Merge pull request #43 from jamsilva/master

SA1 and SuperFX improvements

1 files changed, 50 insertions, 127 deletions

diff --git a/source/fxemu.c b/source/fxemu.c
index dd798fd..9d62b05 100644
--- a/source/fxemu.c
+++ b/source/fxemu.c
@@ -6,6 +6,8 @@
 #include <string.h>
 #include <stdio.h>
 
+#include <retro_inline.h>
+
 /* The FxChip Emulator's internal variables */
 FxRegs_s GSU; /* This will be initialized when loading a ROM */
 
@@ -27,13 +29,10 @@ void fx_updateRamBank(uint8_t Byte)
    GSU.pvRamBank = GSU.apvRamBank[Byte & 0x3];
 }
 
-static void fx_readRegisterSpaceForCheck(void)
+static INLINE void fx_readRegisterSpaceForCheck(void)
 {
    R15 = GSU.pvRegisters[30];
    R15 |= ((uint32_t) GSU.pvRegisters[31]) << 8;
-   GSU.vStatusReg = (uint32_t) GSU.pvRegisters[GSU_SFR];
-   GSU.vStatusReg |= ((uint32_t) GSU.pvRegisters[GSU_SFR + 1]) << 8;
-   GSU.vPrgBankReg = (uint32_t) GSU.pvRegisters[GSU_PBR];
 }
 
 static void fx_readRegisterSpaceForUse(void)
@@ -52,6 +51,9 @@ static void fx_readRegisterSpaceForUse(void)
 
    /* Update other registers */
    p = GSU.pvRegisters;
+   GSU.vStatusReg = (uint32_t) GSU.pvRegisters[GSU_SFR];
+   GSU.vStatusReg |= ((uint32_t) GSU.pvRegisters[GSU_SFR + 1]) << 8;
+   GSU.vPrgBankReg = (uint32_t) GSU.pvRegisters[GSU_PBR];
    GSU.vRomBankReg = (uint32_t)p[GSU_ROMBR];
    GSU.vRamBankReg = ((uint32_t)p[GSU_RAMBR]) & (FX_RAM_BANKS - 1);
    GSU.vCacheBaseReg = (uint32_t)p[GSU_CBR];
@@ -75,9 +77,9 @@ static void fx_readRegisterSpaceForUse(void)
    GSU.vScreenHeight = GSU.vScreenRealHeight = avHeight[i];
    GSU.vMode = p[GSU_SCMR] & 0x03;
    if (i == 3)
-      GSU.vScreenSize = (256 / 8) * (256 / 8) * 32;
+      GSU.vScreenSize = 32768;
    else
-      GSU.vScreenSize = (GSU.vScreenHeight / 8) * (256 / 8) * avMult[GSU.vMode];
+      GSU.vScreenSize = GSU.vScreenHeight * 4 * avMult[GSU.vMode];
    if (GSU.vPlotOptionReg & 0x10)
       GSU.vScreenHeight = 256; /* OBJ Mode (for drawing into sprites) */
    if (GSU.pvScreenBase + GSU.vScreenSize > GSU.pvRam + (GSU.nRamBanks * 65536))
@@ -90,7 +92,8 @@ static void fx_readRegisterSpaceForUse(void)
    fx_apfOpcodeTable[0x24c] = GSU.pfPlot;
    fx_apfOpcodeTable[0x34c] = GSU.pfRpix;
 
-   fx_computeScreenPointers();
+   if(GSU.vMode != GSU.vPrevMode || GSU.vPrevScreenHeight != GSU.vScreenHeight || GSU.vSCBRDirty)
+      fx_computeScreenPointers();
 }
 
 void fx_dirtySCBR(void)
@@ -100,135 +103,52 @@ void fx_dirtySCBR(void)
 
 void fx_computeScreenPointers(void)
 {
-   if (GSU.vMode != GSU.vPrevMode || GSU.vPrevScreenHeight != GSU.vScreenHeight || GSU.vSCBRDirty)
+   int32_t i, j, condition, mask, result;
+   uint32_t apvIncrement, vMode, xIncrement;
+   GSU.vSCBRDirty = false;
+
+   /* Make a list of pointers to the start of each screen column*/
+   vMode = GSU.vMode;
+   condition = vMode - 2;
+   mask = (condition | -condition) >> 31;
+   result = (vMode & mask) | (3 & ~mask);
+   vMode = result + 1;
+   GSU.x[0] = 0;
+   GSU.apvScreen[0] = GSU.pvScreenBase;
+   apvIncrement = vMode << 4;
+
+   if(GSU.vScreenHeight == 256)
    {
-      int32_t i;
-      GSU.vSCBRDirty = false;
+      GSU.x[16] = vMode << 12;
+      GSU.apvScreen[16] = GSU.pvScreenBase + (vMode << 13);
+      apvIncrement <<= 4;
+      xIncrement = vMode << 4;
 
