Comments added.

diff --git a/util/ceg/EM_parser/common/default.c b/util/ceg/EM_parser/common/default.c
index cbe63cd..689185f 100644 (file)
--- a/util/ceg/EM_parser/common/default.c
+++ b/util/ceg/EM_parser/common/default.c
@@ -1,20 +1,9 @@
 #include "decl.h"
 #include <system.h>
 
-File   *save_file;
-extern File *outfile;
-extern char yytext[];
-int    def_start, def_end, save_lineno;
-extern int yylineno;
-
-init_defaults( instr)
-char *instr;
-{
-       save_file = outfile;
-       save_lineno = yylineno;
-       sys_open( ".default", OP_WRITE, &outfile);
-       set_def_params( instr);
-}
+/* This file contains a number of funtions which will be called to handle
+ * the 'DEF_C_INSTR' (e.g., C_loe).
+ */
 
 #define _ICON  0
 #define _UCON  4
@@ -86,7 +75,39 @@ struct { char *name; int segment, generated}
                /* C_ZRE */     { "C_zre", SEGTXT, 0},
                                { "C_zre_dnam", SEGTXT, 0},
                                { "C_zre_dlb", SEGTXT, 0}
-               };
+               };      /* This big array contains information about the 
+                        * functions that will be generated from the descrip-
+                        * tion of 1 DEF_C_INSTR. It contains the name, the
+                        * segment and a flag of these instructions. The flag
+                        * is used to determine if the instruction is explicitly
+                        * given in the EM_table or not.
+                        */
+
+
+File   *save_file;     /* Save original output-file in this variable */
+int    def_start,      /* Index in def_info[], start of the expanded C_INSTR */
+       def_end,        /* last expanded C_INSTR index. */
+       save_lineno;
+
+extern File *outfile;
+extern char yytext[];
+extern int yylineno;
+
+
+
+
+init_defaults( instr)
+char *instr;
+
+/* Save current output-file and write on a file called ".default" */
+
+{
+       save_file = outfile;
+       save_lineno = yylineno;
+       sys_open( ".default", OP_WRITE, &outfile);
+       set_def_params( instr);
+}
+
 
 int bss_or_hol_instr( index)
 int index;
@@ -96,10 +117,11 @@ int index;
                 index == _FCON + 2 || index == _FCON + 3);
 }
 
+
 set_def_params( instr)
 char *instr;
 
-/* geef def_start en def_end een waarde */
+/* Give 'def_start' and 'def_end' their correct values. */
 
 {
        int low, high, mid, rel;
@@ -130,7 +152,7 @@ char *instr;
                        else if ( rel < 0)
                                high = mid;
                        else
-                               /* pas op, mid is naar beneden afgerond !! */
+                               /* be careful : 'mid' is truncated */
                                low = ( mid == low ? low + 3: mid);
                }
                def_start = mid;
@@ -143,8 +165,9 @@ char *instr;
 
 handle_defaults()
 
-/* Zorgen dat de lexical-analyzer nu van de .default-file leest. */
-
+/* Switch back to original output-file and start generating the functions 
+ * from the file ".default".
+ */
 {
        FILE *old, *tmp, *switch_input();
        int i, old_yylineno;
@@ -165,11 +188,14 @@ handle_defaults()
 
                        set_outfile( def_info[i].name);
                        header( def_info[i].name);
-                       CD_pos = TRUE;  /* zet mylex() in juiste positie! */
+                       CD_pos = TRUE;  /* Set mylex() in correct state */
 
                        if ( bss_or_hol_instr( i)) {
                                extnd_header();
-                               /* Zorg voor de juiste $args */
+                               /* Rest of body is just the same as the corres-
+                                * ponding C_con_xxx C_rom_xxx instruction
+                                * so set correct info.
+                                */
                                set_C_instr_info( def_info[i-2].name);
                                def_row();
                                out( "}\n\n");
@@ -186,9 +212,10 @@ handle_defaults()
 
 def_admn( instr)
 char *instr;
+
+/* Mark this 'instr' as being generated */
+
 {
-       /* Noteer dat deze instructie gegenereerd is */
-       
        int low, high, mid, rel;
 
        low = _ICON;
@@ -205,13 +232,16 @@ char *instr;
                else if ( rel < 0)
                        high = mid;
                else
-                       /* pas op, mid is naar beneden afgerond !! */
                        low = ( mid == low ? low + 1: mid);
        }
        def_info[mid].generated = 1;
 }
 
 extnd_header()
+
+/* Generates code for loooking at the parameters 'nbytes' and 'i' of the
+ * bss an hol pseudo-instructions.
+ */
 {
        out( "if ( %s == 0 ) {\n", C_instr_info->arg_id[3]);
        set_segment( SEGBSS);