Emulate undocumented FMODE>0 bitplane modulo feature if modulo/bpltpt is unaligned.

diff --git a/custom.cpp b/custom.cpp
index 5ae7ccaffebc8b4c682cc5a444378f3f02124225..b5a87a84d8d0c654f4f26552587084a477bed71d 100644 (file)
--- a/custom.cpp
+++ b/custom.cpp
@@ -683,7 +683,7 @@ STATIC_INLINE int get_equ_vblank_endline (void)
 /* Called to determine the state of the horizontal display window state
 * machine at the current position. It might have changed since we last
 * checked.  */
-static void decide_diw (int hpos)
+static void decide_diw(int hpos)
 {
        /* Last hpos = hpos + 0.5, eg. normal PAL end hpos is 227.5 * 2 = 455
           OCS Denise: 9 bit hdiw counter does not reset during lines 0 to 9
@@ -692,7 +692,7 @@ static void decide_diw (int hpos)
        */
 
        int hdiw = hpos >= maxhpos ? maxhpos * 2 + 1 : hpos * 2 + 2;
-       if (!(currprefs.chipset_mask & CSMASK_ECS_DENISE) && vpos <= get_equ_vblank_endline ())
+       if (!(currprefs.chipset_mask & CSMASK_ECS_DENISE) && vpos <= get_equ_vblank_endline())
                hdiw = diw_hcounter;
        /* always mask, bad programs may have set maxhpos = 256 */
        hdiw &= 511;
@@ -718,16 +718,17 @@ static void decide_diw (int hpos)
        last_hdiw = hdiw;
 }
 
-static int fetchmode, fetchmode_size, fetchmode_mask, fetchmode_bytes, fetchmode_fmode;
+static int fetchmode, fetchmode_size, fetchmode_mask, fetchmode_bytes;
+static int fetchmode_fmode_bpl, fetchmode_fmode_spr;
 static int fetchmode_size_hr, fetchmode_mask_hr;
 static int real_bitplane_number[3][3][9];
 
 /* Disable bitplane DMA if planes > available DMA slots. This is needed
 e.g. by the Sanity WOC demo (at the "Party Effect").  */
-STATIC_INLINE int GET_PLANES_LIMIT (uae_u16 bc0)
+STATIC_INLINE int GET_PLANES_LIMIT(uae_u16 bc0)
 {
-       int res = GET_RES_AGNUS (bc0);
-       int planes = GET_PLANES (bc0);
+       int res = GET_RES_AGNUS(bc0);
+       int planes = GET_PLANES(bc0);
        return real_bitplane_number[fetchmode][res][planes];
 }
 
@@ -741,7 +742,7 @@ static void reset_dbplh(int hpos, int num)
        }
 }
 
-static void reset_dbplh_all (int hpos)
+static void reset_dbplh_all(int hpos)
 {
        if (dbplpth_on2) {
                for (int num = 0; num < MAX_PLANES; num++) {
@@ -751,7 +752,7 @@ static void reset_dbplh_all (int hpos)
        }
 }
 
-static void reset_dbpll (int hpos, int num)
+static void reset_dbpll(int hpos, int num)
 {
        if (dbplptl_on[num] && hpos >= dbplptl_on[num]) {
                bplpt[num] = (bplpt[num] & 0xffff0000) | dbplptl[num];
@@ -760,7 +761,7 @@ static void reset_dbpll (int hpos, int num)
        }
 }
 
-static void reset_dbpll_all (int hpos)
+static void reset_dbpll_all(int hpos)
 {
        if (dbplptl_on2) {
                for (int num = 0; num < MAX_PLANES; num++) {
@@ -771,7 +772,7 @@ static void reset_dbpll_all (int hpos)
 }
 #endif
 
-static void reset_moddelays (void)
+static void reset_moddelays(void)
 {
        if (dbpl1mod_on > 0) {
                bpl1mod = dbpl1mod;
@@ -783,6 +784,26 @@ static void reset_moddelays (void)
        }
 }
 
+static void add_mod(int nr, int mod)
+{
+#ifdef AGA
+       if (fetchmode_fmode_bpl == 1 || fetchmode_fmode_bpl == 2) {
+               // FMODE=1/2, unaligned bpl and modulo: bit 1 carry is ignored.
+               if ((bplpt[nr] & 2) && (mod & 2)) {
+                       mod -= 4;
+               }
+       } else if (fetchmode_fmode_bpl == 3) {
+               // FMODE=3, unaligned bpl and modulo: bit 2 carry is ignored.
+               if ((bplpt[nr] & (4 | 2)) + (mod & (4 | 2)) >= 8) {
+                       mod -= 8;
+               }
+       }
+#endif
+
+       bplpt[nr] += mod;
+       bplptx[nr] += mod;
+}
+
 static void add_modulo (int hpos, int nr)
 {
        int mod;
@@ -804,8 +825,7 @@ static void add_modulo (int hpos, int nr)
                mod = bpl2mod;
        else
                mod = bpl1mod;
-       bplpt[nr] += mod;
-       bplptx[nr] += mod;
+       add_mod(nr, mod);
        reset_moddelays ();
 #if 0
        reset_dbpll_all (-1);
@@ -832,15 +852,15 @@ static void add_modulos (void)
 