-      /* Make a list of pointers to the start of each screen column */
-      switch (GSU.vScreenHeight)
+      for(i = 1, j = 17 ; i < 16 ; i++, j++)
+      {
+         GSU.x[i] = GSU.x[i - 1] + xIncrement;
+         GSU.apvScreen[i] = GSU.apvScreen[i - 1] + apvIncrement;
+         GSU.x[j] = GSU.x[j - 1] + xIncrement;
+         GSU.apvScreen[j] = GSU.apvScreen[j - 1] + apvIncrement;
+      }
+   }
+   else
+   {
+      xIncrement = (vMode * GSU.vScreenHeight) << 1;
+      for(i = 1 ; i < 32 ; i++)
       {
-      case 128:
-         switch (GSU.vMode)
-         {
-         case 0:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + (i << 4);
-               GSU.x[i] = i << 8;
-            }
-            break;
-         case 1:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + (i << 5);
-               GSU.x[i] = i << 9;
-            }
-            break;
-         case 2:
-         case 3:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + (i << 6);
-               GSU.x[i] = i << 10;
-            }
-            break;
-         }
-         break;
-      case 160:
-         switch (GSU.vMode)
-         {
-         case 0:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + (i << 4);
-               GSU.x[i] = (i << 8) + (i << 6);
-            }
-            break;
-         case 1:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + (i << 5);
-               GSU.x[i] = (i << 9) + (i << 7);
-            }
-            break;
-         case 2:
-         case 3:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + (i << 6);
-               GSU.x[i] = (i << 10) + (i << 8);
-            }
-            break;
-         }
-         break;
-      case 192:
-         switch (GSU.vMode)
-         {
-         case 0:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + (i << 4);
-               GSU.x[i] = (i << 8) + (i << 7);
-            }
-            break;
-         case 1:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + (i << 5);
-               GSU.x[i] = (i << 9) + (i << 8);
-            }
-            break;
-         case 2:
-         case 3:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + (i << 6);
-               GSU.x[i] = (i << 10) + (i << 9);
-            }
-            break;
-         }
-         break;
-      case 256:
-         switch (GSU.vMode)
-         {
-         case 0:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + ((i & 0x10) << 9) + ((i & 0xf) << 8);
-               GSU.x[i] = ((i & 0x10) << 8) + ((i & 0xf) << 4);
-            }
-            break;
-         case 1:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + ((i & 0x10) << 10) + ((i & 0xf) << 9);
-               GSU.x[i] = ((i & 0x10) << 9) + ((i & 0xf) << 5);
-            }
-            break;
-         case 2:
-         case 3:
-            for (i = 0; i < 32; i++)
-            {
-               GSU.apvScreen[i] = GSU.pvScreenBase + ((i & 0x10) << 11) + ((i & 0xf) << 10);
-               GSU.x[i] = ((i & 0x10) << 10) + ((i & 0xf) << 6);
-            }
-            break;
-         }
-         break;
+         GSU.x[i] = GSU.x[i - 1] + xIncrement;
+         GSU.apvScreen[i] = GSU.apvScreen[i - 1] + apvIncrement;
       }
-      GSU.vPrevMode = GSU.vMode;
-      GSU.vPrevScreenHeight = GSU.vScreenHeight;
    }
+   GSU.vPrevMode = GSU.vMode;
+   GSU.vPrevScreenHeight = GSU.vScreenHeight;
 }
 
-static void fx_writeRegisterSpaceAfterCheck(void)
+static INLINE void fx_writeRegisterSpaceAfterCheck(void)
 {
    GSU.pvRegisters[30] = (uint8_t) R15;
    GSU.pvRegisters[31] = (uint8_t) (R15 >> 8);
-   GSU.pvRegisters[GSU_SFR] = (uint8_t) GSU.vStatusReg;
-   GSU.pvRegisters[GSU_SFR + 1] = (uint8_t) (GSU.vStatusReg >> 8);
-   GSU.pvRegisters[GSU_PBR] = (uint8_t) GSU.vPrgBankReg;
 }
 
 static void fx_writeRegisterSpaceAfterUse(void)
@@ -260,6 +180,9 @@ static void fx_writeRegisterSpaceAfterUse(void)
       CF(CY);
 
    p = GSU.pvRegisters;
+   p[GSU_SFR] = (uint8_t) GSU.vStatusReg;
+   p[GSU_SFR + 1] = (uint8_t) (GSU.vStatusReg >> 8);
+   p[GSU_PBR] = (uint8_t) GSU.vPrgBankReg;
    p[GSU_ROMBR] = (uint8_t)GSU.vRomBankReg;
    p[GSU_RAMBR] = (uint8_t)GSU.vRamBankReg;
    p[GSU_CBR] = (uint8_t)GSU.vCacheBaseReg;
@@ -342,7 +265,7 @@ static bool fx_checkStartAddress(void)
       return false;
 
    /* Check if we're in RAM and the RAN flag is not set */
-   if (GSU.vPrgBankReg >= 0x70 && GSU.vPrgBankReg <= 0x73 && !(SCMR & (1 << 3)))
+   if (GSU.vPrgBankReg >= 0x70 && !(SCMR & (1 << 3)))
       return false;
 
    /* If not, we're in ROM, so check if the RON flag is set */