to DOS_ file_time (Chapter 7, Supplied) Suppose the time field of a file directo

Question

to DOS_ file_time (Chapter 7, Supplied) Suppose the time field of a file directory entry uses bits 0-4 for 2 hours (24-hour clock). Write a procedure ShowFi displays the time in hh:mm:ss format. binary 0 hh:mm:ss format: -second increments, bits 5-10 for minutes, and bits 11-15 for e named ShowFileTime that receives a binary file time value in the AX register and t. For example, the binary 0001 0010 0000 0111 indicates a time of 02:16:14, in 00010 010000 0011 For simplicity, we want to input 4-digit hexadecimal and show its binary to verify. For this, you can call ReadHex and WriteBinB. Then you can call your ShowFileTime to display the file time. You may call WriteDec, WriteChar, and consider prefixed zeros. Run your program; the screen will be like this C:TeachingcscI241KipIrvineSixthEditionProg_Ex_SMch07Debug project Please enter 16-bit hexadecimal (4-digit, e.g., 1207): A103 Your equivalent binary is 1010 0001 0000 0011 Your Dos file time is 20:08:06 c:TeachingcscI241KipIrvineSixthEditionProg_Ex_ SMch07Debug project Please enter 16-bit hexadecimal (4-digit, e.g., 1207): 1207 Your equivalent binary is 0001 0010 0000 0111 Your DOS file time is 02:16:14 Any reusable helper procedure is preferred, such as displaying a leading zero character if the value of hours, minutes, or seconds less than 10, else displaying an original two digits

Explanation / Answer

DOS_File_Time.asm

INCLUDE Irvine32.inc

.data

prompt1 BYTE "Please enter 16-bit hexadecimal (4-digit, e.g., 1207): ",0

prompt2 BYTE "Your equivalent binary is ",0

prompt3 BYTE "Your DOS file time is ",0

prompt4 BYTE "Sorry, invalid entry...", 0dh, 0ah, 0dh, 0ah, 0

.code

DOS PROC

mov edx,OFFSET prompt1

call WriteString

call ReadHex

call CheckFormat ;check format before outputting anything else

jz Error ;ZF=0 if valid

mov edx,OFFSET prompt2

call WriteString

mov ebx,TYPE WORD

call WriteBinB

call crlf

mov edx,OFFSET prompt3

call WriteString

call ShowFileTime

call crlf

call crlf

exit

Error:

mov edx,OFFSET prompt4

call WriteString

exit

DOS ENDP

;------------------------------------------------------------

CheckFormat PROC USES eax

mov ecx,eax

cmp eax,65535

ja Set

and ax,001Fh

cmp ax,29

ja Set

mov eax,ecx

and ax,07D0h

cmp ax,1888

ja Set

mov eax,ecx

and ax,0F800h

cmp ax,49152

ja Set

ret

Set:

and ecx,0

ret

CheckFormat ENDP

;------------------------------------------------------------

ShowFileTime PROC

;

; Displays file time in proper format

mov ecx,eax

mov edx,eax

shr ecx,11

call LeadingZero

mov al,':'

call WriteChar

mov ecx,edx

shr cx,5

and cx,3Fh

call LeadingZero

mov al,':'

call WriteChar

mov ecx,edx

and ecx,001Fh

mov eax,ecx

mov bx,2

mul bx

mov ecx,eax

call LeadingZero

ret

ShowFileTime ENDP

;------------------------------------------------------------

LeadingZero PROC

;

; Check if a number needs a leading zero and write it to the

cmp ecx,9

ja L1

mov eax,0

call WriteDec

L1: mov eax,ecx

call WriteDec

ret

LeadingZero ENDP

END DOS

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.