Lynx changes by Karri Kaksonen.

[cc65] / libsrc / lynx / lynx-160-102-16.s

diff --git a/libsrc/lynx/lynx-160-102-16.s b/libsrc/lynx/lynx-160-102-16.s
index 7825e2d8e53b57b0a1896b81344ab7d6f22c0146..f37723df9e1aaa1ca2178876a406e6f1efcb2fa6 100644 (file)
--- a/libsrc/lynx/lynx-160-102-16.s
+++ b/libsrc/lynx/lynx-160-102-16.s
@@ -240,10 +240,11 @@ GETERROR:
 ;
 ; To set the frame rate for the display hardware call tgi_ioctl(3, rate)
 ;
-; To make a request for swapping the display buffers call tgi_ioctl(4, dataptr)
-; If the value of the char pointed to by the dataptr is 0 then fill in the
-; value of the char with the current state of the swap buffer 0 = idle, 1 = busy
-; If the value is not 0 then activate the swap function at next VBL interrupt
+; To check if the drawing engine is busy with the previous swap you can
+; call tgi_ioctl(4, 0). It returns 0 if idle and 1 if busy
+;
+; To update displays you can call tgi_ioctl(4, 1) it will wait for the
+; next VBL interrupt and swap draw and view buffers.
 ;
 ; Set an address for a subroutine you want to call at every VBL
 ; tgi_ioctl(5, hook)
@@ -468,9 +469,9 @@ IRQ:
         bne    IRQVBL
        clc                     ; Not a VBL interrupt - exit
        rts
-IRQVBL: sta    INTRST          ; Clear interrupt
+IRQVBL: 
        lda     SWAPREQUEST
-       bne     @L0
+       beq     @L0
        lda     DRAWPAGE
        jsr     SETVIEWPAGE
        lda     DRAWPAGE
@@ -480,7 +481,7 @@ IRQVBL: sta INTRST          ; Clear interrupt
        stz     SWAPREQUEST
 @L0:
        jsr     VBLHOOK
-       sec
+       clc
        rts
 
 ; ------------------------------------------------------------------------