ReC98/th04/main/scroll_y_1.asm

25 lines
369 B
NASM

public SCROLL_SUBPIXEL_Y_TO_VRAM_SEG1
scroll_subpixel_y_to_vram_seg1 proc near
arg_bx near, @sy:word
mov ax, @sy
sar ax, 4
cmp _scroll_active, 0
jz short @@lt0?
add ax, _scroll_line
@@lt0?:
or ax, ax
jge short @@lt400?
add ax, RES_Y
jmp short @@ret
@@lt400?:
cmp ax, RES_Y
jl short @@ret
sub ax, RES_Y
@@ret:
ret_bx
scroll_subpixel_y_to_vram_seg1 endp