rnd

[bootcard] / bootcard.asm

diff --git a/bootcard.asm b/bootcard.asm
index ddf50cd..4a2f3e4 100644 (file)
--- a/bootcard.asm
+++ b/bootcard.asm
@@ -8,7 +8,8 @@
 
 nticks equ 7e00h
 tmoffs equ 7e04h
-muscur equ 7e08h
+musptr equ 7e08h
+ppos   equ 7e0ch
 
 %macro setcur 2
        mov dx, %1 | (%2 << 8)
@@ -42,7 +43,7 @@ start:        xor ax, ax
        mov sp, 7c00h
 
        mov di, nticks
-       mov cx, 6
+       mov cx, 8
        rep stosw
 
        mov word [32], tintr
@@ -75,6 +76,8 @@ mainloop:
 
        call drawbg
 
+       call psys
+
        jmp mainloop
 
 drawbg:
@@ -115,6 +118,28 @@ drawbg:
        
        ret
 
+psys:  cmp word [ppos + 2], 0
+       ja .skipspawn
+
+       call rnd
+       add ax, 128
+       mov [ppos + 2], ax
+       call rnd
+       add ax, 32
+       mov [ppos], ax
+.skipspawn:
+       dec word [ppos + 2]
+       mov ax, [ppos + 2]
+       shr ax, 2
+       imul bx, ax, 320
+       add bx, [ppos]
+       mov byte [es:bx], 0eh
+
+rnd:   in al, 40h
+       mov ah, al
+       in al, 40h
+       shr ax, 8
+       ret
 
 textout:
        mov al, [si]
@@ -129,24 +154,26 @@ textout:
 
 tintr:
        pusha
-       push ds
-       push word 0
-       pop ds
        mov ax, [nticks]
        inc ax
        mov [nticks], ax
 
+       mov bx, [musptr]
+       cmp bx, 23*3
+       jnz .skiploop
+       xor bx, bx
+       mov [tmoffs], ax
+.skiploop:
+       xor cx, cx
+       mov cl, [music + bx]
+       shl cx, 4
        sub ax, [tmoffs]
-.pmus: mov bx, [muscur]
-       shl bx, 2
-       mov cx, [music + bx]
-       cmp cx, 0ffffh
-       jz .loop
        cmp ax, cx
        jb .eoi
 
-       inc word [muscur]
-       mov ax, [music + 2 + bx]
+       mov ax, [music + 1 + bx]
+       add bx, 3
+       mov [musptr], bx
        test ax, ax
        jz .off
        mov bx, ax
@@ -158,51 +185,16 @@ tintr:
 
 .eoi:  mov al, 20h
        out 20h, al
-       pop ds
        popa
        iret
 
-.loop: neg cx
-       mov [muscur], cx
-       mov ax, [nticks]
-       mov [tmoffs], ax
-       jmp .pmus
-       
-
 str1:  db 'message blah',0
 str2:  db 'Michael & Athena',0
 
-G2     equ 12175
-C3     equ 9121
-D3     equ 8126
-B2     equ 9664
-F3     equ 6833
-E3     equ 7239
-
-music: dw 0,           0
-       dw 40,          G2
-       dw 200,         C3
-       dw 320,         C3
-       dw 360,         C3
-       dw 600,         0
-       dw 680,         G2
-       dw 840,         D3
-       dw 960,         B2
-       dw 1000,        C3
-       dw 1240,        0
-       dw 1320,        G2
-       dw 1480,        C3
-       dw 1600,        F3
-       dw 1640,        F3
-       dw 1800,        E3
-       dw 1920,        D3
-       dw 1960,        C3
-       dw 2120,        B2
-       dw 2240,        C3
-       dw 2280,        D3
-       dw 2600,        0
-       dw 2760,        0
-       dw 0ffffh,      0
+music: dd 0a2f8f00h, 0a11123a1h, 23a11423h, 28000023h, 0be322f8fh, 25c0391fh
+       dd 4b23a13ch, 8f500000h, 23a15a2fh, 641ab161h, 476e1ab1h, 1fbe751ch
+       dd 8223a178h, 0a18925c0h, 1fbe8c23h, 0aa0000a0h
+       dw 0
 
 w5:    dw 5
 w30:   dw 30