Fixed bug in VDU5 bit shifting

2023-01-12 19:16:40 -05:00 · 2023-01-12 19:16:40 -05:00 · 24a251ffa2
parent ffb61077bf
commit 24a251ffa2
2 changed files with 4 additions and 0 deletions
--- a/applecorn.po
+++ b/applecorn.po
--- a/mainmem.shr.s
+++ b/mainmem.shr.s
@ -292,6 +292,8 @@ SHRVDU5CH     >>>   ENTMAIN
 :L0           
              PHX
              LDY   #$00
+              STZ   :PIXBUF+2              ; Clear bytes 3,4 of shift buf
+              STZ   :PIXBUF+4              ; Clear bytes 5,6 of shift buf
 :LOOP         LDAL  $E10000,X              ; Read a word of exploded font
              STA   :PIXBUF,Y              ; Store word to shift buffer
              INX
@ -305,6 +307,7 @@ SHRVDU5CH     >>>   ENTMAIN
              LDY   A2L                    ; Index into row of pixels
              STZ   :COLCTR
              LDX   #$00
+              INC   :BYTES
 :L1           LDA   :PIXBUF,X              ; Read word of exploded font
              PHX
              SEP   #$30                   ; 8 bit M & X
@ -319,6 +322,7 @@ SHRVDU5CH     >>>   ENTMAIN
              LDA   :COLCTR
              CMP   :BYTES                 ; Bytes per row 
              BNE   :L1
+              DEC   :BYTES

              PLA                          ; Restore saved X -> A
              CLC                          ; Add bytes per row