More work on GNU as generation

On _gas_mapping, label definitions do not allow "::". ":" must be
used instead.

gasOutput is now part of "options".

Unneeded sections, such as HOME/GSINIT/etc., are no longer declared
and/or defined. GNU as just does not need them.

Startup function name must equal "_start" for GNU ld.

The value of some macros, such as CODE_NAME or DATA_NAME, must change
according to options.gasOutput, as "CODE" or "DATA" (among many others)
are not understood by GNU as.

STM8 port now selects GNU as format on --gas switch enabled.

13 files changed, 179 insertions, 104 deletions

diff --git a/src/Makefile b/src/Makefile
index 692ac7e..8604fee 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -15,12 +15,12 @@ PORTS           = $(shell cat ../ports.build)
 ALLPORTS        = $(shell cat ../ports.all)
 PORT_LIBS       = $(PORTS:%=%/port.a)
 
-LIBS            = -lm
+LIBS            = -lm 
 
-CFLAGS          =  -pipe -ggdb -g -O2 -Wall -Wno-parentheses
-CXXFLAGS        = -pipe -ggdb -g -O2 -Wall -Wno-parentheses
+CFLAGS          =  -pipe -ggdb -g -Og -Wall -Wno-parentheses
+CXXFLAGS        = -pipe -ggdb -g -Og -Wall -Wno-parentheses
 CPPFLAGS        += -I$(srcdir)
-LDFLAGS         =
+LDFLAGS         = 
 
 ifdef SDCC_SUB_VERSION
 CFLAGS          += -DSDCC_SUB_VERSION_STR=\"$(SDCC_SUB_VERSION)\"
diff --git a/src/Makefile.dep b/src/Makefile.dep
index f67fbcf..f5ac324 100644
--- a/src/Makefile.dep
+++ b/src/Makefile.dep
@@ -198,7 +198,11 @@ SDCCgen.o: SDCCgen.c common.h SDCCglobl.h SDCCset.h ../sdccconf.h \
  SDCCsystem.h port.h SDCCargs.h ../support/util/newalloc.h \
  ../support/util/dbuf_string.h ../support/util/dbuf.h
 SDCCgas.o: SDCCgas.c SDCCgas.h SDCCglobl.h SDCCset.h ../sdccconf.h \
- SDCCerr.h ../support/util/newalloc.h
+ SDCCerr.h SDCCmem.h ../support/util/dbuf.h SDCCsymt.h SDCChasht.h \
+ SDCCval.h SDCCicode.h SDCCbitv.h SDCCast.h port.h SDCCargs.h SDCCpeeph.h \
+ SDCCgen.h SDCCicode.h SDCCbitv.h SDCCset.h SDCCast.h \
+ ../support/util/newalloc.h ../support/util/dbuf_string.h \
+ ../support/util/dbuf.h
 SDCClex.o: SDCClex.c common.h SDCCglobl.h SDCCset.h ../sdccconf.h \
  SDCCerr.h SDCCmem.h ../support/util/dbuf.h SDCCsymt.h SDCChasht.h \
  SDCCval.h SDCCast.h SDCCy.h SDCCbitv.h SDCCicode.h SDCClabel.h \
diff --git a/src/SDCCasm.c b/src/SDCCasm.c
index 27f7cd1..05551bd 100644
--- a/src/SDCCasm.c
+++ b/src/SDCCasm.c
@@ -401,7 +401,7 @@ err_no_line:
 }
 
