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Draw clock hands

This commit is contained in:
Juhani Krekelä 2022-03-11 21:07:46 +02:00
parent 5dcc4553cc
commit 70e6513b76
1 changed files with 88 additions and 27 deletions
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115
dosclock.asm
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@ -2,6 +2,15 @@ org 0x100
cpu 8086 cpu 8086
bits 16 bits 16
midpoint_x equ 160
midpoint_y equ 100
hour_hand_len equ 50
hour_hand_color equ 7
minute_hand_len equ 80
minute_hand_color equ 7
second_hand_len equ 75
second_hand_color equ 4
section .code section .code
setup: setup:
@ -51,33 +60,52 @@ mainloop:
mov [minute], cl mov [minute], cl
mov [second], dh mov [second], dh
mov word [line_sx], 80 mov ax, [hour]
mov word [line_sy], 0
mov word [line_ex], 60
mov ax, [second]
mov [line_ey], ax
call draw_line
mov word [line_sx], 80 ; 12 hour clock face → map 12…23 to 0…11
mov word [line_sy], 60 cmp ax, 12
mov word [line_ex], 60 je .under_12
mov ax, [second] sub ax, 12
mov [line_ey], ax .under_12:
call draw_line
mov word [line_sx], 80 ; 1 hour = 30° rotation of hour hand
mov word [line_sy], 0 mul word [thirty]
mov word [line_ex], 20 mov bx, ax
mov ax, [second]
mov [line_ey], ax
call draw_line
mov word [line_sx], 80 ; 2 minutes = 1° rotation of hour hand
mov word [line_sy], 60 mov ax, [minute]
mov word [line_ex], 20 shr ax, 1
add bx, ax
; Draw hour hand
mov ax, hour_hand_len
mov cl, hour_hand_color
call draw_hand
; 1 minute = 5° rotation of minute hand
mov ax, [minute]
mul word [six]
mov bx, ax
; 12 seconds = 1° rotation of minute hand
mov ax, [second] mov ax, [second]
mov [line_ey], ax div word [twelve]
call draw_line add bx, ax
; Draw minute hand
mov ax, minute_hand_len
mov cl, minute_hand_color
call draw_hand
; 1 second = 5° rotation of second hand
mov ax, [second]
mul word [six]
mov bx, ax
; Draw second hand
mov ax, second_hand_len
mov cl, second_hand_color
call draw_hand
.unchanged: .unchanged:
hlt hlt
@ -104,9 +132,40 @@ clear_screen:
pop bp pop bp
ret ret
; in:
; ax = hand length
; bx = hand angle
; cl = hand color
draw_hand:
push ax
push bx
push dx
mov word [line_sx], midpoint_x
mov word [line_sy], midpoint_y
mov word [line_ex], midpoint_x
mov word [line_ey], midpoint_y
mov dx, ax
call sinx
add [line_ex], ax
mov ax, dx
call cosx
sub [line_ey], ax
mov bl, cl
call draw_line
pop dx
pop bx
pop ax
ret
; in: ; in:
; [line_sx], [line_sy] = starting point ; [line_sx], [line_sy] = starting point
; [line_ex], [line_ey] = ending point ; [line_ex], [line_ey] = ending point
; bl = color
; clobbers: ; clobbers:
; [line_sx], [line_sy], [line_ex], [line_ey] ; [line_sx], [line_sy], [line_ex], [line_ey]
draw_line: draw_line:
@ -165,7 +224,7 @@ draw_line_low:
xor dx, dx xor dx, dx
sub dx, [width] sub dx, [width]
.y_adjust_done .y_adjust_done:
; errorterm = 2·dy - dx ; errorterm = 2·dy - dx
mov ax, [line_dy] mov ax, [line_dy]
@ -177,7 +236,7 @@ draw_line_low:
jz draw_line_end jz draw_line_end
.loop: .loop:
mov byte [es:bp], 7 mov byte [es:bp], bl
cmp ax, 0 cmp ax, 0
jle .no_y_adjust jle .no_y_adjust
@ -219,7 +278,7 @@ draw_line_high:
mov [line_dx], ax mov [line_dx], ax
mov dx, -1 mov dx, -1
.x_adjust_done .x_adjust_done:
; errorterm = 2·dx - dy ; errorterm = 2·dx - dy
mov ax, [line_dx] mov ax, [line_dx]
@ -231,7 +290,7 @@ draw_line_high:
jz draw_line_end jz draw_line_end
.loop: .loop:
mov byte [es:bp], 7 mov byte [es:bp], bl
cmp ax, 0 cmp ax, 0
jle .no_x_adjust jle .no_x_adjust
@ -448,6 +507,8 @@ sin_table:
dw 65526 ; sin(89°) dw 65526 ; sin(89°)
six dw 6 six dw 6
thirty dw 30
twelve dw 12
section .data section .data
hour dw 0 hour dw 0