interrupt flag is cleared/restored rather than cleared/set

[cc65] / libsrc / plus4 / break.s

diff --git a/libsrc/plus4/break.s b/libsrc/plus4/break.s
index 4365534261c72d08a650fcf2c95fed28bb4e19d7..d6f1449770108ef0451662ea70265d6b3b7a1b39 100644 (file)
--- a/libsrc/plus4/break.s
+++ b/libsrc/plus4/break.s
@@ -6,8 +6,8 @@
 ;
 
                .export         _set_brk, _reset_brk
+       .destructor     _reset_brk
        .export         _brk_a, _brk_x, _brk_y, _brk_sr, _brk_pc
-       .import         _atexit
 
        .include        "plus4.inc"
 
@@ -43,10 +43,6 @@ uservec:     jmp     $FFFF           ; Patched at runtime
        lda     BRKVec+1
        sta     oldvec+1        ; Save the old vector
 
-       lda     #<_reset_brk
-       ldx     #>_reset_brk
-       jsr     _atexit         ; Install an exit handler
-
 L1:    lda     #<brk_handler   ; Set the break vector to our routine
        sta     BRKVec
        lda     #>brk_handler
@@ -59,11 +55,13 @@ L1: lda     #<brk_handler   ; Set the break vector to our routine
 ; Reset the break vector
 .proc  _reset_brk
 
-       lda     oldvec
-       sta     BRKVec
-       lda     oldvec+1
-       sta     BRKVec+1
-       rts
+       lda     oldvec
+       bne     @L1
+       ldx     oldvec
+       beq     @L9             ; Jump if vector not installed
+@L1:   sta     BRKVec
+       stx     BRKVec+1
+@L9:   rts
 
 .endproc