 static const ASM_MAPPING _gas_mapping[] = {
-  {"labeldef", "%s::"},
+  {"labeldef", "%s:"},
   {"slabeldef", "%s:"},
   {"tlabeldef", "%05d$:"},
   {"tlabel", "%05d$"},
@@ -409,11 +409,12 @@ static const ASM_MAPPING _gas_mapping[] = {
   {"zero", "#0x00"},
   {"one", "#0x01"},
   {"area", ".section %s"},
-  {"areacode", ".section .text"},
-  {"areadata", ".section .bss"},
+  {"areacode", ".section %s"},
+  {"areadata", ".section %s"},
   {"areahome", ".section %s"},
   {"ascii", ".ascii \"%s\""},
-  {"ds", ".comm %d"},
+  {"comm", ".comm %s, %d, %d"},
+  {"local", ".local %s"},
   {"db", ".byte"},
   {"dbs", ".byte %s"},
   {"dw", ".word"},
@@ -433,7 +434,7 @@ static const ASM_MAPPING _gas_mapping[] = {
    "; Function %s\n"
    "; ---------------------------------"},
   {"functionlabeldef", "%s:"},
-  {"globalfunctionlabeldef", "%s::"},
+  {"globalfunctionlabeldef", "%s:"},
   {"los", "(%s & 0xFF)"},
   {"his", "(%s >> 8)"},
   {"hihis", "(%s >> 16)"},
diff --git a/src/SDCCdwarf2.c b/src/SDCCdwarf2.c
index 8041641..a5e8bd8 100644
--- a/src/SDCCdwarf2.c
+++ b/src/SDCCdwarf2.c
@@ -1805,8 +1805,6 @@ dwWriteLineNumbers (void)
     lp->begin_sequence = 1;
   while (lp)
     {
-      fprintf(dwarf2FilePtr, ";sdccrm - label [\"%s\"], line %d\n", lp->label, lp->line);
-
       dwWriteLineNumber (lp);
       if (lp->end_sequence && lp->next)
         lp->next->begin_sequence = 1;
diff --git a/src/SDCCgas.c b/src/SDCCgas.c
index b626ee3..8055b99 100644
--- a/src/SDCCgas.c
+++ b/src/SDCCgas.c
@@ -45,7 +45,7 @@ void gas_glue(void)
   int clean_dst = 0;
   const char *dst = fullDstFileName;
 
-  if (!gasOutput)
+  if (!options.gasOutput)
     {
       werror(W_ILLEGAL_OPT_COMBINATION, __FILE__, __FUNCTION__,
             "this function must only be called if GAS"
@@ -183,13 +183,21 @@ static void emit_rodata(FILE *const f)
 
                     printf("%s.%s\n", name, field->name);
 
-                    if (SPEC_LONG(ft))
+                    if (IS_LONG(ft))
                       {
-                        fprintf(f, "\t.long %d\n", ft->select.s.const_val.v_long);
+                        fprintf(f, "\t.long %d\n", SPEC_CVAL(ft).v_long);
+                      }
+                    else if (IS_INT(ft))
+                      {
+                        fprintf(f, "\t.word %d\n", SPEC_CVAL(ft).v_uint);
                       }
                     else if (SPEC_SHORT(ft))
                       {
-                        fprintf(f, "\t.hword %d\n", ft->select.s.const_val.v_int);
+                        fprintf(f, "\t.hword %d\n", SPEC_CVAL(ft).v_int);
+                      }
+                    else if (IS_CHAR(ft) || IS_BOOL(ft))
+                      {
+                        fprintf(f, "\t.byte %d\n", SPEC_CVAL(ft).v_char);
                       }
                   }
               }
diff --git a/src/SDCCglobl.h b/src/SDCCglobl.h
index b2abbf2..89e33de 100644
--- a/src/SDCCglobl.h
+++ b/src/SDCCglobl.h
@@ -260,7 +260,7 @@ struct options
     int cc_only;                /* compile only flag              */
     int intlong_rent;           /* integer & long support routines reentrant */
     int float_rent;             /* floating point routines are reentrant */
-    int out_fmt;                /* 0 = undefined, 'i' = intel Hex format, 's' = motorola S19 format, 'E' = elf format, 'e' = true ELF format, 'Z' = gb format */
+    int out_fmt;                /* 0 = undefined, 'i' = intel Hex format, 's' = motorola S19 format, 'E' = elf format, 'Z' = gb format */
     int cyclomatic;             /* print cyclomatic information */
     int noOverlay;              /* don't overlay local variables & parameters */
     int xram_movc;              /* use movc instead of movx to read xram (mcs51) */
@@ -328,6 +328,7 @@ struct options
     int max_allocs_per_node;    /* Maximum number of allocations / combinations considered at each node in the tree-decomposition based algorithms */
     bool noOptsdccInAsm;        /* Do not emit .optsdcc in asm */
     bool oldralloc;             /* Use old register allocator */
+    int gasOutput;              /* Output assembly in GNU as format */
   };
 
 /* forward definition for variables accessed globally */
@@ -362,7 +363,6 @@ extern struct optimize optimize;
 extern struct options options;
 extern unsigned maxInterrupts;
 extern int ignoreTypedefType;
-extern int gasOutput;
 
 /* Visible from SDCCmain.c */
 extern set *preArgvSet;
diff --git a/src/SDCCglue.c b/src/SDCCglue.c
index 8251c43..77a56ce 100644
--- a/src/SDCCglue.c
+++ b/src/SDCCglue.c
@@ -33,6 +33,11 @@
 
 symbol *interrupts[INTNO_MAX + 1];
 
