The loader in Figure 8.3 executes with the following input: 04 00 05 00 00 31 00

Question

The loader in Figure 8.3 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 27th time. State the

values in the following registers as four hexadecimal digits:

*(e) A after ANDA at FC88

. The following program executes, generating an interrupt for DECI :

0000  040005          BR      mai n       ; Branch around data

0003  0000   num:      . BLOCK  2          ; Gl obal  vari abl e

;  

0005  310003 mai n:     DECI     num, d      ; I nput  deci mal  val ue

0008  390003          DECO    num, d      ; Out put deci mal  val ue

000B  50000A          CHARO   ' ' , i      

000E  410012          STRO    msg, d      ; Out put message

0011  00              STOP        0012  546861 msg:      . ASCI I   "That' s al l . "

742773

20616C

6C2E0A

00

001F                  . END               

For Figure 8.6, the entry to and exit from the trap handler, state the values in the fol-

lowing registers as four hexadecimal digits:

(c) X after SUBX at FCBA

Explanation / 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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