Reading non-existing register fix

diff --git a/custom.cpp b/custom.cpp
index 8b72c8c1d466aa2fab8448bd1b3ecb805223fd78..e0ad5d65e624c6df2399feda1d0426c01afddd7f 100644 (file)
--- a/custom.cpp
+++ b/custom.cpp
@@ -13727,8 +13727,9 @@ writeonly:
                        // - if last cycle was DMA cycle: DMA cycle data
                        // - if last cycle was not DMA cycle: FFFF or some ANDed old data.
                        //
-                       c = cycle_line_slot[hpos] & CYCLE_MASK;
-                       bmdma = bitplane_dma_access(hpos, 0);
+                       int hp = (hpos - 1) % maxhpos;
+                       c = cycle_line_slot[hp] & CYCLE_MASK;
+                       bmdma = bitplane_dma_access(hp, 0);
                        if (aga_mode) {
                                if (bmdma || (c > CYCLE_REFRESH && c < CYCLE_CPU)) {
                                        v = regs.chipset_latch_rw;