+static void emit_ds_comm( struct dbuf_s *oBuf,
+                          const char *name,
+                          unsigned int size,
+                          unsigned int alignment);
+
 void printIval (symbol *, sym_link *, initList *, struct dbuf_s *, bool check);
 set *publics = NULL;            /* public variables */
 set *externs = NULL;            /* Variables that are declared as extern */
@@ -146,6 +151,9 @@ emitRegularMap (memmap *map, bool addPublics, bool arFlag)
   if (!map)
     return;
 
+  if (options.gasOutput && !map->syms)
+    return;
+
   if (addPublics)
     {
       /* PENDING: special case here - should remove */
@@ -154,7 +162,8 @@ emitRegularMap (memmap *map, bool addPublics, bool arFlag)
       else if (!strcmp (map->sname, DATA_NAME))
         {
           dbuf_tprintf (&map->oBuf, "\t!areadata\n", map->sname);
-          if (options.data_seg && strcmp (DATA_NAME, options.data_seg))
+          if (options.data_seg && strcmp (DATA_NAME, options.data_seg) && !options.gasOutput)
+            /* GNU as only needs .bss. */
             dbuf_tprintf (&map->oBuf, "\t!area\n", options.data_seg);
         }
       else if (!strcmp (map->sname, HOME_NAME))
@@ -366,10 +375,17 @@ emitRegularMap (memmap *map, bool addPublics, bool arFlag)
               dbuf_printf (&map->oBuf, "==.\n");
             }
           if (IS_STATIC (sym->etype) || sym->level)
-            dbuf_tprintf (&map->oBuf, "!slabeldef\n", sym->rname);
+            if (options.gasOutput)
+              dbuf_tprintf (&map->oBuf, "\t!local\n", sym->rname);
+            else
+              dbuf_tprintf (&map->oBuf, "!slabeldef\n", sym->rname);
           else
-            dbuf_tprintf (&map->oBuf, "!labeldef\n", sym->rname);
-          dbuf_tprintf (&map->oBuf, "\t!ds\n", (unsigned int) size & 0xffff);
+            if (options.gasOutput)
+            dbuf_tprintf (&map->oBuf, "!global\n", sym->rname);
+            else
+              dbuf_tprintf (&map->oBuf, "!labeldef\n", sym->rname);
+
+          emit_ds_comm(&map->oBuf, sym->rname, size & 0xffff, 1/* TBD */);
         }
 
       sym->ival = NULL;
@@ -518,7 +534,7 @@ initValPointer (ast *expr)
       while (t->left != NULL && t->opval.op != '[')
         t = t->left;
 
-      return valForStructElem (t, expr->right); 
+      return valForStructElem (t, expr->right);
     }
 
   return NULL;
@@ -854,7 +870,7 @@ printIvalType (symbol * sym, sym_link * type, initList * ilist, struct dbuf_s *o
     {
       if (!!(val = initPointer (ilist, type, 0)))
         {
-          int i, size = getSize (type), le = port->little_endian, top = (options.model == MODEL_FLAT24) ? 3 : 2;;         
+          int i, size = getSize (type), le = port->little_endian, top = (options.model == MODEL_FLAT24) ? 3 : 2;;
           dbuf_printf (oBuf, "\t.byte ");
           for (i = (le ? 0 : size - 1); le ? (i < size) : (i > -1); i += (le ? 1 : -1))
             {
@@ -867,7 +883,7 @@ printIvalType (symbol * sym, sym_link * type, initList * ilist, struct dbuf_s *o
 			    if (val->name && strlen (val->name) > 0)
                   dbuf_printf (oBuf, "(%s >> %d)", val->name, i * 8);
 				else
-                  dbuf_printf (oBuf, "#0x00");				
+                  dbuf_printf (oBuf, "#0x00");
               else
                 dbuf_printf (oBuf, "#0x00");
               if (i == (le ? (size - 1) : 0))
@@ -1983,8 +1999,12 @@ emitStaticSeg (memmap *map, struct dbuf_s *oBuf)
                 }
               else
                 {
-                  dbuf_printf (oBuf, "%s:\n", sym->rname);
-                  dbuf_tprintf (oBuf, "\t!ds\n", (unsigned int) size & 0xffff);
+                  if (options.gasOutput)
+                    dbuf_tprintf(oBuf, "\t!local\n", sym->rname);
+                  else
+                    dbuf_printf (oBuf, "%s:\n", sym->rname);
+
+                  emit_ds_comm(oBuf, sym->rname, size & 0xffff, 1/* TBD */);
                 }
             }
         }
@@ -2108,12 +2128,12 @@ createInterruptVect (struct dbuf_s *vBuf)
     }
 }
 
