Assembly: Print string code with BIOS interrupts won't work

[SIGSEGV]

Printing one character works perfectly fine, but trying to make it loop through a word doesn't...

;the actual codesection .textglobal StartStart:     	MOV AX, 0x7C0          ;set ax to 112, this is where the BIOS puts us so start there, 0x7c0=112	MOV SI, welcome	CALL _PRNTSTR	MOV AL, 'X'	CALL _PRNTCHR	MOV AL, 'D'	CALL _PRNTCHR	JMP $ 		;Infinite loop, hang it here._PRNTCHR:			;_PRNTCHR function: Prints the character in register AL	MOV AH, DRAW_TEXT	;Tell BIOS that we need to print one character on screen.	MOV BH, 0x00		;Page no. We're not gonna be double buffering so just keep this as 0	MOV BL, 0x07		;Text attribute 0x07 is lightgrey font on black background	INT VIDEO_INTERRUPT	;Call video interrupt	RET			;Return to calling procedure_PRNTSTR:	PrintCharacterInString:		MOV AL, [SI]	;Get a byte from string and store in AL register		INC SI		;Increment SI pointer		OR AL, AL	;Check if value in AL is zero (end of string)		JZ _EXIT 	;If end then return		CALL _PRNTCHR		JMP PrintCharacterInString	_EXIT:	RETTIMES 510 - ($ - $$) db 0	;Fill the rest of sector with 0DW 0xAA55			;Add boot signature at the end of bootloader;storing stuffsection .dataDRAW_TEXT equ 0x0EVIDEO_INTERRUPT equ 0x10welcome db 'TEST', 0

[manikyath]

about half way trough the entire thing turns into a comment string, i'm guessing thats an issue with the code tag, and is not actually the case in your IDE?

 

other than that, my assembly knowledge is a tad rusty, and i cant really spot any flaws...

[SIGSEGV]

about half way trough the entire thing turns into a comment string, i'm guessing thats an issue with the code tag, and is not actually the case in your IDE?

 

other than that, my assembly knowledge is a tad rusty, and i cant really spot any flaws...

Yeah, the code tag does that when it sees the apostrophe in one of my comments

[SIGSEGV]

You forgot to update your data segment register to the current one. I've modified a few things on your code to make it work

 

;the actual codesection .textglobal StartStart:    	MOV AX, 0x7C0          ;set ax to 112, this is where the BIOS puts us so start there, 0x7c0=112	MOV BX, welcome	MOV DS, AX	POP SI	CALL _PRNTSTR	MOV AL, 'X'	CALL _PRNTCHR	MOV AL, 'D'	CALL _PRNTCHR	JMP $   ;Infinite loop, hang it here._PRNTSTR:	MOV AL, byte[BX]  ;Get a byte from string and store in AL register	INC BX   	  ;Increment BX pointer	OR AL, AL   ;Check if value in AL is zero (end of string) 	JZ   _EXIT	PUSH BX	CALL _PRNTCHR     ;If end then return	POP BX	JMP _PRNTSTR_PRNTCHR:        ;_PRNTCHR function: Prints the character in register AL	MOV AH, DRAW_TEXT ;Tell BIOS that we need to print one character on screen.	MOV BX, 0x0007  ;Page no. We're not gonna be double buffering so just keep this as 0                 	;Text attribute 0x07 is lightgrey font on black background	INT VIDEO_INTERRUPT ;Call video interrupt               ;Return to calling procedure_EXIT:RET;storing stuffsection .dataDRAW_TEXT equ 0x0EVIDEO_INTERRUPT equ 0x10welcome db 'TEST', 0

Thanks it works now