rework sr

note to self:

h32 0x10A .. 0x127 0x1D2 .. 0x1FF 0x000 .. 0x109
pclk      30      |      46      |      266      = 342
hbset       0x126        ...       0x009
pclk   29  |      1   +  46    +  10    |  256
mclk   290 |           570              |  2560  = 3420
68kclk 41.4            81.4               365.7 ~= 488.5

h40 0x14A .. 0x16C 0x1C9 .. 0x1FF 0x000 .. 0x149
pclk      35      |      55      |      330      = 420
hbset       0x166        ...       0x00A
pclk   28  |      7   +  55    +  11    |  319
mclk  28*8 | 7*8   4*8+314+10+(18+11)*8 | 319*8  = 3420
68kclk  32             92                 364.5 ~= 488.5

pico/pico_cmn.c

@@ -108,7 +108,7 @@ static int PicoFrameHints(void)
   }
   else skip=PicoSkipFrame;
 
-  Pico.t.m68c_frame_start = SekCyclesDone();
+  Pico.t.m68c_frame_start = Pico.t.m68c_aim;
   pv->v_counter = Pico.m.scanline = 0;
   z80_resetCycles();
   PsndStartFrame();
@@ -170,7 +170,7 @@ static int PicoFrameHints(void)
     }
 
     // Run scanline:
-    Pico.t.m68c_line_start = SekCyclesDone();
+    Pico.t.m68c_line_start = Pico.t.m68c_aim;
     do_timing_hacks_as(pv, vdp_slots);
     CPUS_RUN(CYCLES_M68K_LINE);
 
@@ -205,16 +205,17 @@ static int PicoFrameHints(void)
     do_hint(pv);
   }
 
-  pv->status |= SR_VB; // go into vblank
+  pv->status |= SR_VB | PVS_VB2; // go into vblank
 
   // the following SekRun is there for several reasons:
   // there must be a delay after vblank bit is set and irq is asserted (Mazin Saga)
   // also delay between F bit (bit 7) is set in SR and IRQ happens (Ex-Mutants)
   // also delay between last H-int and V-int (Golden Axe 3)
-  Pico.t.m68c_line_start = SekCyclesDone();
+  Pico.t.m68c_line_start = Pico.t.m68c_aim;
   do_timing_hacks_vb();
   CPUS_RUN(CYCLES_M68K_VINT_LAG);
 
+  pv->status |= SR_F;
   pv->pending_ints |= 0x20;
   if (pv->reg[1] & 0x20) {
     Pico.t.m68c_aim = Pico.t.m68c_cnt + 11; // HACK
@@ -278,7 +279,7 @@ static int PicoFrameHints(void)
     }
 
     // Run scanline:
-    Pico.t.m68c_line_start = SekCyclesDone();
+    Pico.t.m68c_line_start = Pico.t.m68c_aim;
     do_timing_hacks_vb();
     CPUS_RUN(CYCLES_M68K_LINE);
 
@@ -286,7 +287,8 @@ static int PicoFrameHints(void)
     pevt_log_m68k_o(EVT_NEXT_LINE);
   }
 
-  pv->status &= ~SR_VB;
+  pv->status &= ~(SR_VB | PVS_VB2);
+  pv->status |= ((pv->reg[1] >> 3) ^ SR_VB) & SR_VB; // forced blanking
 
   // last scanline
   Pico.m.scanline = y;
@@ -302,7 +304,7 @@ static int PicoFrameHints(void)
   }
 
   // Run scanline:
-  Pico.t.m68c_line_start = SekCyclesDone();
+  Pico.t.m68c_line_start = Pico.t.m68c_aim;
   do_timing_hacks_as(pv, vdp_slots);
   CPUS_RUN(CYCLES_M68K_LINE);
 

pico/pico_int.h

@@ -287,6 +287,7 @@ extern SH2 sh2s[2];
 #define SR_EMPT       (1 << 9)
 // not part of real SR
 #define PVS_ACTIVE    (1 << 16)
+#define PVS_VB2       (1 << 17) // ignores forced blanking
 
 struct PicoVideo
 {

pico/sek.c

@@ -34,6 +34,7 @@ static int do_ack(int level)
   // the VDP doesn't look at the 68k level
   if (pv->pending_ints & pv->reg[1] & 0x20) {
     pv->pending_ints &= ~0x20;
+    pv->status &= ~SR_F;
     return (pv->reg[0] & pv->pending_ints & 0x10) >> 2;
   }
   else if (pv->pending_ints & pv->reg[0] & 0x10)

pico/state.c

@@ -564,6 +564,8 @@ readend:
 