-char *iComments1 = {
+const char *iComments1 = {
   ";--------------------------------------------------------\n"
   "; File Created by SDCC : free open source ANSI-C Compiler\n"
 };
 
-char *iComments2 = {
+const char *iComments2 = {
   ";--------------------------------------------------------\n"
 };
 
@@ -2177,7 +2197,7 @@ emitOverlay (struct dbuf_s *aBuf)
       if (elementsInSet (ovrset))
         {
           /* output the area information */
-          dbuf_printf (aBuf, "\t.area\t%s\n", port->mem.overlay_name);  /* MOF */
+          dbuf_printf (aBuf, "\t!area\t%s\n", port->mem.overlay_name);  /* MOF */
         }
 
       for (sym = setFirstItem (ovrset); sym; sym = setNextItem (ovrset))
@@ -2224,16 +2244,21 @@ emitOverlay (struct dbuf_s *aBuf)
                 {
                   werrorfl (sym->fileDef, sym->lineDef, E_UNKNOWN_SIZE, sym->name);
                 }
-              /* print extra debug info if required */
-              if (options.debug)
+              /* print extra debug info if required. GNU as does not need this. */
+              if (options.debug && !options.gasOutput)
                 {
                   emitDebugSym (aBuf, sym);
                   dbuf_printf (aBuf, "==.\n");
                 }
 
               /* allocate space */
-              dbuf_tprintf (aBuf, "!slabeldef\n", sym->rname);
-              dbuf_tprintf (aBuf, "\t!ds\n", (unsigned int) getSize (sym->type) & 0xffff);
+              if (options.gasOutput)
+                /* .bss variables do not need a label definition on GNU as. */
+                dbuf_tprintf(aBuf, "\t!local\n", sym->rname);
+              else
+                dbuf_tprintf (aBuf, "!slabeldef\n", sym->rname);
+
+              emit_ds_comm(aBuf, sym->rname, getSize (sym->type) & 0xffff, 1/* TBD */);
             }
         }
     }
@@ -2458,10 +2483,31 @@ glue (void)
   /* create the stack segment MOF */
   if (mainf && IFFUNC_HASBODY (mainf->type))
     {
+      const char *const start_stack = "__start__stack";
+      const unsigned int size = 1;
+
       fprintf (asmFile, "%s", iComments2);
       fprintf (asmFile, "; Stack segment in internal ram \n");
       fprintf (asmFile, "%s", iComments2);
-      fprintf (asmFile, "\t.area\tSSEG\n" "__start__stack:\n\t.ds\t1\n\n");
+
+      if (options.gasOutput)
+        {
+          char section_name[100];
+
+          snprintf( section_name, sizeof section_name / sizeof *section_name,
+                    ".%s", start_stack);
+          /* Set alloc/write flags. */
+          tfprintf(asmFile, "\t!area , \"aw\", @progbits\n", section_name);
+          tfprintf(asmFile, "\t!local\n", start_stack);
+          tfprintf(asmFile, "\t!comm\n\n", start_stack, size, 1);
+        }
+      else
+        {
+          tfprintf(asmFile, "\t!area\n", "SSEG");
+          tfprintf(asmFile, "\t!labeldef\n", start_stack);
+          tfprintf(asmFile, "\t!ds\n\n", size);
+          tfprintf(asmFile, "\t!area\n" "__start__stack:\n", "SSEG");
+        }
     }
 
   /* create the idata segment */
@@ -2539,8 +2585,9 @@ glue (void)
       dbuf_write_and_destroy (&xidata->oBuf, asmFile);
     }
 
-  /* If the port wants to generate any extra areas, let it do so. */
-  if (port->extraAreas.genExtraAreaDeclaration)
+  /* If the port wants to generate any extra areas, let it do so.
+   * This is not needed for GNU as, though. */
+  if (port->extraAreas.genExtraAreaDeclaration && !options.gasOutput)
     {
       port->extraAreas.genExtraAreaDeclaration (asmFile, mainf && IFFUNC_HASBODY (mainf->type));
     }
@@ -2559,16 +2606,24 @@ glue (void)
   fprintf (asmFile, "; global & static initialisations\n");
   fprintf (asmFile, "%s", iComments2);
 
