Question

format of input file:

Col 1-8 label optional

Col 9 blank

Col 10 + optional

Col 11-17 mneumonic

Col 18 blank

Col 19 #, @, = ... optional

Col 20-29 (operand) label, register, ',',X optional ...

Col 30-31 blank

Col 32-80 comments optional (NO PERIOD REQUIRED)

In java I am writing a program to construct a symbol table and calculate addressses based off this args[0]:

Imput file format

LABEL INSTRUCTION OPERAND

imput.txt file.

ADDRES START 100 //This is the starting address  
. tests pc forward addressing
. tests base addressing
. tests pc backward addressing
NOW +LDB #BEGIN load base register // +LDB is a 4 byte instruction so next lines address is 104 (if a +is infront of instruction 4 bytes otherwise 3 bytes)
XXX BASE BEGIN tell assembler //assembler directive so next line addess stil 104
YYY LDA BE A <- (m..m+2) //LDA is a 3 byte instruction so next address is 107
EN RESW 4 //(Reserve words)RESW normally 3 byte instuction but 4 words so 12 bytes or C in hex, next address is 113
BE WORD 2 // WORD is 3 byte constant no matter how many, next address is 116
BEGIN RESW 1 // one RESW so add 3 bytes to previous address, next address is 119
JUNK RESW 2200 // 2200 RESW's = 6600 bytes(3*2200) = 19C8 in hex. So 19C8 +119 = next address 1AE1
THERE RESW 1 //RESW = 3 bytes next address is 1AE4
ZZZ LDA JUNK //LDA = 3 bytes next address is 1AE7
MMM STA THERE // STA = 3 bytes next address is 1AEA
END NOW

I want to write to a output file that caluclates the address and puts them on the left side. of the origional input file.

sample output file:

0100 ADDRES START 100
. tests pc forward addressing
. tests base addressing
. tests pc backward addressing
0100 NOW +LDB #BEGIN load base register
0104 XXX BASE BEGIN tell assembler  
0104 YYY LDA BE A <- (m..m+2)   
0107 EN RESW 4   
0113 BE WORD 2   
0116 BEGIN RESW 1
0119 JUNK RESW 2200   
1AE1 THERE RESW 1   
1AE4 ZZZ LDA JUNK
1AE7 MMM STA THERE   
1AEA END NOW

Answer 1

char firCol[8];                   //first 8 characters including delimiters
    char space[1] = {' '};            //guaranteed space
    char secCol[1] = {' '};           //space or '+'
    char thirCol[7];                  //word of length -7 but if shorter includes delitimers
    char forCol[1] = {' '};           //guaranteed space
    char fifCol[10];                  //sames of 7 but length
    char comm[52];                    // length 52 char and delimitrer

    memset(firCol, ' ', 8);
    memset(thirCol, ' ', 7);
    memset(comm, ' ', 52);

    f = fopen(argv[1], "r");                                                         

    memset(info, 0, sizeof(struct Account) * TABLE_SIZE);

      while(EOF != fscanf(f, "%8c %1c %1c %7c %1c %10c %52c", firCol, space, secCol, thirCol, forCol, fifCol, comm))
      {
        pass1(info, firCol, space, secCol, thirCol, forCol, fifCol, comm);
      }

OUTPUT:

    100    ADDRES   START    100                               
    100    NOW      +LDB     #BEGIN              LOAD BASE REGISTER 
    104    XXX       BASE     BEGIN              TELL ASSEMBLER  
    104    YYY       LDA      BE                 A <- (M..M+2)    
    107    EN        RESW     4                  
    113    BE        WORD     2                              
    116    BEGIN     RESW     1
    119    JUNK      RESW     2200                              
    1ae1   THERE     RESW     1                              
    1ae4   ZZZ       LDA      JUNK                               
    1ae7   MMM       STA      THERE                              
    1aea                END      NOW