X-Git-Url: http://git.dujemihanovic.xyz/posts?a=blobdiff_plain;f=print.s;h=3a46c724efa996310ab365d46c3c6f5330e47fb2;hb=eec791adfbaddde2f5724e0f5c7319e7d2aaef0e;hp=ab6eef4c92c9a66441c0abd6c1999ddc61af5bd3;hpb=f9f4f8ebffb463d53ae5a239ddfbe8380f258b8b;p=nameless-os.git

diff --git a/print.s b/print.s
index ab6eef4..3a46c72 100644
--- a/print.s
+++ b/print.s
@@ -1,12 +1,41 @@
 %define CURRENT_ADDR cs:di
 
-print_word:
+; Prints a null terminated string of your choice.
+; Arguments:
+;     CS:DI - pointer to the string you want to print
+;     BL - 0 prints newline, otherwise no
+print
+	pusha
+	mov ah, 0Eh ; teletype print
+.write2
+	mov al, [CURRENT_ADDR] ; get current char and put it in al
+	cmp al, 0 ; check if al is null (string terminator)
+	je .newline ; if it is, start a new line
+	int 10h ; otherwise write the char
+	inc di ; increment pointer to string
+	jmp .write2 ; jump back to this section
+.newline
+	cmp bl, 1
+	je .done
+	mov al, 0Dh ; carriage return
+	int 10h
+	mov al, 0Ah ; line feed
+	int 10h
+.done
+	popa
+	ret ; return
+
+; Prints a word (16-bit value) in hex format.
+; Arguments:
+;     DX - word to print
+;     BL - 0 will print a newline, 1 won't
+print_word
 	pusha ; push all regs to stack
 	mov di, HEX_OUT+5 ; set destination index to last char in HEX_OUT
 	mov ax, dx ; copy argument to accumulator
 	and al, 00001111b ; extract the low nibble of the low half of the accumulator
 	call .compare ; fill in the string with correct value
-	dec di ; decrement destination index
+	dec di ; decrement string pointer
 	mov ax, dx ; copy argument to accumulator
 	and al, 11110000b ; extract high nibble of low half of accumulator
 	shr al, 4 ; shift high nibble to low nibble
@@ -20,102 +49,88 @@ print_word:
 	and al, 11110000b
 	shr al, 4
 	call .compare
-	jmp .write ; write string
-
-.write:
-	popa ; get back our arguments
-	mov dl, cl ; column
-	mov dh, ch ; row
-	pusha ; save registers
-	mov al, 1 ; update cursor
-	mov bh, 0 ; page number
-	mov bl, 00000111b ; colors
-	mov cx, 6 ; length of string
-	push cs ; push code segment address
-	pop es ; pop to extra segment address
-	mov bp, HEX_OUT ; offset to extra segment of string
-	mov ah, 13h ; write string
-	int 10h ; BIOS interrupt
+	mov di, HEX_OUT
+	call print ; write string
 	popa
-	ret ; return
+	ret
 
-.compare:
+.compare
 	cmp al, 0 ; compare al with 0
 	jne .one ; if not equal, compare with 1
 	mov byte [CURRENT_ADDR], '0' ; set character to ASCII 0
 	ret ; return
-.one:
+.one
 	cmp al, 1
 	jne .two
 	mov byte [CURRENT_ADDR], '1'
 	ret
-.two:
+.two
 	cmp al, 2
 	jne .three
 	mov byte [CURRENT_ADDR], '2'
 	ret
-.three:
+.three
 	cmp al, 3
 	jne .four
 	mov byte [CURRENT_ADDR], '3'
 	ret
-.four:
+.four
 	cmp al, 4
 	jne .five
 	mov byte [CURRENT_ADDR], '4'
 	ret
-.five:
+.five
 	cmp al, 5
 	jne .six
 	mov byte [CURRENT_ADDR], '5'
 	ret
-.six:
+.six
 	cmp al, 6
 	jne .seven
 	mov byte [CURRENT_ADDR], '6'
 	ret
-.seven:
+.seven
 	cmp al, 7
 	jne .eight
 	mov byte [CURRENT_ADDR], '7'
 	ret
-.eight:
+.eight
 	cmp al, 8
 	jne .nine
 	mov byte [CURRENT_ADDR], '8'
 	ret
-.nine:
+.nine
 	cmp al, 9
 	jne .ten
 	mov byte [CURRENT_ADDR], '9'
 	ret
-.ten:
+.ten
 	cmp al, 0Ah
 	jne .eleven
 	mov byte [CURRENT_ADDR], 'A'
 	ret
-.eleven:
+.eleven
 	cmp al, 0Bh
 	jne .twelve
 	mov byte [CURRENT_ADDR], 'B'
 	ret
-.twelve:
+.twelve
 	cmp al, 0Ch
 	jne .thirteen
 	mov byte [CURRENT_ADDR], 'C'
 	ret
-.thirteen:
+.thirteen
 	cmp al, 0Dh
 	jne .fourteen
 	mov byte [CURRENT_ADDR], 'D'
 	ret
-.fourteen:
+.fourteen
 	cmp al, 0Eh
 	jne .fifteen
 	mov byte [CURRENT_ADDR], 'E'
 	ret
-.fifteen:
+.fifteen
 	mov byte [CURRENT_ADDR], 'F'
 	ret
 
-HEX_OUT: db "0x0000"
+HEX_OUT db "0x0000", 0