-  /* Everywhere we generate a reference to the static_name area,
-   * (which is currently only here), we immediately follow it with a
-   * definition of the post_static_name area. This guarantees that
-   * the post_static_name area will immediately follow the static_name
-   * area.
-   */
-  tfprintf (asmFile, "\t!area\n", port->mem.home_name);
-  tfprintf (asmFile, "\t!area\n", port->mem.static_name);       /* MOF */
-  tfprintf (asmFile, "\t!area\n", port->mem.post_static_name);
-  tfprintf (asmFile, "\t!area\n", port->mem.static_name);
+  if (!options.gasOutput)
+    {
+      /* Everywhere we generate a reference to the static_name area,
+       * (which is currently only here), we immediately follow it with a
+       * definition of the post_static_name area. This guarantees that
+       * the post_static_name area will immediately follow the static_name
+       * area.
+       */
+      tfprintf (asmFile, "\t!area\n", port->mem.home_name);
+      tfprintf (asmFile, "\t!area\n", port->mem.static_name);       /* MOF */
+      tfprintf (asmFile, "\t!area\n", port->mem.post_static_name);
+      tfprintf (asmFile, "\t!area\n", port->mem.static_name);
+    }
+
+  if (options.gasOutput)
+    {
+      tfprintf (asmFile, "\t!areacode\n", CODE_NAME);
+    }
 
   if (mainf && IFFUNC_HASBODY (mainf->type))
     {
@@ -2600,19 +2655,22 @@ glue (void)
         fprintf (asmFile, "\t%cjmp\t__sdcc_program_startup\n", options.acall_ajmp ? 'a' : 'l');
     }
 
-  fprintf (asmFile, "%s" "; Home\n" "%s", iComments2, iComments2);
-  tfprintf (asmFile, "\t!areahome\n", HOME_NAME);
-  dbuf_write_and_destroy (&home->oBuf, asmFile);
+  if (!options.gasOutput)
+    {
+      fprintf (asmFile, "%s" "; Home\n" "%s", iComments2, iComments2);
+      tfprintf (asmFile, "\t!areahome\n", HOME_NAME);
+      dbuf_write_and_destroy (&home->oBuf, asmFile);
+    }
 
   if (mainf && IFFUNC_HASBODY (mainf->type))
     {
       /* STM8 note: there is no need to call main().
-         Instead of that, it's address is specified in the 
+         Instead of that, its address is specified in the
          interrupts table and always equals to 0x8080.
        */
 
       /* entry point @ start of HOME */
-      fprintf (asmFile, "__sdcc_program_startup:\n");
+      tfprintf (asmFile, "!labeldef\n", "__sdcc_program_startup");
 
       /* put in jump or call to main */
       if(TARGET_IS_STM8)
@@ -2623,6 +2681,7 @@ glue (void)
         fprintf (asmFile, "\t%cjmp\t_main\n", options.acall_ajmp ? 'a' : 'l');        /* needed? */
       fprintf (asmFile, ";\treturn from main will return to caller\n");
     }
+
   /* copy over code */
   fprintf (asmFile, "%s", iComments2);
   fprintf (asmFile, "; code\n");
@@ -2672,3 +2731,13 @@ isTargetKeyword (const char *s)
   return 0;
 }
 
+static void emit_ds_comm( struct dbuf_s *const oBuf,
+                          const char *const name,
+                          const unsigned int size,
+                          const unsigned int alignment)
+{
+  if (options.gasOutput)
+   dbuf_tprintf(oBuf, "\t!comm\n", name, size, alignment);
+  else
+    dbuf_tprintf(oBuf, "\t!ds\n", size);
+}
diff --git a/src/SDCCmain.c b/src/SDCCmain.c
index b20ef66..d83195a 100644
--- a/src/SDCCmain.c
+++ b/src/SDCCmain.c
@@ -65,7 +65,6 @@ struct optimize optimize;
 struct options options;
 int preProcOnly = 0;
 int noAssemble = 0;
-int gasOutput;
 set *preArgvSet = NULL;         /* pre-processor arguments  */
 set *asmOptionsSet = NULL;      /* set of assembler options */
 set *linkOptionsSet = NULL;     /* set of linker options */
@@ -174,7 +173,7 @@ static const OPTION optionsTable[] = {
   {'M', NULL, NULL, "Preprocessor option"},
   {'W', NULL, NULL, "Pass through options to the pre-processor (p), assembler (a) or linker (l)"},
   {'S', NULL, &noAssemble, "Compile only; do not assemble or link"},
-  {0  , "--gas", &gasOutput, "Compile only in GAS (GNU Assembler) format. Incompatible with other assembly or compilation options."},
+  {0  , "--gas", &options.gasOutput, "Compile in GAS (GNU Assembler) format."},
   {'c', "--compile-only", &options.cc_only, "Compile and assemble, but do not link"},
   {'E', "--preprocessonly", &preProcOnly, "Preprocess only, do not compile"},
   {0,   "--c1mode", &options.c1mode, "Act in c1 mode.  The standard input is preprocessed code, the output is assembly code."},
@@ -1490,12 +1489,6 @@ parseCmdLine (int argc, char **argv)
         }
     }
 
