Rectangular Concentric Spiral Ring

D_seg segment
Row_u db 0; boundary above the row-> r
Row_d dB 25; boundary below the row-> L
Col_l db 0; boundary on the left of the column-> U
Col_r dB 80; boundary on the right of the column-> d
End_flag db 0; 1 indicates end, 0 indicates continue
Direction direct dB 'R'; current forward direction, initially to the right
D_seg ends
;
Code segment
Assume Cs: code, DS: d_seg
Start:
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Main program segment code
Main proc far
PUSH DS
XOR ax, ax
PUSH AX
;
MoV ax, d_seg
MoV ds, ax
;
Call clear; clear screen
;
MoV dx, 0; 0 rows and 0 columns with Cursor
MoV BH, 0
MoV ah, 2
Int 10 h
;
Call drawdirect; output image
; Press any key to exit
Magain:
MoV ah, 7
Int 21 h
CMP Al, 'Q'
Je mexit
JMP magain
Mexit:
Call clear
RET
Main endp
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; Drawing direction control
Drawdirect proc near
D_continue:
; Compared with col_l, if col_l> = DL, then explain direct = 'U'
CMP export direct, 'L'; whether it is left
Jnz no_left; no
Coll_next:
Call char_disp; output character
Dec dl; move one column to the left
CMP col_l, DL; compare whether this direction is used
Jl coll_next; no need to switch, continue output
INC dl; roll back a column to the right
INC col_l; add one to the left boundary
INC col_l
MoV ready direct, 'U'; turn to upward
Jmp dcmp; exit
;
No_left:
; Compared with col_r, if col_r <= DL, then sort direct = 'D'
CMP export direct, 'R'; whether it is the right side
Jnz no_right; no
Colr_next:
Call char_disp; output character
INC dl; move one column to the right
CMP col_r, DL; compare whether this direction is to be switched
JG colr_next; no need to switch, continue to output
Dec dl; roll back one column to the left
Dec col_r; minus one on the right boundary
Dec col_r
MoV forward direct, 'd; turn downward
Jmp dcmp; exit
;
No_right:
; Compared with row_u, if row_u> = DH, then dircet = 'R'
CMP forward direct, 'U'; indicates whether to go up
Jnz no_up; no
Rowu_next:
Call char_disp; output character
Dec DH; move up a row
CMP row_u, DH; compare whether the direction has been changed
Jl rowu_next; no need to switch, continue output
Inc dh; roll back a row
INC row_u; add one on the upper boundary
; INC row_u
MoV ready direct, 'R'; turn to the right
Jmp dcmp; exit
;
No_up:
; Compared with row_d, if row_d <= DH, then direction direct = 'l'
Rowd_next:
Call char_disp
Inc dh; move down a row
CMP row_d, DH; compare whether the direction is changed
JG rowd_next; no need to switch, continue output
Dec DH; roll back a row
Dec row_d; lower boundary minus one
; Dec row_d
MoV ready direct, 'L'; turn to left
DCMP:
Push ax; save al
MoV Al, row_u
INC al; add one on the upper boundary
CMP Al, row_d; whether the upper boundary is coincident with the lower boundary
Pop ax; restore al
Jge d_exit; exit if it is to overlap
Push ax; save al
MoV Al, col_l
INC al; add one on the left border
CMP Al, col_r; exit if it is to overlap
Pop ax; restore al
Jge d_exit; exit if it is to overlap
JMP d_continue; then output
D_exit:
RET
Drawdirect endp
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Char_disp proc near
Push CX; save CX
;
MoV ah, 2
MoV BH, 0; 0 page display
Int 10 h; cursor position
;
MoV Al, 2; placement of smiley ASCII code
MoV BL, 07; black and white characters
MoV CX, 1; output character 1
MoV ah, 9
Int 10 h; Output smiling face
Pop CX
RET
Char_disp endp
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Clear proc near
MoV ax, 0600 h; full screen Blank
MoV BH, 7; normal display
Sub CX, CX; Start Point (0, 0)
MoV dx, 184fh; endpoint (24, 79)
Int 10 h
RET
Clear endp
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Code ends
End start