cleanup

[lifeboot.git] / lifeboot.asm

diff --git a/lifeboot.asm b/lifeboot.asm
index ed033500fa6fd5b529a420c2dd764442c6607d13..8f11b8700d7a9e04ffcb69e53f40962a118375bb 100644 (file)
--- a/lifeboot.asm
+++ b/lifeboot.asm
@@ -1,25 +1,27 @@
 bits 16
-org 0x7c00
+org 7c00h
 
 ; =============================================================================
 
 ; settings --------------------------------------------------------------------
 
 %define DEAD ' '            ; char to represent a dead cell
-%define ALIVE '#'           ; char to represent an alive cell
-%define PRINT_COLOR 0x07    ; grey on black
-%define WAIT_DELAY 0x02     ; 0.131072 seconds
+%define ALIVE '.'           ; char to represent an alive cell
+%define PRINT_COLOR 07h     ; grey on black
+
+%define WAIT_DELAY_CX 01h   ; cx:dx = delay in microseconds
+%define WAIT_DELAY_DX 00h
 
 ; constants -------------------------------------------------------------------
 
 %define COLS 80
 %define ROWS 25
-%define VGAPGSZ (COLS * ROWS * 2 + 96)  ; why 96 ??????
+%define VGAPGSZ 1000h
 
 ; memory layout ---------------------------------------------------------------
 
-%define ORG 0x7c00
-%define VGA 0xb8000
+%define ORG 7c00h
+%define VGA 0b8000h
 %define DAT ORG + 512
 
 ; static variables ------------------------------------------------------------
@@ -47,13 +49,20 @@ mov sp, bp
 cld
 
 ; disable cursor
-mov ch, 0x3f                ; cursor start and options
-mov ah, 0x01                ; set text-mode cursor shape
-int 0x10                    ; video services
+mov ch, 3fh                 ; cursor start and options
+mov ah, 01h                 ; set text-mode cursor shape
+int 10h                     ; video services
 
 ; initialize xss
-mov ah, 0x00                ; get
-int 0x1a                    ;  system time
+
+set_xss_seed:
+
+mov ah, 00h                 ; get
+int 1ah                     ;  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
@@ -69,8 +78,9 @@ call init_grid
 
 next_state:
 
+call vsync_wait
 call write_next_vga_page
-call wait_keypress
+call delay
 call flip_vga_page
 
 jmp next_state
@@ -85,22 +95,11 @@ jmp next_state
 
 delay:
 
-mov cx, WAIT_DELAY          ; cx:dx = interval in microseconds
-mov dx, 0
-
-mov ah, 0x86
-int 0x15                    ; wait
-
-ret
-
-; wait_keypress() - wait for any keypress -------------------------------------
-
-; clobbers: ax
-
-wait_keypress:
+mov cx, WAIT_DELAY_CX
+mov dx, WAIT_DELAY_DX
 
-mov ah, 0x00        ; read key press
-int 0x16            ; keyboard services
+mov ah, 86h
+int 15h                     ; wait
 
 ret
 
@@ -110,16 +109,16 @@ ret
 
 vsync_wait:
 
-mov dx, 0x3da               ; input status #1 register
+mov dx, 3dah                ; input status #1 register
 
 .wait_on:
     in al, dx
-    test al, 0x08           ; vertical retrace bit
+    test al, 08h            ; vertical retrace bit
     jnz .wait_on
 
 .wait_off:
     in al, dx
-    test al, 0x08
+    test al, 08h
     jz .wait_off
 
 ret
@@ -187,20 +186,8 @@ call vsync_wait
 xor word [currvgapg], VGAPGSZ   ; flip currvgapg
 setnz al                        ; al = !(currvgapg == 0)
 
-mov di, [currvgapg]             ; es:di -> current page
-mov dh, PRINT_COLOR
-
-mov dl, 'P'
-mov [es:di], dx
-
-mov dl, al
-add dl, 48
-add di, 2
-
-mov [es:di], dx
-
-mov ah, 0x05                ; select active display page
-int 0x10                    ; video services
+mov ah, 05h                 ; select active display page
+int 10h                     ; video services
 
 ret
 
@@ -371,4 +358,4 @@ jmp halt
 ; =============================================================================
 
 times 510 - ($ - $$) db 0   ; fill remaining bytes with zeroes
-dw 0xaa55                   ; mbr magic byte
+dw 0aa55h                   ; mbr magic byte