-  if (gasOutput && noAssemble)
-    {
-      /* Incompatible assembly output formats. */
-      werror(W_ILLEGAL_OPT_COMBINATION);
-    }
-
   /* some sanity checks in c1 mode */
   if (options.c1mode)
     {
@@ -1518,7 +1511,7 @@ parseCmdLine (int argc, char **argv)
       deleteSet (&relFilesSet);
       deleteSet (&libFilesSet);
 
-      if (options.cc_only || noAssemble || preProcOnly || gasOutput)
+      if (options.cc_only || noAssemble || preProcOnly || options.gasOutput)
         {
           werror (W_ILLEGAL_OPT_COMBINATION);
         }
@@ -1598,7 +1591,7 @@ parseCmdLine (int argc, char **argv)
     }
 
   /* if debug option is set then open the cdbFile */
-  if (options.debug && fullSrcFileName)
+  if (options.debug && fullSrcFileName && !options.gasOutput)
     {
       struct dbuf_s adbFile;
 
@@ -2608,6 +2601,8 @@ main (int argc, char **argv, char **envp)
     port->init ();
 
   setDefaultOptions ();
+
+  parseCmdLine (argc, argv);
 #ifdef JAMIN_DS390
   if (ds390_jammed)
     {
@@ -2616,8 +2611,6 @@ main (int argc, char **argv, char **envp)
     }
 #endif
 
-  parseCmdLine (argc, argv);
-
   if (options.verbose && NULL != port->processor)
     printf ("Processor: %s\n", port->processor);
 
@@ -2648,7 +2641,8 @@ main (int argc, char **argv, char **envp)
   initMem ();
 
   /* finalize target specific options */
-  port->finaliseOptions ();
+  if (port->finaliseOptions)
+    port->finaliseOptions();
 
   /* finalize common options */
   finalizeOptions ();
@@ -2675,18 +2669,8 @@ main (int argc, char **argv, char **envp)
       if (fatalError)
         exit (EXIT_FAILURE);
 
-      if (gasOutput)
-        {
-          if (port->general.gas_glue)
-            port->general.gas_glue();
-          else
-          {
-            werror(W_ILLEGAL_OPT_COMBINATION, __FILE__, __LINE__, "selected target does not support GNU assembler output");
-            exit (1);
-          }
-        }
-      else if (port->general.do_glue != NULL)
-        (*port->general.do_glue) ();
+      if (port->general.do_glue)
+        port->general.do_glue();
       else
         {
           /* this shouldn't happen */
@@ -2698,7 +2682,7 @@ main (int argc, char **argv, char **envp)
       if (fatalError)
         exit (EXIT_FAILURE);
 
-      if (!options.c1mode && !noAssemble)
+      if (!options.c1mode && !noAssemble && !options.gasOutput)
         {
           if (options.verbose)
             printf ("sdcc: Calling assembler...\n");
@@ -2710,7 +2694,7 @@ main (int argc, char **argv, char **envp)
   if (options.debug && debugFile)
     debugFile->closeFile ();
 
-  if (!options.cc_only && !fatalError && !noAssemble && !options.c1mode && (fullSrcFileName || peekSet (relFilesSet) != NULL))
+  if (!options.cc_only && !fatalError && !noAssemble && !options.gasOutput && !options.c1mode && (fullSrcFileName || peekSet (relFilesSet) != NULL))
     {
       if (options.verbose)
         printf ("sdcc: Calling linker...\n");
@@ -2723,4 +2707,3 @@ main (int argc, char **argv, char **envp)
 
   return 0;
 }
-
diff --git a/src/SDCCmem.c b/src/SDCCmem.c
index 550ee38..c1d8721 100644
--- a/src/SDCCmem.c
+++ b/src/SDCCmem.c
@@ -145,7 +145,7 @@ initMem ()
      DEBUG-NAME     -   'C'
      POINTER-TYPE   -   CPOINTER
    */
-  code = allocMap (0, 1, 0, 0, 0, 1, options.code_loc, CODE_NAME, 'C', CPOINTER);
+  code = allocMap (0, 1, 0, 0, 0, 1, options.code_loc, DATA_NAME, 'C', CPOINTER);
 
