comma delimiters in decimal numbers

He everybody, hope somebody finds this useful, if not maybe next time hehe,

I needed a method to put commas in my decimal numbers awhile ago cuz otherwise they way too hard to read. So I looked around but didn't find anything so I came up with this algo. It starts at the most significant end of the number thus overcoming some problems. It works quite good:) It is based on the observation that if any integer is divided by 3 the remainder (edx) follows this pattern:

edx = 0 then first comma is 3 places counting from left
edx = 2 then first comma is 2 places counting from left
edx = 1 then first comma is 1 places counting from left

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;adds comma delimiters where required
;szNumber is equal to decimal number e.g 49152
;dwNumberDigits is string length
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

CommaProc proc uses edi edx szNumber:DWORD,dwNumberDigits:DWORD

LOCAL buffer[256]:BYTE

mov eax,dwNumberDigits
cmp eax,03h ;if only three digits no commas
jle @fini
mov ecx,03h
xor edx,edx
div ecx
xor ecx,ecx
mov ecx,dwNumberDigits

.if edx==00h
add edx,03h
lea edi,buffer
mov esi,szNumber

@@:
cmp ecx,00h
jz @end
cmp edx,00h
jz @AddDelimiter1
lodsb
stosb
sub ecx,01h
sub edx,01h
jmp @b

@AddDelimiter1:
mov eax,2ch
stosb
mov edx,03h
jmp @b

.elseif edx==01h
lea edi,buffer
mov esi,szNumber

@@:
cmp ecx,00h
jz @end
cmp edx,00h
jz @AddDelimiter2
lodsb
stosb
sub ecx,01h
sub edx,01h
jmp @b

@AddDelimiter2:
mov eax,2ch
stosb
mov edx,03h
jmp @b

.elseif edx==02h
lea edi,buffer
mov esi,szNumber

@@:
cmp ecx,00h
jz @end
cmp edx,00h
jz @AddDelimiter3
lodsb
stosb
sub ecx,01h
sub edx,01h
jmp @b

@AddDelimiter3:
mov eax,2ch
stosb
mov edx,03h
jmp @b

.endif

@end:
mov eax,00h
stosb
invoke lstrcpy,Addr szTotalBytes,Addr buffer
;this is your new comma delimited decimal
; number, do what you want
@fini:

ret

CommaProc endp
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

Posted on 2001-12-29 17:52:07 by czDrillard

This is more than 20 times faster:



The Svin ?

InsertComma proc len,lpszStringIn,lpStringOut

	mov esi,lpszStringIn

	mov edi,lpszStringOut

	mov ecx,-1

	mov eax,len



@@:	inc ecx

	sub eax,3

	jnbe @B

	test ecx,ecx ;if length less than 4

	je lastmove

	mov edx,[esi]

	add eax,3

	mov [edi],edx

	add esi,eax

	mov byte ptr [edi][eax],2Ch

	dec ecx

	lea edi,[edi][eax][1]

	je lastmove



@@:	mov eax,[esi]

	add esi,3

	mov al,2Ch

	dec ecx

	mov [edi],eax

	lea edi,[edi][4]

	jne @B

lastmove:

	mov eax,[esi]

	mov [edi],eax

	ret

InsertComma endp

Posted on 2002-01-15 04:46:08 by The Svin

comma delimiters in decimal numbers

Thanks guys !

I have seen a C code from Jeffrey Richter that does that things too... I don't remember if it uses the same method but it can be worth a look...

Posted on 2002-01-16 05:10:57 by JCP

comma delimiters in decimal numbers

I doubt

Posted on 2002-01-28 01:35:24 by The Svin

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