area[AREA_GSINIT].alloc_position = 0;
+  area[AREA_GSFINAL].start=area[AREA_GSFINAL].alloc_position = 0;
+  area[AREA_HOME].start=area[AREA_HOME].alloc_position = 0;
+}
+
+void relPrelude() {
+  //char buffer[132];
+  int i, areas=0, globals=0;
+  struct symbol *p;
+
+  fprintf (frel, "SDCCXA rel, version %1.1f\n", version);
+  for (i=1; i<NUM_AREAS; i++) {
+    if ((area[i].size=area[i].alloc_position-area[i].start)) {
+      areas++;
+    }
+  }
+  for (p=sym_list; p; p=p->next) {
+    if (p->isdef) {
+      // skip temp labels
+      if (p->name[strlen(p->name)-1]!='$') {
+	globals++;
+      }
+    }
+  }
+  fprintf (frel, "H %d areas %d global symbols\n", areas, globals);
+  fprintf (frel, "M %s\n", modulename);
+  for (p=sym_list; p; p=p->next) {
+    if (!p->isdef) {
+      fprintf (frel, "S %s Ref0000\n", p->name);
+    }
+  }
+}
+
+void printVersion() {
+  printf("\nPaul's XA51 Assembler\n");
+  printf("Copyright 1997,2002 Paul Stoffregen\n\n");
+  printf("This program is free software; you can redistribute it\n");
+  printf("and/or modify it under the terms of the GNU General Public\n");
+  printf("License, Version 2, published by the Free Software Foundation\n\n");
+  printf("This program is distributed in the hope that it will be useful,\n");
+  printf("but WITHOUT ANY WARRANTY; without even the implied warranty of\n");
+  printf("MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\n");
+}
+
+int verbose=0, createSymbolFile=0;
+
+void process_args(int argc, char **argv) 
+{
+  int i=0;
+
+  if (argc < 2) print_usage(1);
+  
+  while (++i<argc && *argv[i]=='-') {
+    if (strcmp(argv[i], "--version")==0) {
+      printVersion();
+      exit (0);
+    }
+    if (strcmp(argv[i], "--help")==0) {
+      print_usage(0);
+    }
+    if (strcmp(argv[i], "-v")==0) {
+      verbose++;
+      continue;
+    }
+    if (strcmp(argv[i], "-s")==0) {
+      createSymbolFile++;
+      continue;
+    }
+    print_usage(1);
+  }
+
+  if (i!=argc-1) {
+    // only 1 source file for now
+    print_usage(1);
+  }
+
+  strcpy(infilename, argv[i]);
+
+  if (strncasecmp(infilename+strlen(infilename)-4, ".asm", 3)) {
+    fprintf (stderr, "unrecognized input file: \"%s\"\n", argv[i]);
+    print_usage(1);
+  }
+
+  strcpy(modulename, infilename);
+  modulename[strlen(modulename)-4] = '\0';
+  sprintf (outfilename, "%s.rel", modulename);
+  sprintf (listfilename, "%s.lst", modulename);
+  if (createSymbolFile) {
+    sprintf (symfilename, "%s.sym", modulename);
+  }
+}
 
 /* pass #1 (p1=1) find all symbol defs and branch target names */
 /* pass #2 (p2=1) align branch targets, evaluate all symbols */
@@ -355,26 +626,15 @@ void print_usage();
 