   /* home  segment ;
      SFRSPACE       -   NO
@@ -223,13 +223,13 @@ initMem ()
   if (OVERLAY_NAME)
       overlay = allocMap (0, 0, 0, 1, 0, 0, options.data_loc, DATA_NAME, 'E', POINTER);
 
-  /* Xternal paged segment ;   
+  /* Xternal paged segment ;
      SFRSPACE       -   NO
      FAR-SPACE      -   NO
      PAGED          -   YES
      DIRECT-ACCESS  -   NO
      BIT-ACCESS     -   NO
-     CODE-ACCESS    -   NO 
+     CODE-ACCESS    -   NO
      DEBUG-NAME     -   'P'
      POINTER-TYPE   -   PPOINTER
    */
@@ -664,7 +664,7 @@ allocParms (value *val, bool smallc)
             }
           else                      /* use internal stack   */
             {
-              
+
               SPEC_OCLS (lval->etype) = SPEC_OCLS (lval->sym->etype) = istack;
               if ((port->stack.direction > 0) != smallc)
                 {
@@ -1048,7 +1048,7 @@ clearStackOffsets (void)
        sym = setNextItem (istack->syms))
     {
       const int size = getSize (sym->type);
-      
+
       /* nothing to do with parameters so continue */
       if ((sym->_isparm && !IS_REGPARM (sym->etype)))
         continue;
@@ -1093,7 +1093,7 @@ redoStackOffsets (void)
           /* Remove them all, and let btree_alloc() below put them back in more efficiently. */
           currFunc->stack -= size;
           SPEC_STAK (currFunc->etype) -= size;
-      
+
           if(IS_AGGREGATE (sym->type) || sym->allocreq)
             btree_add_symbol (sym);
         }
diff --git a/src/SDCCmem.h b/src/SDCCmem.h
index ddfea0b..8e1bc56 100644
--- a/src/SDCCmem.h
+++ b/src/SDCCmem.h
@@ -48,10 +48,10 @@ extern FILE *junkFile;
 /* memory map prefixes  MOF added the DATA,CODE,XDATA,BIT */
 #define  XSTACK_NAME       port->mem.xstack_name
 #define  ISTACK_NAME       port->mem.istack_name
-#define  CODE_NAME         port->mem.code_name
-#define  DATA_NAME         port->mem.data_name
-#define  INITIALIZED_NAME  port->mem.initialized_name
-#define  INITIALIZER_NAME  port->mem.initializer_name
+#define  CODE_NAME         (options.gasOutput ? ".text" : port->mem.code_name)
+#define  DATA_NAME         (options.gasOutput ? ".bss" : port->mem.data_name)
+#define  INITIALIZED_NAME  (options.gasOutput ? ".data" : port->mem.data_name)
+#define  INITIALIZER_NAME  (options.gasOutput ? ".data.rodata" : port->mem.data_name)
 #define  IDATA_NAME        port->mem.idata_name
 #define  PDATA_NAME        port->mem.pdata_name
 #define  XDATA_NAME        port->mem.xdata_name
@@ -60,9 +60,9 @@ extern FILE *junkFile;
 #define  BIT_NAME          port->mem.bit_name
 #define  REG_NAME          port->mem.reg_name
 #define  STATIC_NAME       port->mem.static_name
-#define  HOME_NAME         port->mem.home_name
+#define  HOME_NAME         (options.gasOutput ? ".text.interrupt_vector" : port->mem.home_name)
 #define  OVERLAY_NAME      port->mem.overlay_name
-#define  CONST_NAME        port->mem.const_name
+#define  CONST_NAME        (options.gasOutput ? ".rodata" : port->mem.const_name)
 #define  CABS_NAME         port->mem.cabs_name
 #define  XABS_NAME         port->mem.xabs_name
 #define  IABS_NAME         port->mem.iabs_name
diff --git a/src/pdk/main.c b/src/pdk/main.c
index 21b1fc2..d28f2d4 100644
--- a/src/pdk/main.c
+++ b/src/pdk/main.c
@@ -68,8 +68,8 @@ pdk_genAssemblerEnd (FILE *of)
 int
 pdk_genIVT(struct dbuf_s *oBuf, symbol **intTable, int intCount)
 {
-  dbuf_tprintf (oBuf, "\t.area\tHEADER (ABS)\n");
-  dbuf_tprintf (oBuf, "\t.org\t 0x0020\n");
+  dbuf_tprintf (oBuf, "\t!area\tHEADER (ABS)\n");
+  dbuf_tprintf (oBuf, "\t!org\t 0x0020\n");
   if (interrupts[0])
     dbuf_tprintf (oBuf, "\tgoto\t%s\n", interrupts[0]->rname);
   else
@@ -85,7 +85,7 @@ pdk_genInitStartup (FILE *of)
   fprintf (of, "\t.org 0x00\n");
   fprintf (of, "p::\n");
   fprintf (of, "\t.ds 2\n");
-  
+
 
