mirror of https://github.com/nmlgc/ReC98.git
69 lines
1.3 KiB
NASM
69 lines
1.3 KiB
NASM
; Assuming that the CDG image in the given [slot] was previously displayed
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; centered at (⌊x_center/8⌋*8, y_center), this function clears the two lines
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; at the bottom of that image, as well as the one line immediately below, from
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; the VRAM's E plane.
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; void cdg_unput_for_upwards_motion_e(int x_center, int y_center, int slot);
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public CDG_UNPUT_FOR_UPWARDS_MOTION_E
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cdg_unput_for_upwards_motion_e proc near
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@@h = word ptr -4
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@@w = word ptr -2
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@@slot = word ptr 4
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@@y_center = word ptr 6
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@@x_center = word ptr 8
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enter 4, 0
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push si
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push di
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mov bx, [bp+@@slot]
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shl bx, 4
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mov ax, _cdg_slots.pixel_width[bx]
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mov [bp+@@w], ax
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mov bx, [bp+@@slot]
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shl bx, 4
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mov ax, _cdg_slots.pixel_height[bx]
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mov [bp+@@h], ax
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mov ax, [bp+@@w]
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cwd
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sub ax, dx
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sar ax, 1
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sub [bp+@@x_center], ax
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mov ax, [bp+@@h]
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cwd
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sub ax, dx
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sar ax, 1
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add ax, -2
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add [bp+@@y_center], ax
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mov ax, [bp+@@x_center]
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sar ax, 3
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mov dx, [bp+@@y_center]
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shl dx, 6
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add ax, dx
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mov dx, [bp+@@y_center]
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shl dx, 4
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add ax, dx
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mov di, ax
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mov ax, 0E000h
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mov es, ax
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assume es:nothing
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mov dx, [bp+@@w]
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shr dx, 4
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mov si, (640 / 8)
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sub si, dx
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sub si, dx
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xor ax, ax
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mov cx, dx
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rep stosw
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add di, si
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mov cx, dx
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rep stosw
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add di, si
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mov cx, dx
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rep stosw
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pop di
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pop si
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leave
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retn 6
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cdg_unput_for_upwards_motion_e endp
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