FIX: xVdcBufswap needed to start with bitmap 0.

Author: Brian Holdsworth

cbm/toolx/vdc/core.asm

@@ -1028,25 +1028,25 @@ xVdcDblBuffer = *
    rts
 
 xVdcBufswap = *
-   ; bmadr1 <- R12/13
+   ; bmadr0 <- R12/13
    ldx #12
    jsr vdcRead
-   sta .bmadr1+1
+   sta .bmadr0+1
    ldx #13
    jsr vdcRead
-   sta .bmadr1+0
-   ; R12/13 <- bmadr0
+   sta .bmadr0+0
+   ; R12/13 <- bmadr1
    ldx #12
-   lda .bmadr0+1
+   lda .bmadr1+1
    jsr vdcWrite
    ldx #13
-   lda .bmadr0+0
-   jsr vdcWrite
-   ; bmadr0 <- bmadr1
    lda .bmadr1+0
-   ldy .bmadr1+1
-   sta .bmadr0+0
-   sty .bmadr0+1
+   jsr vdcWrite
+   ; bmadr1 <- bmadr0
+   lda .bmadr0+0
+   ldy .bmadr0+1
+   sta .bmadr1+0
+   sty .bmadr1+1
    rts
 }