   fprintf (of, "\t.area\tHEADER (ABS)\n"); // In the header we have 16 bytes. First should be nop.
   fprintf (of, "\t.org 0x0000\n");
@@ -316,7 +316,7 @@ PORT pdk13_port =
      0,
      2,
      1,                         /* sp points to next free stack location */
-  },     
+  },
   { -1, false },                /* no int x int -> long multiplication support routine. */
   { 0,
     {
@@ -482,7 +482,7 @@ PORT pdk14_port =
      0,
      2,
      1,                         /* sp points to next free stack location */
-  },     
+  },
   { -1, false },                /* no int x int -> long multiplication support routine. */
   { 0,
     {
@@ -648,7 +648,7 @@ PORT pdk15_port =
      0,
      2,
      1,                         /* sp points to next free stack location */
-  },     
+  },
   { -1, false },                /* no int x int -> long multiplication support routine. */
   { 0,
     {
diff --git a/src/port.h b/src/port.h
index 6f11b58..360e091 100644
--- a/src/port.h
+++ b/src/port.h
@@ -217,8 +217,8 @@ typedef struct
      * due to ugly implementation in gbz80 target;
      * this should be fixed in src/z80/main.c (borutr)
      */
-    const char *code_name;
-    const char *data_name;
+    const char *const code_name;
+    const char *const data_name;
     const char *const idata_name;
     const char *const pdata_name;
     const char *const xdata_name;
diff --git a/src/stm8/main.c b/src/stm8/main.c
index 49731a0..c183137 100644
--- a/src/stm8/main.c
+++ b/src/stm8/main.c
@@ -30,6 +30,7 @@
 #include "dbuf_string.h"
 #include "peep.h"
 #include "SDCCgas.h"
+#include "SDCCglobl.h"
 
 #define OPTION_MEDIUM_MODEL         "--model-medium"
 #define OPTION_LARGE_MODEL          "--model-large"
@@ -154,7 +155,6 @@ stm8_genAssemblerEnd (FILE *of)
 static void
 stm8_init (void)
 {
-  asm_addTree (&asm_asxxxx_mapping);
 }
 
 
@@ -187,6 +187,8 @@ stm8_parseOptions (int *pargc, char **argv, int *i)
 static void
 stm8_finaliseOptions (void)
 {
+  asm_addTree (options.gasOutput ? &asm_gas_mapping : &asm_asxxxx_mapping);
+
   port->mem.default_local_map = data;
   port->mem.default_globl_map = data;
 
@@ -238,7 +240,11 @@ stm8_genExtraArea (FILE *of, bool hasMain)
 static void
 stm8_genInitStartup (FILE *of)
 {
-  fprintf (of, "__sdcc_gs_init_startup:\n");
+  const char *const startup = options.gasOutput ?
+                                "_start"
+                              : "__sdcc_gs_init_startup";
+
+  tfprintf (of, "!labeldef\n", startup);
 
   if (options.stack_loc >= 0)
     {
@@ -247,7 +253,7 @@ stm8_genInitStartup (FILE *of)
     }
 
   /* Init static & global variables */
-  fprintf (of, "__sdcc_init_data:\n");
+  tfprintf (of, "!labeldef\n", "__sdcc_init_data");
   fprintf (of, "; stm8_genXINIT() start\n");
 
   /* Zeroing memory (required by standard for static & global variables) */
@@ -277,7 +283,13 @@ int
 stm8_genIVT(struct dbuf_s * oBuf, symbol ** intTable, int intCount)
 {
   int i;
-  dbuf_tprintf (oBuf, "\tint s_GSINIT ; reset\n");
+
+  if (options.gasOutput)
+    {
+      dbuf_tprintf(oBuf, "!area , \"ax\", @progbits\n", ".text.__interrupt");
+    }
+
+  dbuf_tprintf(oBuf, "\tint s_GSINIT ; reset\n");
 
   if(intCount > STM8_INTERRUPTS_COUNT)
     {