Use php/sei/plp to preserve original state of the interrupt flag

2025-11-28 11:09:21 -08:00
parent c14f2b7252
commit 5296d394e4
2 changed files with 4 additions and 2 deletions
--- a/libsrc/c65/cpeekcolor.s
+++ b/libsrc/c65/cpeekcolor.s
@@ -18,6 +18,7 @@ _cpeekcolor:
        lda     SCREEN_PTR
        sta     ptr1

+        php
        sei
        lda     $D030
        ora     #$01
@@ -28,8 +29,8 @@ _cpeekcolor:
        lda     $D030
        and     #$FE
        sta     $D030
-        cli
        tya
+        plp

        ldx     #>$0000
        rts
--- a/libsrc/c65/cputc.s
+++ b/libsrc/c65/cputc.s
@@ -116,6 +116,7 @@ putchar:
        adc     #>$D000
        sta     ptr4 + 1

+        php
        sei
        lda     $D030
        ora     #$01
@@ -125,6 +126,6 @@ putchar:
        lda     $D030
        and     #$FE
        sta     $D030
-        cli
+        plp

        rts