util/ego/share/stack_chg.c

   1 /* $Id: stack_chg.c,v 1.6 1994/06/24 10:30:57 ceriel Exp $ */
   2 /*
   3  * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
   4  * See the copyright notice in the ACK home directory, in the file "Copyright".
   5  */
   6 /* S T A C K _ C H A N G E . C */
   7
   8
   9 #include <stdio.h>
  10 #include <em_spec.h>
  11 #include <em_mnem.h>
  12 #include "types.h"
  13 #include "debug.h"
  14 #include "global.h"
  15
  16 #include "pop_push.h"
  17
  18 #define IS_LOC(l)       (l!=(line_p) 0 && INSTR(l)==op_loc && TYPE(l)==OPSHORT)
  19
  20 int stack_change(l,sign)
  21         line_p l;
  22         char sign;
  23 {
  24         /* Interpret the string in the third column of the em_table file */
  25
  26         char *s;
  27         bool argdef;
  28         short arg = 0;
  29         int sum = 0;
  30         line_p p = PREV(l);
  31         line_p pp = (p == (line_p) 0 ? (line_p) 0 : PREV(p));
  32         short i = INSTR(l);
  33
  34         if (i < sp_fmnem || i > sp_lmnem) {
  35                 return 0;
  36         }
  37         if (TYPE(l) == OPSHORT) {
  38                 arg = SHORT(l);
  39                 if (arg < ws) {
  40                         /* E.g. a LOI 1 loads word-size bytes,
  41                          * not 1 byte!
  42                          */
  43                         arg = ws;
  44                 }
  45                 argdef = TRUE;
  46         } else {
  47                 argdef = FALSE;
  48         }
  49         s = pop_push[i];
  50         if (*s == '0') return 0;
  51         while (*s != '\0') {
  52                 if (*s++ == sign) {
  53                         switch(*s) {
  54                                 case 'w':
  55                                         sum +=  ws;
  56                                         break;
  57                                 case 'd':
  58                                         sum += 2 * ws;
  59                                         break;
  60                                 case 'p':
  61                                         sum += ps;
  62                                         break;
  63                                 case 'a':
  64                                         if (!argdef) return -1;
  65                                         sum +=  arg;
  66                                         break;
  67                                 case 'x':
  68                                         if (IS_LOC(p)) {
  69                                                 sum += SHORT(p);
  70                                                 break;
  71                                         } else {
  72                                                 return -1;
  73                                         }
  74                                 case 'y':
  75                                         if (IS_LOC(pp)) {
  76                                                 sum += SHORT(pp);
  77                                                 break;
  78                                         } else {
  79                                                 return -1;
  80                                         }
  81                                 case '?':
  82                                         return -1;
  83                                 default:
  84                                         assert(FALSE);
  85                         }
  86                 }
  87                 s++;
  88         }
  89         return sum;
  90 }
  91
  92
  93
  94 line_change(l,ok_out,pop_out,push_out)
  95         line_p l;
  96         bool *ok_out;
  97         int *pop_out,*push_out;
  98 {
  99         short pop,push;
 100
 101         pop = stack_change(l,'-');
 102         push = stack_change(l,'+');
 103         *ok_out = (pop != -1 && push != -1);
 104         *pop_out = pop;
 105         *push_out = push;
 106 }
 107
 108