   Pico.m.dirtyPal = 1;
   Pico.video.status &= ~(SR_VB | SR_F);
+  Pico.video.status |= ((Pico.video.reg[1] >> 3) ^ SR_VB) & SR_VB;
+  Pico.video.status |= (Pico.video.pending_ints << 2) & SR_F;
 
   retval = 0;
 

pico/videoport.c

@@ -376,8 +376,7 @@ PICO_INTERNAL_ASM void PicoVideoWrite(unsigned int a,unsigned short d)
       pvid->pending=0;
     }
 
-    // preliminary FIFO emulation for Chaos Engine, The (E)
+    if (!(pvid->status & SR_VB) && !(PicoOpt&POPT_DIS_VDP_FIFO))
-    if (!(pvid->status & SR_VB) && (pvid->reg[1] & 0x40) && !(PicoOpt&POPT_DIS_VDP_FIFO)) // active display?
     {
       int use = pvid->type == 1 ? 2 : 1;
       pvid->lwrite_cnt -= use;
@@ -434,6 +433,9 @@ PICO_INTERNAL_ASM void PicoVideoWrite(unsigned int a,unsigned short d)
           case 0x01:
             elprintf(EL_INTSW, "vint_onoff: %i->%i [%u] pend=%i @ %06x", (dold&0x20)>>5,
                     (d&0x20)>>5, SekCyclesDone(), (pvid->pending_ints&0x20)>>5, SekPc);
+            if (!(pvid->status & PVS_VB2))
+              pvid->status &= ~SR_VB;
+            pvid->status |= ((d >> 3) ^ SR_VB) & SR_VB; // forced blanking
             goto update_irq;
           case 0x05:
             //elprintf(EL_STATUS, "spritep moved to %04x", (unsigned)(Pico.video.reg[5]&0x7f) << 9);
@@ -503,6 +505,16 @@ update_irq:
   }
 }
 
+static u32 SrLow(const struct PicoVideo *pv)
+{
+  unsigned int c, d = pv->status;
+
+  c = SekCyclesDone() - Pico.t.m68c_line_start - 39;
+  if (c < 92)
+    d |= SR_HB;
+  return d;
+}
+
 PICO_INTERNAL_ASM unsigned int PicoVideoRead(unsigned int a)
 {
   a &= 0x1c;
@@ -510,18 +522,8 @@ PICO_INTERNAL_ASM unsigned int PicoVideoRead(unsigned int a)
   if (a == 0x04) // control port
   {
     struct PicoVideo *pv = &Pico.video;
-    unsigned int d;
+    unsigned int d = SrLow(pv);
-    d=pv->status;
+    pv->pending = 0;
-    //if (PicoOpt&POPT_ALT_RENDERER) d|=0x0020; // sprite collision (Shadow of the Beast)
-    if (SekCyclesDone() - Pico.t.m68c_line_start >= 488-88)
-      d|=0x0004; // H-Blank (Sonic3 vs)
-
-    d |= ((pv->reg[1]&0x40)^0x40) >> 3;  // set V-Blank if display is disabled
-    d |= (pv->pending_ints&0x20)<<2;     // V-int pending?
-    if (d&0x100) pv->status&=~0x100; // FIFO no longer full
-
-    pv->pending = 0; // ctrl port reads clear write-pending flag (Charles MacDonald)
-
     elprintf(EL_SR, "SR read: %04x [%u] @ %06x", d, SekCyclesDone(), SekPc);
     return d;
   }
@@ -572,12 +574,9 @@ unsigned char PicoVideoRead8DataL(void)
   return VideoRead();
 }
 
-// FIXME: broken mess
 unsigned char PicoVideoRead8CtlH(void)
 {
   u8 d = (u8)(Pico.video.status >> 8);
-  if (d & 1)
-    Pico.video.status &= ~0x100; // FIFO no longer full
   Pico.video.pending = 0;
   elprintf(EL_SR, "SR read (h): %02x @ %06x", d, SekPc);
   return d;
@@ -585,11 +584,7 @@ unsigned char PicoVideoRead8CtlH(void)
 
 unsigned char PicoVideoRead8CtlL(void)
 {
-  u8 d = (u8)Pico.video.status;
+  u8 d = SrLow(&Pico.video);
-  //if (PicoOpt&POPT_ALT_RENDERER) d|=0x0020; // sprite collision (Shadow of the Beast)
-  d |= ((Pico.video.reg[1]&0x40)^0x40) >> 3;  // set V-Blank if display is disabled
-  d |= (Pico.video.pending_ints&0x20)<<2;     // V-int pending?
-  if (SekCyclesDone() - Pico.t.m68c_line_start >= 488-88) d |= 4;    // H-Blank
   Pico.video.pending = 0;
   elprintf(EL_SR, "SR read (l): %02x @ %06x", d, SekPc);
   return d;