1 files changed, 115 insertions, 0 deletions
diff --git a/xxx/boot2/print_string_16.asm b/xxx/boot2/print_string_16.asm
new file mode 100644
index 0000000..9f81a87
--- /dev/null
+++ b/xxx/boot2/print_string_16.asm
@@ -0,0 +1,115 @@
+[bits 16]
+
+BLANK:
+    db 0x12
+
+SPACE:
+    db " ",0
+
+;print_string routine ([bx])
+;this routine will print a null terminated string at [bx] to the screen.
+print_string:
+
+    pusha			;push all registers
+    mov ah,0x0e
+
+    print_string_loop:
+
+	;check if value at [bx] is "\0" (end of string)
+	mov cl,[bx]
+	cmp cl,0
+	je print_string_finish
+
+	;otherwise instruct BIOS to print the current char
+	mov al,cl
+	int 0x10
+
+	;proceed with next char
+        inc bx
+	jmp print_string_loop
+
+    print_string_finish:
+
+    popa			;pop all registers
+    ret				;return to caller
+
+print_clear:
+
+pusha
+    mov ah,0x6	    ;func
+    mov al,0	    ;scroll one line
+    mov bh,[BLANK]  ;blank char
+
+    mov ch,0	    ;upper left corner
+    mov cl,0
+    mov dh,20	    ;lower right corner
+    mov dl,40
+    int 0x10
+
+    mov ah,0x2
+    mov bh,0
+    mov dl,0
+    mov dh,20
+    int 0x10
+popa
+
+print_nextline:
+
+    pusha
+
+    mov ah,0x6	    ;func
+    mov al,1	    ;scroll one line
+    mov bh,[BLANK]  ;blank char
+
+    mov ch,0	    ;upper left corner
+    mov cl,0
+    mov dh,20	    ;lower right corner
+    mov dl,40
+    int 0x10
+
+
+    mov ah,0x3
+    mov bh,0
+    int 0x10
+
+
+    mov ah,0x2
+    mov dl,0
+    int 0x10
+
+    mov bx,SPACE
+    call print_string
+
+    popa
+    ret
+
+
+;print byte from al to screen
+ print_hex_byte: 
+
+ pusha
+
+   mov [.temp],al
+   shr al,4
+   cmp al,10
+   sbb al,69h
+   das
+ 
+   mov ah,0Eh
+   int 10h
+ 
+   mov al,[.temp]
+   ror al,4
+   shr al,4
+   cmp al,10
+   sbb al,69h
+   das
+ 
+   mov ah,0Eh
+   int 10h
+
+popa
+ 
+   ret
+ 
+ .temp db 0