/[gxemul]/trunk/src/cpus/cpu_m68k_instr.c
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revision 14 by dpavlin, Mon Oct 8 16:18:51 2007 UTC revision 32 by dpavlin, Mon Oct 8 16:20:58 2007 UTC
# Line 1  Line 1 
1  /*  /*
2   *  Copyright (C) 2005  Anders Gavare.  All rights reserved.   *  Copyright (C) 2005-2006  Anders Gavare.  All rights reserved.
3   *   *
4   *  Redistribution and use in source and binary forms, with or without   *  Redistribution and use in source and binary forms, with or without
5   *  modification, are permitted provided that the following conditions are met:   *  modification, are permitted provided that the following conditions are met:
# Line 25  Line 25 
25   *  SUCH DAMAGE.   *  SUCH DAMAGE.
26   *   *
27   *   *
28   *  $Id: cpu_m68k_instr.c,v 1.2 2005/09/17 17:14:27 debug Exp $   *  $Id: cpu_m68k_instr.c,v 1.8 2006/08/21 14:44:22 debug Exp $
29   *   *
30   *  Motorola 68K instructions.   *  Motorola 68K instructions.
31   *   *
32   *  Individual functions should keep track of cpu->n_translated_instrs. Since   *  Individual functions should keep track of cpu->n_translated_instrs.
  *  M68K uses variable length instructions, cpu->cd.m68k.next_ic must also be  
  *  increased by the number of "instruction slots" that were executed. (I.e.  
  *  if an instruction occupying 6 bytes was executed, then next_ic should be  
  *  increased by 3.)  
  *  
33   *  (n_translated_instrs is automatically increased by 1 for each function   *  (n_translated_instrs is automatically increased by 1 for each function
34   *  call. If no instruction was executed, then it should be decreased. If, say,   *  call. If no instruction was executed, then it should be decreased. If, say,
35   *  4 instructions were combined into one function and executed, then it should   *  4 instructions were combined into one function and executed, then it should
# Line 47  Line 42 
42   */   */
43  X(nop)  X(nop)
44  {  {
         cpu->cd.m68k.next_ic ++;  
45  }  }
46    
47    
# Line 72  X(end_of_page) Line 66  X(end_of_page)
66    
67    
68  /*  /*
  *  m68k_combine_instructions():  
  *  
  *  Combine two or more instructions, if possible, into a single function call.  
  */  
 void m68k_combine_instructions(struct cpu *cpu, struct m68k_instr_call *ic,  
         uint32_t addr)  
 {  
         int n_back;  
         n_back = (addr >> 1) & (M68K_IC_ENTRIES_PER_PAGE-1);  
   
         if (n_back >= 1) {  
                 /*  TODO  */  
         }  
   
         /*  TODO: Combine forward as well  */  
 }  
   
   
 /*****************************************************************************/  
   
   
 /*  
69   *  m68k_instr_to_be_translated():   *  m68k_instr_to_be_translated():
70   *   *
71   *  Translate an instruction word into an m68k_instr_call. ic is filled in with   *  Translate an instruction word into an m68k_instr_call. ic is filled in with
# Line 107  X(to_be_translated) Line 79  X(to_be_translated)
79          uint16_t iword;          uint16_t iword;
80          unsigned char *page;          unsigned char *page;
81          unsigned char ib[2];          unsigned char ib[2];
82          int main_opcode;          /* void (*samepage_function)(struct cpu *, struct m68k_instr_call *);*/
         void (*samepage_function)(struct cpu *, struct m68k_instr_call *);  
83    
84          /*  Figure out the (virtual) address of the instruction:  */          /*  Figure out the (virtual) address of the instruction:  */
85          low_pc = ((size_t)ic - (size_t)cpu->cd.m68k.cur_ic_page)          low_pc = ((size_t)ic - (size_t)cpu->cd.m68k.cur_ic_page)
# Line 135  X(to_be_translated) Line 106  X(to_be_translated)
106                  }                  }
107          }          }
108    
109          iword = *((uint16_t *)&ib[0]);          iword = (ib[0] << 8) + ib[1];
   
 #ifdef HOST_LITTLE_ENDIAN  
         iword = ((iword & 0xff) << 8) |  
                 ((iword & 0xff00) >> 8);  
 #endif  
   
   
         fatal("M68K: iword = 0x%04x\n", iword);  
110    
111    
112  #define DYNTRANS_TO_BE_TRANSLATED_HEAD  #define DYNTRANS_TO_BE_TRANSLATED_HEAD
# Line 153  X(to_be_translated) Line 116  X(to_be_translated)
116    
117          /*          /*
118           *  Translate the instruction:           *  Translate the instruction:
119             *
120             *  NOTE: The instruction length is assumed to be 2 bytes (1 slot)
121             *        if nothing else is specified.
122           */           */
123            ic->arg[0] = 1;
124    
125            switch (iword >> 12) {
126    
127  /*  TODO  */          case 0x4:
128                    switch ((iword >> 8) & 0xf) {
129    
130          main_opcode = iword;                  case 0xe:
131                            if ((iword & 0xff) == 0x71) {
132                                    ic->f = instr(nop);
133                                    break;
134                            }
135                            goto bad;
136    
137          switch (main_opcode) {                  default:goto bad;
138                    }
139                    break;
140    
141          default:goto bad;          default:goto bad;
142          }          }
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