汇编杂谈-光标设置

2023-04-05 2023-04-05 约 239 字预计阅读 1 分钟

调整 CRT 阴极射线管控制器光标位置

调整光标位置

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CRT_ADDR_REG equ 0x3d4
CRT_DATA_REG equ 0x3d5
CRT_CURSOR_HIGH equ 0xe
CRT_CURSOR_LOW equ 0xf

; 每行80个字符，跳转到15行需要设置15*80
mov ax, 15 * 80 
call set_cursor

set_cursor:
	; ax 传递参数
	push bx
	push dx
	mov bx, ax

	mov dx, CRT_ADDR_REG
	mov al, CRT_CURSOR_LOW
	out dx, al

	mov dx, CRT_DATA_REG
	mov al, bl
	out dx, al

	mov dx, CRT_ADDR_REG
	mov al, CRT_CURSOR_HIGH
	out dx, al

	mov dx, CRT_DATA_REG
	mov al, bh
	out dx, al

	pop dx
	pop bx
	ret

获取光标位置

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get_cursor:
	; ax 传递参数
	push bx
	push dx

	mov dx, CRT_ADDR_REG
	mov al, CRT_CURSOR_LOW
	out dx, al

	mov dx, CRT_DATA_REG
	in al, dx
	mov bl, al

	mov dx, CRT_ADDR_REG
	mov al, CRT_CURSOR_HIGH
	out dx, al

	mov dx, CRT_DATA_REG
	in al, dx
	mov bh, al

	mov ax, bx
	pop dx
	pop bx
	ret