fix flickering

[lifeboot.git] / lifeboot.asm

diff --git a/lifeboot.asm b/lifeboot.asm
index 658abe719824f5cc7a97dc2af2ec281ec469289c..655febbd6ab1d07658e013e5705f4455a728dd6f 100644 (file)
--- a/lifeboot.asm
+++ b/lifeboot.asm
@@ -14,7 +14,7 @@ org 0x7c00
 
 %define COLS 80
 %define ROWS 25
 
 %define COLS 80
 %define ROWS 25

-%define VGAPGSZ (COLS * ROWS * 2)
+%define VGAPGSZ (COLS * ROWS * 2 + 96)  ; why 96 ??????

 
 ; memory layout ---------------------------------------------------------------
 
 
 ; memory layout ---------------------------------------------------------------
 


@@ -52,12 +52,19 @@ mov ah, 0x01                ; set text-mode cursor shape
 int 0x10                    ; video services
 
 ; initialize xss
 int 0x10                    ; video services
 
 ; initialize xss

+
+set_xss_seed:
+

 mov ah, 0x00                ; get
 int 0x1a                    ;  system time
 mov ah, 0x00                ; get
 int 0x1a                    ;  system time

+
+cmp dx, 0
+je set_xss_seed             ; if seed is 0, xs wont work properly
+

 mov [xss], dx               ; cx:dx = number of clock ticks since midnight
 
 ; initialize currvgapg
 mov [xss], dx               ; cx:dx = number of clock ticks since midnight
 
 ; initialize currvgapg

-mov word [currvgapg], VGAPGSZ
+mov word [currvgapg], 0

 
 ; start simulation from random state ------------------------------------------
 
 
 ; start simulation from random state ------------------------------------------
 


@@ -69,10 +76,10 @@ call init_grid
 
 next_state:
 
 
 next_state:
 

-call flip_vga_page          ; display current state
-call delay                  ; sleep a little
-
-call write_next_vga_page    ; write the next state to the hidden page
+call vsync_wait
+call write_next_vga_page
+call wait_keypress
+call flip_vga_page

 
 jmp next_state
 
 
 jmp next_state
 


@@ -94,6 +101,17 @@ int 0x15                    ; wait
 
 ret
 
 
 ret
 

+; wait_keypress() - wait for any keypress -------------------------------------
+
+; clobbers: ax
+
+wait_keypress:
+
+mov ah, 0x00        ; read key press
+int 0x16            ; keyboard services
+
+ret
+

 ; vsync_wait() - wait for display to enter the next VBlank cycle --------------
 
 ; clobbers ax, dx
 ; vsync_wait() - wait for display to enter the next VBlank cycle --------------
 
 ; clobbers ax, dx


@@ -248,7 +266,7 @@ mov byte [bp - 4], -1       ; i = -1
 
         mov dx, [es:si + bx]            ; dl = cell state
 
 
         mov dx, [es:si + bx]            ; dl = cell state
 

-        test dl, ALIVE                  ; if (!ALIVE) continue
+        cmp dl, ALIVE                   ; if (!ALIVE) continue

         jne .continue
 
         inc byte [bp - 3]               ; neighbours++
         jne .continue
 
         inc byte [bp - 3]               ; neighbours++


@@ -288,20 +306,20 @@ shl bx, 1
 
 mov dx, [es:si + bx]        ; dl = cell current state
 
 
 mov dx, [es:si + bx]        ; dl = cell current state
 

-test dl, ALIVE              ; if (ALIVE) {
+cmp dl, ALIVE               ; if (ALIVE) {

 jne .else
 
 jne .else
 

-test ax, 2                  ;     if (n < 2)
+cmp ax, 2                   ;     if (n < 2)

 jl .dead                    ;         return DEAD
 
 jl .dead                    ;         return DEAD
 

-test ax, 3                  ;     if (n > 3)
+cmp ax, 3                   ;     if (n > 3)

 jg .dead                    ;         return DEAD
 
 jmp .alive                  ;     return ALIVE
 
 .else:                      ; }
 
 jg .dead                    ;         return DEAD
 
 jmp .alive                  ;     return ALIVE
 
 .else:                      ; }
 

-test ax, 3                  ; if (n != 3)
+cmp ax, 3                   ; if (n != 3)

 jne .dead                   ;     return DEAD
 
 .alive:                     ; return ALIVE
 jne .dead                   ;     return DEAD
 
 .alive:                     ; return ALIVE


@@ -333,7 +351,7 @@ xor cx, cx                  ; i = 0
 call write_next_cell_state
 
 inc cx
 call write_next_cell_state
 
 inc cx

-test cx, COLS * ROWS
+cmp cx, COLS * ROWS

 jl .update_loop             ; for i in [0 .. COLS * ROWS - 1]
 
 ret
 jl .update_loop             ; for i in [0 .. COLS * ROWS - 1]
 
 ret