Initial commit of files related to NED architecture.

[ned1] / nedasm / nedasm_parser_extensions.c

/*
* © 2018 Aaron Taylor <ataylor at subgeniuskitty dot com>
* See LICENSE.txt file for copyright and license details.
*/

#include <stdlib.h>
#include <string.h>

#include "nedasm_structures.h"
#include "nedasm_misc.h"

struct instruction *
parse_pseudo_mnemonic(char * mnemonic, size_t mnemonic_index, char * data, size_t data_index,
                     char * label, size_t label_index, struct instruction * new_instruction)
{
   uint32_t linenum = new_instruction->linenum;

   if (strncmp(mnemonic, "JSR", MAX_MNEMONIC_LEN) == 0) {
       if (label_index) {
           new_instruction->syllable = WORD;
           new_instruction->target = malloc(label_index+1);
           strncpy(new_instruction->target, label, label_index+1);
           new_instruction->next = create_instruction_struct();
           new_instruction->next->prev = new_instruction;
           new_instruction = new_instruction->next;
       }
       /* JSR must expand to exactly one word (five syllables).                        */
       /* Otherwise, trailing syllables in the same word are skipped when RTS returns. */
       // TODO: This should be on a word boundary, regardless of whether a WORD preceded it.
       for (int i=0; i<5; i++) {
           switch (i) {
               case 0:
                   new_instruction->syllable = IM;
                   new_instruction->data = 0x08; /* Address of PC register */
                   break;
               case 1:
                   new_instruction->syllable = LOAD;
                   break;
               case 2:
                   new_instruction->syllable = SWAP;
                   break;
               case 3:
                   new_instruction->syllable = JMP;
                   break;
               case 4:
                   new_instruction->syllable = NOP;
                   break;
               default:
                   break;
           }
           new_instruction->linenum = linenum;
           if (i<4) {
               new_instruction->next = create_instruction_struct();
               new_instruction->next->prev = new_instruction;
               new_instruction = new_instruction->next;
           }
       }
   } else if (strncmp(mnemonic, "RTS", MAX_MNEMONIC_LEN) == 0) {
       new_instruction->syllable = JMP;
   }

   return new_instruction;
}