dont trash akku if possible, use VDC register when in 80column mode

2024-06-08 15:29:37 +00:00 · 2017-06-21 23:18:00 +02:00 · 2017-06-21 23:18:00 +02:00 · 49aad01bf1
commit 49aad01bf1
parent 035621aa95
2 changed files with 16 additions and 4 deletions
--- a/libsrc/c128/waitvblank.s
+++ b/libsrc/c128/waitvblank.s
@ -4,10 +4,22 @@
        .include        "c128.inc"

 _waitvblank:
+
+        lda     MODE
+        bmi     @c80
+
@l1:
-        lda     VIC_CTRL1
+        bit     VIC_CTRL1
        bpl     @l1
@l2:
-        lda     VIC_CTRL1
+        bit     VIC_CTRL1
        bmi     @l2
        rts
+
+@c80:
+        ;FIXME: do we have to switch banks?
+@l3:
+        lda     VDC_INDEX
+        and     #$20
+        beq     @l3
+        rts
--- a/libsrc/c64/waitvblank.s
+++ b/libsrc/c64/waitvblank.s
@ -5,9 +5,9 @@

 _waitvblank:
@l1:
-        lda     VIC_CTRL1
+        bit     VIC_CTRL1
        bpl     @l1
@l2:
-        lda     VIC_CTRL1
+        bit     VIC_CTRL1
        bmi     @l2
        rts