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global _char_vga_get_cursor
global _char_vga_set_cursor
global _char_vga_tobios
global _char_vga_frombios
global _char_vga_memread ; NOT A FUNCTION!
global _char_vga_memwrite ; NOT A FUNCTION!
global _char_vga_cursor_x
global _char_vga_cursor_y
global _chv_memread
global _chv_memwrite
_char_vga_cursor_x: dw 0
_char_vga_cursor_y: dw 0
_char_vga_get_cursor:
push bp
mov bp, sp
xor cx, cx ; cx=result
mov dx, 0x3D4
mov al, 0x0E
out dx, al ; read high byte
mov dx, 0x3D5
in al, dx
mov ch, al
mov dx, 0x3D4
mov al, 0x0F
out dx, al ; read low byte
mov dx, 0x3D5
in al, dx
mov cl, al
mov ax, cx ; set return value
mov sp, bp
pop bp
ret
_char_vga_set_cursor:
push bp
mov bp, sp
mov cx, [bp+4] ; cx=argument
mov dx, 0x3D4
mov al, 0x0E
out dx, al ; send high byte
mov dx, 0x3D5
mov al, ch
out dx, al
mov dx, 0x3D4
mov al, 0x0F
out dx, al ; send low byte
mov dx, 0x3D5
mov al, cl
out dx, al
mov sp, bp
pop bp
ret
_char_vga_tobios:
push bp
mov bp, sp
mov cx, bx ; preserve bx
mov ah, 0x0f
int 0x10 ; bh is set by int 0x10, ah=0x0f
mov dl, [_char_vga_cursor_x]
mov dh, [_char_vga_cursor_y]
mov ah, 0x02
int 0x10
mov bx, cx ; restore bx
mov sp, bp
pop bp
ret
_char_vga_frombios:
push bp
mov bp, sp
mov cx, bx ; preserve bx
mov ah, 0x0f
int 0x10 ; bh is set by int 0x10, ah=0x0f
mov [_char_vga_cursor_x], dl
mov [_char_vga_cursor_y], dh
mov ah, 0x03
int 0x10
mov bx, cx ; restore bx
mov sp, bp
pop bp
ret
_char_vga_memread: ; al=result, bx=addr
mov dx, 0xb800
mov fs, dx
mov al, [fs:bx]
ret
_char_vga_memwrite: ; al=value, bx=addr
mov dx, 0xb800
mov fs, dx
mov [fs:bx], al
ret
_chv_memread:
push bp
mov bp,sp
mov bx, [bp+4]
call _char_vga_memread
xor ah, ah
mov sp, bp
pop bp
ret
_chv_memwrite:
push bp
mov bp,sp
mov bx, [bp+4]
mov al, [bp+6]
call _char_vga_memwrite
mov sp, bp
pop bp
ret
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