RGA queued data must be fully processed before accepting CPU accesses.

diff --git a/drawing.cpp b/drawing.cpp
index d552d760caddb91380dfe8c4c96bdf58a5f34ee8..dbcd324c1b1f2ed6a44d606e5d7da765201729a6 100644 (file)
--- a/drawing.cpp
+++ b/drawing.cpp
@@ -387,7 +387,7 @@ static bool aga_genlock_features_zdclken;
 
 uae_sem_t gui_sem;
 
-static int rga_denise_fast_read, rga_denise_fast_write;
+static volatile int rga_denise_fast_read, rga_denise_fast_write;
 #define DENISE_RGA_SLOT_FAST_TOTAL 1024
 static struct denise_rga rga_denise_fast[DENISE_RGA_SLOT_FAST_TOTAL];
 
@@ -3904,15 +3904,18 @@ static void flush_fast_rga(uae_u32 linecnt)
 {
        // extract fast CPU RGA pipeline
        while (rga_denise_fast_write != rga_denise_fast_read) {
-               struct denise_rga *rd = &rga_denise_fast[rga_denise_fast_read];
-               if (linecnt < rd->line) {
+               int rp = rga_denise_fast_read;
+               struct denise_rga *rd = &rga_denise_fast[rp];
+               // Any RGA queued accesses must be processed first
+               if (linecnt <= rd->line) {
                        break;
                }
                expand_drga(rd);
                expand_drga_early(rd);
                expand_drga_early2x(rd);
-               rga_denise_fast_read++;
-               rga_denise_fast_read &= DENISE_RGA_SLOT_FAST_TOTAL - 1;
+               rp++;
+               rp &= DENISE_RGA_SLOT_FAST_TOTAL - 1;
+               rga_denise_fast_read = rp;
        }
 }
 
@@ -4662,15 +4665,17 @@ static void denise_handle_quick_strobe(uae_u16 strobe, int offset, int vpos)
 
 bool denise_update_reg_queued(uae_u16 reg, uae_u16 v, uae_u32 linecnt)
 {
-       if (((rga_denise_fast_write + 1) & (DENISE_RGA_SLOT_FAST_TOTAL - 1))  == rga_denise_fast_read) {
+       int wp = rga_denise_fast_write;
+       if (((wp + 1) & (DENISE_RGA_SLOT_FAST_TOTAL - 1)) == rga_denise_fast_read) {
                return false;
        }
-       struct denise_rga *r = &rga_denise_fast[rga_denise_fast_write];
+       struct denise_rga *r = &rga_denise_fast[wp];
        r->rga = reg;
        r->v = v;
        r->line = linecnt;
-       rga_denise_fast_write++;
-       rga_denise_fast_write &= DENISE_RGA_SLOT_FAST_TOTAL - 1;
+       wp++;
+       wp &= DENISE_RGA_SLOT_FAST_TOTAL - 1;
+       rga_denise_fast_write = wp;
        return true;
 }