space invaders

diff --git a/bootcard.asm b/bootcard.asm
index 71e1619..f22c65c 100644 (file)
--- a/bootcard.asm
+++ b/bootcard.asm
@@ -12,7 +12,7 @@ muscur                equ nticks + 4
 spkstat                equ muscur + 4
 vol            equ spkstat + 4
 
-osc_freq       equ 1193182
+OSC_FREQ       equ 1193182
 PIT_DATA0      equ 40h
 PIT_CMD                equ 43h
 PIT_CMD_CHAN0  equ 00h
@@ -60,7 +60,7 @@ KB_CTRL               equ 61h
        mov word [32], timer_intr
        mov word [34], 0
 
-       settimer 0, DIV_ROUND(osc_freq, 100)
+       settimer 0, DIV_ROUND(OSC_FREQ, 100)
 
        mov ax, 13h
        int 10h
@@ -97,15 +97,16 @@ textout:
 .done: ret
 
 timer_intr:
+       pusha
        mov ax, [nticks]
        inc ax
        mov [nticks], ax
 
-       mov bx, [muscur]
+.pmus: mov bx, [muscur]
        shl bx, 2
        mov cx, [music + bx]    ; event time
        cmp cx, 0ffffh
-       jz .off
+       jz .loop
        cmp ax, cx
        jb .dopwm
 
@@ -140,8 +141,14 @@ timer_intr:
 
 .eoi:  mov al, 20h
        out 20h, al     ; EOI
+       popa
        iret
 
+.loop: neg cx
+       mov [muscur], cx
+       jmp .pmus
+       
+
 str1:  db 'message message blah',0
 str2:  db 'Michael & Athina',0