 int main(int argc, char **argv)
 {
-	char infilename[200], outfilename[200], listfilename[200];
-
-	if (argc < 2) print_usage();
-	strcpy(infilename, argv[1]);
-	if(strlen(infilename) > 3) {
-		if (strncasecmp(infilename+strlen(infilename)-3, ".xa", 3))
-			strcat(infilename, ".xa");
-	} else strcat(infilename, ".xa");
-	strcpy(outfilename, infilename);
-	outfilename[strlen(outfilename)-3] = '\0';
-	strcpy(listfilename, outfilename);
-	strcat(outfilename, ".hex");
-	strcat(listfilename, ".lst");
+	process_args (argc, argv);
+
 	yyin = fopen(infilename, "r");
 	if (yyin == NULL) {
 		fprintf(stderr, "Can't open file '%s'.\n", infilename);
 		exit(1);
 	}
-	fhex = fopen(outfilename, "w");
-	if (fhex == NULL) {
+	frel = fopen(outfilename, "w");
+	if (frel == NULL) {
 		fprintf(stderr, "Can't write file '%s'.\n", outfilename);
 		exit(1);
 	}
@@ -383,53 +643,66 @@ int main(int argc, char **argv)
 		fprintf(stderr, "Can't write file '%s'.\n", listfilename);
 		exit(1);
 	}
+	if (createSymbolFile) {
+	  sym_fp = fopen(symfilename, "w");
+	  if (sym_fp == NULL) {
+	    fprintf(stderr, "Can't write file '%s'.\n", symfilename);
+	    exit(1);
+	  }
+	}
 
-	/* todo: add a command line option to supress verbose messages */
-	printf("\nPaul's XA51 Assembler\n");
-	printf("Copyright 1997,2002 Paul Stoffregen\n\n");
-	printf("This program is free software; you can redistribute it\n");
-	printf("and/or modify it under the terms of the GNU General Public\n");
-	printf("License, Version 2, published by the Free Software Foundation\n\n");
-	printf("This program is distributed in the hope that it will be useful,\n");
-	printf("but WITHOUT ANY WARRANTY; without even the implied warranty of\n");
-	printf("MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\n");
-
-
-
-	printf("    Building Symbol Table:\n");
+	if (verbose) printf("Pass 1: Building Symbol Table:\n");
 	p1 = 1;
-	mem = 0;
+	init_areas();
 	yyparse();
 	flag_targets();
-	// print_symbol_table();
 	check_redefine();
+
+	if (verbose) printf("Pass 2: Aligning Branch Targets:\n");
 	p1 = 0;
 	p2 = 1;
 	rewind(yyin);
 	yyrestart(yyin);
 	lineno = 1;
-	printf("    Aligning Branch Targets:\n");
-	mem = 0;
+	init_areas();
 	yyparse();
-	// print_symbol_table();
+
+	relPrelude();
+	if (createSymbolFile) print_symbol_table();
+
+	if (verbose) printf("Pass 3: Generating Object Code:\n");
 	p2 = 0;
 	p3 = 1;
 	rewind(yyin);
 	yyrestart(yyin);
 	lineno = 1;
-	printf("    Generating Object Code:\n");
-	mem = 0;
+	init_areas();
 	yyparse();
+
 	fclose(yyin);
-	hexout(0, 0, 1);  /* flush and close intel hex file output */
 	return 0;
 }
 
 
-void print_usage()
+void print_usage(int fatal)
 {
-	fprintf(stderr, "Usage: xa_asm file\n");
-	fprintf(stderr, "   or  xa_asm file.asm\n");
-	exit(1);
+  FILE *out = fatal ? stderr : stdout;
+
+  fprintf (out, "Usage: xa_asm [-s] [-v] file.xa\n");
+  fprintf (out, "  -v            verbose: show progress\n");
+  fprintf (out, "  -s            create symbol file\n");
+  fprintf (out, "  --version     show version/copyright info and exit\n");
+  fprintf (out, "  --help        show this and exit\n");
+#if 0
+  // some usefull options I can think of.
+  fprintf (out, "  -m            create map file\n");
+  fprintf (out, "  -ss           create symbol file sorted by symbol\n");
+  fprintf (out, "  -sa           create symbol file sorted by segment/address\n");
+  fprintf (out, "  --no-temps    supress temp symbols in map and sym file\n");
+  fprintf (out, "  --code-loc=#  sets the start address of the code\n");
+  fprintf (out, "  --xdata-loc=# sets the start address of the external data\n");
+  fprintf (out, "  --stack-loc=# sets the start address of the stack\n");
+#endif
+  exit(fatal);
 }