6502/cc65
1
0
Fork 0
mirror of https://github.com/cc65/cc65.git synced 2025-01-11 11:30:13 +00:00
Code Issues Projects Releases Wiki Activity

xlmemchk.inc: Fix wrong calculation if load address is at an exact 4K border.

Browse Source
This commit is contained in:
Christian Groessler 2013-08-27 22:45:23 +02:00
parent e12fbe35a8
commit ae9ab59549
1 changed files with 9 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
libsrc/atari/xlmemchk.inc
View File

@ -61,13 +61,17 @@ scrmemtst:
cmp tmp
beq scrmemok
; if lodadr is at an exact 4K boundary, it's still ok
lda lodadr+1
and #$0f
beq scrmemok
; 4K boundary will be crossed, use this 4K boundary address as lodadr
al4k: lda lodadr+1
and #$f0
tax
dex
stx lodadr+1
sta lodadr+1
bne scrmemtst
; not reached
@ -89,6 +93,7 @@ scrmemok:
sbc #>DLSZ
sta lowadr+1
.if 0 ; this cannot happen
; check if a 1K boundary is crossed
lda tstadr+1
@ -98,6 +103,7 @@ scrmemok:
and #$fc
cmp tmp
bne al4k ; 1K boundary will be crossed, decrease lodadr
.endif
; address of display list is ok
; decrease lowadr by two