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Join Date: Nov 2005
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Newbie Poster
I'm writing a program in assebly using x86 intel processor series and a flat model
can anyome suggest anything about this?
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input string,40 ;the user enter a characher 'q' for instance
atod string ; now the value in eax as decimal
;;i need to compare the number and if is 'q' to quit
;;i've tried this senario
cmp eax,'q'
jz quit ;;;;;;not working
cmp al,'q' ;;;;;;not again
jz quit
cmp eax,113 ;;;;where 113 is the decimal ascii value of 'q'
jz quit
cmp al,113 ;;;;;nothing
jz quit
cmp al,71 ;;;i didnt not make the convertion here atod
;;and nothing again 71 is hex of 'q'
cmp eax,113 ;;;;same;;nothing
can anyone help?
Thanks in advance
;;;;;;;;;;;;;;;;;;;
can anyome suggest anything about this?
;;;;;;;;;;;;;;;;;;;
input string,40 ;the user enter a characher 'q' for instance
atod string ; now the value in eax as decimal
;;i need to compare the number and if is 'q' to quit
;;i've tried this senario
cmp eax,'q'
jz quit ;;;;;;not working
cmp al,'q' ;;;;;;not again
jz quit
cmp eax,113 ;;;;where 113 is the decimal ascii value of 'q'
jz quit
cmp al,113 ;;;;;nothing
jz quit
cmp al,71 ;;;i didnt not make the convertion here atod
;;and nothing again 71 is hex of 'q'
cmp eax,113 ;;;;same;;nothing
can anyone help?
Thanks in advance
;;;;;;;;;;;;;;;;;;;
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Junior Poster
What is the underlying operating system, or are you using BIOS calls.
In any event, EAX won't work because especially in the case of ASCII only an 8 bit value is returned and you are comparing a 32 bit value and may not know at any given time what the value of bits 31 - 8 are. Comparing cmp al,'q', should work except where caps lock may be on then you would have to compare against 'Q'. The method I usually use is to implement a case insensitive comparison where I'll convert all characters in AL to upper or lower case.
In any event, EAX won't work because especially in the case of ASCII only an 8 bit value is returned and you are comparing a 32 bit value and may not know at any given time what the value of bits 31 - 8 are. Comparing cmp al,'q', should work except where caps lock may be on then you would have to compare against 'Q'. The method I usually use is to implement a case insensitive comparison where I'll convert all characters in AL to upper or lower case.
mov al, [Character] and al, 0x5f cmp al,'Q' jz Done
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Newbie Poster
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Originally Posted by Tight_Coder_Ex
What is the underlying operating system, or are you using BIOS calls.
In any event, EAX won't work because especially in the case of ASCII only an 8 bit value is returned and you are comparing a 32 bit value and may not know at any given time what the value of bits 31 - 8 are. Comparing cmp al,'q', should work except where caps lock may be on then you would have to compare against 'Q'. The method I usually use is to implement a case insensitive comparison where I'll convert all characters in AL to upper or lower case.
mov al, [Character] and al, 0x5f cmp al,'Q' jz Done
Thanks Tight_Coder_Ex
You made it clear to me thanks.Problem solved.
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