Replace bytes
in [ASM]
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From: almas on 13 Apr 2008 07:46 OK : i add dec DI, all ri right ! Below the code.... but why a push and a pop ? mov cx, byte size_file mov si, offset come_from ; 1st file mov di, offset go_to ; the new file push ds ; What do thoose 3 lines ? pop es cld mov al, "*" ; Star is not modified in Dos and Windows work: movsb ; copy byte from ds:si to es:di dec di scasb ; check byte at es:di jz jmp_loop ; DI = Al ? inc word calculate_new_size jmp_loop: loopnz work ; repeat if more and not inverted ? dec di ; backup to overwrite inverted ? inc cx ; adjust cx for loop loop work ; repeat if more, exit if not inc di ; adjust dx for exit mov dx, offset come_from mov ah,9 int 21h mov dx,offset go_to int 21h int 20h size_file db: ,20h calculate_new_size db: ,0,0,0,0 come_from db: " * Rod**** *Pem**ber*ton* *!*" ,0Dh,0Ah,24h go_to db: " " ,32,32,32 It just copy Rod Pemberton 0D,0A and $ All is right ! Regards Almas "Rod Pemberton" <do_not_have(a)nohavenot.cmm> a �crit dans le message de news: fts1vu$lpn$1(a)aioe.org... > "almas" <almes(a)naburo.com> wrote in message > news:4801477e$0$868$ba4acef3(a)news.orange.fr... >> I try the code of Rod >> in input i have " Text" in output i have "T e x T " >> Beteewn each letter a space ( 20h) >> > > Ha! Well, I said it was untested... I see that it probably needs "dec > di" > between movsb and scasb. :-( > > > Rod Pemberton >
From: almas on 13 Apr 2008 08:11 Hi every body. .... about the idea of Rod, now, i add bytes I replace the * by Space## I would just add two ## At the end of the text, i have strange thinks. Below : what i have : 1st line the "original" 2nd line what i obtain * Rod**** *Pem**ber*ton* *!* * ## Rod* ##* ##* ##* ## * ##Pem* ##* ##ber*�##ton*'## *�##!*)## i do rod.com > rod.txt mov cx, byte size_file mov si, offset come_from ; 1st file mov di, offset go_to ; the new file push ds ; What do thoose 3 lines ? pop es cld mov al, "*" ; Star is not modified in Dos and Windows work: movsb ; copy byte from ds:si to es:di dec di scasb ; check byte at es:di jz jmp_add ; DI = Al ? inc word calculate_new_size jmp_loop: loopnz work ; repeat if more and not inverted ? dec di ; backup to overwrite inverted ? inc cx ; adjust cx for loop loop work ; repeat if more, exit if not inc di ; adjust dx for exit mov dx, offset come_from mov ah,9 int 21h mov dx,offset go_to int 21h int 20h jmp_add: push cx mov cx,0003 add_it: inc di mov byte [di], "#" inc word calculate_new_size loop add_it pop cx jmp short jmp_loop size_file db: ,20h calculate_new_size db: ,0,0,0,0 come_from db: " * Rod**** *Pem**ber*ton* *!*" ,0Dh,0Ah,24h go_to db: " " ,32,32,32 Regards Almas "Rod Pemberton" <do_not_have(a)nohavenot.cmm> a �crit dans le message de news: fts1vu$lpn$1(a)aioe.org... > "almas" <almes(a)naburo.com> wrote in message > news:4801477e$0$868$ba4acef3(a)news.orange.fr... >> I try the code of Rod >> in input i have " Text" in output i have "T e x T " >> Beteewn each letter a space ( 20h) >> > > Ha! Well, I said it was untested... I see that it probably needs "dec > di" > between movsb and scasb. :-( > > > Rod Pemberton >
From: Rod Pemberton on 13 Apr 2008 11:37 "almas" <almes(a)naburo.com> wrote in message news:4801f23f$0$870$ba4acef3(a)news.orange.fr... > OK : i add dec DI, all ri right ! > Below the code.... but why a push and a pop ? > > mov cx, byte size_file > mov si, offset come_from ; 1st file > mov di, offset go_to ; the new file > > push ds ; What do thoose 3 lines ? > pop es > cld > First two set es equal to ds. es and ds are the segments used by the string instructions. ds should be set to your application by DOS. The third sets the memory direction that the string instructions work: up or down. cld causes them to increment si and di. std causes them to decrement si and di. Rod Pemberton
From: Rod Pemberton on 13 Apr 2008 11:51
"almas" <almes(a)naburo.com> wrote in message news:4802107d$0$874$ba4acef3(a)news.orange.fr... > Hi every body. > > ... about the idea of Rod, now, i add bytes > I replace the * by Space## > I would just add two ## > At the end of the text, i have strange thinks. > > Below : what i have : > > 1st line the "original" > 2nd line what i obtain > > * Rod**** *Pem**ber*ton* *!* > * ## Rod* ##* ##* ##* ## * ##Pem* ##* ##ber*�##ton*'## *�##!*)## > > i do rod.com > rod.txt > > mov cx, byte size_file > mov si, offset come_from ; 1st file > mov di, offset go_to ; the new file > > push ds ; What do thoose 3 lines ? > pop es > cld > mov al, "*" ; Star is not modified in Dos and Windows > > work: > movsb ; copy byte from ds:si to es:di > dec di > scasb ; check byte at es:di > jz jmp_add ; DI = Al ? > inc word calculate_new_size > jmp_loop: > loopnz work ; repeat if more and not inverted ? > dec di ; backup to overwrite inverted ? > inc cx ; adjust cx for loop > loop work ; repeat if more, exit if not > inc di ; adjust dx for exit > > mov dx, offset come_from > mov ah,9 > int 21h > mov dx,offset go_to > int 21h > int 20h > > jmp_add: > push cx > mov cx,0003 > add_it: .... > inc di > mov byte [di], "#" > Are those two reversed? mov byte [di], "#" inc di That will probably output ### for each *. You might want to change this: > jmp_add: > push cx > mov cx,0003 > add_it: > inc di > mov byte [di], "#" > > inc word calculate_new_size > loop add_it > pop cx > jmp short jmp_loop To this: > jmp_add: mov byte [di], " " inc di > push cx mov cx,0002 > add_it: mov byte [di], "#" inc di > > inc word calculate_new_size > loop add_it > pop cx > jmp short jmp_loop I would've done the Space## in the movsb-scasb loop above, probably using string instructions. I have to leave. So, maybe, I'll post later. Rod Pemberton |