Any help would be awesome. Im beyond stuck and have no clue whats going on. Any

Question

Any help would be awesome. Im beyond stuck and have no clue whats going on. Any help would be a beyond great. Ill put the question down below, thanks agian.

2e.  The loader in Figure 8.3(shown below) executes with the following input:

04  00  05 00  00  31  00  03 39  00  03 50  00  0A 41  00                 

12  00  54 68  61  74  27  73 20  61  6C 6C 2E 0A  00  zz

Assume that the loop from FC5D to FC97 is executing for the 27thtime.  State the values in the following registers as four hexadecimal digits:

A after ANDA at FC88

Figure 8.3

; ******* Syst em Loader
; Data must be in the following format:
; Each hex number representing a byte must contain
; exactly two characters.  Each character must be
; i n 0. . 9,  A. . F,  or a. . f and must  be followed by exact l y
; one space.  There must be no leading spaces at the beginning
; of a line and no trailing spaces at the end of a line.  The last two
; characters in the fi l e must  be lowercase zz,  which is used as t he
; terminating sentinel  by the loader.
;
FC57  C80000 loader:   LDX     0, i         ; X : = 0
FC5A  E9FC4F          STX     wordBuff, d ; Clear input  buffer word
FC57  C80000 loader:   LDX     0, i         ; X : = 0
FC5A  E9FC4F          STX     wordBuff, d ; Clear input  buffer word
;
FC5D  49FC50 get Char:  CHARI    byteBuff, d ; Get  first  hex character
FC60  C1 FC4F          LDA     wordBuff, d ; Put  ASCI I into low byte of A
FC63  B0007A          CPA     ' z' , i       ; I f end of fi l e sentinel  ' z'
FC66  0AFC9A          BREQ    stopLoad   ; then exit  loader routine
FC69  B00039          CPA     ' 9' , i       ; If character <= ' 9' ,  assume decimal
FC6C  06FC72          BRLE    shift       ; and right  nybble is correct  digit
FC6F  700009          ADDA    9, i         ; else convert  nybble to correct  digit
FC72  1 C     shift :    ASLA               ; Shift  left by four bits to send
FC73  1 C              ASLA               ; the digit  to the most significant
FC74  1 C              ASLA               ; position in the byte
FC75  1 C              ASLA
FC76  F1 FC52          STBYTEA byteTemp, d ; Save the most  significant  nibble
FC79  49FC50          CHARI    byteBuff, d ; Get  second hex character
FC7C  C1 FC4F          LDA     wordBuff, d ; Put  ASCI I into low byte of A
FC7F  B00039          CPA     ' 9' , i       ; I f character <= ' 9' ,  assume decimal
FC82  06FC88          BRLE    combine    ; and right  nybble is correct  digit
FC85  700009          ADDA    9, i         ; else convert  nybble to correct  digit
FC88  90000F combine:  ANDA    0x000F, i    ; Mask out  the left nibble
FC8B  A1 FC51           ORA     wordTemp, d ; Combine bot h hex digits in binary
FC8E  F50000          STBYTEA 0, x        ; St ore in Mem[ X]
FC91   780001           ADDX    1 , i         ; X : = X + 1
FC94  49FC50          CHARI    byteBuff, d ; Skip blank or <LF>
FC97  04FC5D          BR      get Char    ;
;
FC9A  00     stopLoad: STOP               ;

Explanation / Answer

Answer

Object

Addr code Symbol Mnemon Operand Comment

0000 04000D BR main ;Branch around data

0003 0000 num: .BLOCK 2 ;Storage for one integer

0005 202B20 msg: .ASCII " + 1 = "

31203D

2000

;

000D 310003 main: DECI num,d ;Get the number

0010 390003 DECO num,d ;and output it

0013 410005 STRO msg,d ;Output ' + 1 = '

0016 C10003 LDA num,d ;A := the number

0019 700001 ADDA 1,i ;Add one to it

001C E10003 STA num,d ;Store the sum

001F 390003 DECO num,d ;Output the sum

0022 00 STOP

0023 .END

Symbol table:

Symbol Value Symbol Value

main 000D msg 0005

num 0003

Input

-479

Output

-479 + 1 = -478

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