isupper

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jInuQ

Joined: 26 Jun 2003
Posts: 48
Location: USA - NV

jInuQ 09 Feb 2004, 21:19

will this do what I think it should?

Code:

proc isupper, char
enter
        mov al, byte [char]
        cmp al, 0x41 ; this is 'A' 8^)
        jl NOTUPPER
        cmp al, 0x5A ; this is 'Z' 8^)
        jg NOTUPPER

        mov eax, 1
        jmp @f

        NOTUPPER:
        xor eax, eax

        @@:
        return
leave

_________________
jInuQ

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away."
- Antoine de Saint Exupery

09 Feb 2004, 21:19

JohnFound

Joined: 16 Jun 2003
Posts: 3499
Location: Bulgaria

JohnFound 09 Feb 2004, 23:13

It seems yes, but some optimization whould be good. And probably unsigned jcc is more apropriate in this situation: ja/jb instead of jg/jl

Regards.

09 Feb 2004, 23:13

ronware

Joined: 08 Jan 2004
Posts: 179
Location: Israel

ronware 09 Feb 2004, 23:18

It's ok only for ASCII (English). You will need a table if you want to properly uppercase/lowercase for other languages.

09 Feb 2004, 23:18

jInuQ

Joined: 26 Jun 2003
Posts: 48
Location: USA - NV

jInuQ 10 Feb 2004, 00:05

JohnFond,
Thanks for the info I will change it to ja. Make more sense that way any how.

ronware,
Yeah, right now english is the only langue I need. At some point it might be interesting to do something in unicode.

_________________
jInuQ

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away."
- Antoine de Saint Exupery

10 Feb 2004, 00:05

Bitdog

Joined: 18 Jan 2004
Posts: 97

Bitdog 10 Feb 2004, 03:15

TEST AL,00100000b ;english
JZ isUPPER ;JMP if bit-5 is clear

---new edit below-----
In the english CPU alphebet 0-255
the value of 'a' is exactly 00100000b greater than 'A'
toggling bit-5 swaps case from 'A' to 'a' & back. A-Z & a-z
There are afew other characters that use the same bit-5
so under some circumstances you could alter the value of a non A-Z alph
but for the purposes of checking, or a quickie check,
TEST AL,0010000b
JNZ BITisSET ;seems to work ok.

AND AL,11011111b ; to upper case
OR AL,00100000b ; to lower case

Last edited by Bitdog on 11 Feb 2004, 08:31; edited 1 time in total

10 Feb 2004, 03:15

jInuQ

Joined: 26 Jun 2003
Posts: 48
Location: USA - NV

jInuQ 11 Feb 2004, 01:46

Okay, you going to need to break down you logic. I grok what the AND does ,but don't see why your doing it? A little help? 8^)

_________________
jInuQ

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away."
- Antoine de Saint Exupery

11 Feb 2004, 01:46

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