        switch (bplcon0_planes_limit) {
 #ifdef AGA
-       case 8: bplpt[7] += m2; bplptx[7] += m2;
-       case 7: bplpt[6] += m1; bplptx[6] += m1;
+       case 8: add_mod(7, m2);
+       case 7: add_mod(6, m1);
 #endif
-       case 6: bplpt[5] += m2; bplptx[5] += m2;
-       case 5: bplpt[4] += m1; bplptx[4] += m1;
-       case 4: bplpt[3] += m2; bplptx[3] += m2;
-       case 3: bplpt[2] += m1; bplptx[2] += m1;
-       case 2: bplpt[1] += m2; bplptx[1] += m2;
-       case 1: bplpt[0] += m1; bplptx[0] += m1;
+       case 6: add_mod(5, m2);
+       case 5: add_mod(4, m1);
+       case 4: add_mod(3, m2);
+       case 3: add_mod(2, m1);
+       case 2: add_mod(1, m2);
+       case 1: add_mod(0, m1);
        }
 }
 
@@ -1242,7 +1262,8 @@ static void setup_fmodes (int hpos)
        fetchmode_size = 16 << fetchmode;
        fetchmode_bytes = 2 << fetchmode;
        fetchmode_mask = fetchmode_size - 1;
-       fetchmode_fmode = fmode;
+       fetchmode_fmode_bpl = fmode & 3;
+       fetchmode_fmode_spr = (fmode >> 2) & 3;
        compute_toscr_delay (bplcon1);
 
        if (thisline_decision.plfleft < 0) {
@@ -1426,27 +1447,27 @@ static void fetch (int nr, int fm, bool modulo, int hpos)
                switch (fm)
                {
                case 0:
-                       {
-                               uae_u16 v;
-                               if (aga_mode) {
-                                       // AGA always does 32-bit fetches, this is needed
-                                       // to emulate 64 pixel wide sprite side-effects.
-                                       uae_u32 vv = chipmem_lget_indirect(p & ~3);
-                                       if (p & 2) {
-                                               v = (uae_u16)vv;
-                                               fetched_aga_spr[nr] = (v << 16) | v;
-                                       } else {
-                                               v = vv >> 16;
-                                               fetched_aga_spr[nr] = vv;
-                                       }
+               {
+                       uae_u16 v;
+                       if (aga_mode) {
+                               // AGA always does 32-bit fetches, this is needed
+                               // to emulate 64 pixel wide sprite side-effects.
+                               uae_u32 vv = chipmem_lget_indirect(p & ~3);
+                               if (p & 2) {
+                                       v = (uae_u16)vv;
+                                       fetched_aga_spr[nr] = (v << 16) | v;
                                } else {
-                                       v = chipmem_wget_indirect(p);
+                                       v = vv >> 16;
+                                       fetched_aga_spr[nr] = vv;
                                }
-                               fetched_aga[nr] = fetched[nr] = v;
-                               last_custom_value1 = v;
-                               last_custom_value2 = (uae_u16)last_custom_value1;
+                       } else {
+                               v = chipmem_wget_indirect(p);
                        }
+                       fetched_aga[nr] = fetched[nr] = v;
+                       last_custom_value1 = v;
+                       last_custom_value2 = (uae_u16)last_custom_value1;
                        break;
+               }
 #ifdef AGA
                case 1:
                {
@@ -1454,7 +1475,7 @@ static void fetch (int nr, int fm, bool modulo, int hpos)
                        if (p & 2) {
                                fetched_aga[nr] = chipmem_lget_indirect(pm) & 0x0000ffff;
                                fetched_aga[nr] |= fetched_aga[nr] << 16;
-                       } else if (fetchmode_fmode & 2) { // optimized (fetchmode_fmode & 3) == 2
+                       } else if (fetchmode_fmode_bpl & 2) { // optimized (fetchmode_fmode & 3) == 2
                                fetched_aga[nr] = chipmem_lget_indirect(pm) & 0xffff0000;
                                fetched_aga[nr] |= fetched_aga[nr] >> 16;
                        } else {
@@ -2459,7 +2480,7 @@ STATIC_INLINE void long_fetch_32 (int plane, int nwords, int weird_number_of_bit
                        if (unaligned) {
                                fetchval &= 0x0000ffff;
                                fetchval |= fetchval << 16;
-                       } else if (fetchmode_fmode & 2) {
+                       } else if (fetchmode_fmode_bpl & 2) {
                                fetchval &= 0xffff0000;
                                fetchval |= fetchval >> 16;
                        }
@@ -7565,7 +7586,7 @@ static void sprite_fetch_full(struct sprite *s, int hpos, int cycle, int mode, u
                if (s->pt & 2) {
                        data321 &= 0x0000ffff;
                        data321 |= data321 << 16;
-               } else if (fetchmode_fmode & 8) {
+               } else if (fetchmode_fmode_spr & 2) {
                        data321 &= 0xffff0000;
                        data321 |= data321 >> 16;
                }