1 files changed, 132 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/cRSID/C64/MEM.c b/lib/rbcodec/codecs/cRSID/C64/MEM.c
new file mode 100644
index 0000000000..5be0fc47db
--- /dev/null
+++ b/lib/rbcodec/codecs/cRSID/C64/MEM.c
@@ -0,0 +1,132 @@
+
+//Emulation of C64 memories and memory bus (PLA & MUXes)
+
+
+static inline unsigned char* cRSID_getMemReadPtr (register unsigned short address) {
+ //cRSID_C64instance* const C64 = &cRSID_C64; //for faster (?) operation we use a global object as memory
+ if (address<0xA000) return &cRSID_C64.RAMbank[address];
+ else if ( 0xD000<=address && address<0xE000 && (cRSID_C64.RAMbank[1]&3) ) {
+  if (0xD400 <= address && address < 0xD419) return &cRSID_C64.IObankWR[address]; //emulate bitfading aka SID-read of last written reg (e.g. Lift Off ROR $D400,x)
+  return &cRSID_C64.IObankRD[address];
+ }
+ else if ( (address<0xC000 && (cRSID_C64.RAMbank[1]&3)==3)
+           || (0xE000<=address && (cRSID_C64.RAMbank[1]&2)) ) return &cRSID_C64.ROMbanks[address];
+ return &cRSID_C64.RAMbank[address];
+}
+
+static inline unsigned char* cRSID_getMemReadPtrC64 (cRSID_C64instance* C64, register unsigned short address) {
+ if (address<0xA000) return &C64->RAMbank[address];
+ else if ( 0xD000<=address && address<0xE000 && (C64->RAMbank[1]&3) ) {
+  if (0xD400 <= address && address < 0xD419) return &cRSID_C64.IObankWR[address]; //emulate peculiar SID-read (e.g. Lift Off)
+  return &C64->IObankRD[address];
+ }
+ else if ( (address<0xC000 && (C64->RAMbank[1]&3)==3)
+           || (0xE000<=address && (C64->RAMbank[1]&2)) ) return &C64->ROMbanks[address];
+ return &C64->RAMbank[address];
+}
+
+
+static inline unsigned char* cRSID_getMemWritePtr (register unsigned short address) {
+ //cRSID_C64instance* const C64 = &cRSID_C64; //for faster (?) operation we use a global object as memory
+ if (address<0xD000 || 0xE000<=address) return &cRSID_C64.RAMbank[address];
+ else if ( cRSID_C64.RAMbank[1]&3 ) { //handle SID-mirrors! (CJ in the USA workaround (writing above $d420, except SID2/SID3))
+  if (0xD420 <= address && address < 0xD800) { //CIA/VIC mirrors needed?
+   if ( !(cRSID_C64.PSIDdigiMode && 0xD418 <= address && address < 0xD500)
+        && !(cRSID_C64.SID[2].BaseAddress <= address && address < cRSID_C64.SID[2].BaseAddress+0x20)
+        && !(cRSID_C64.SID[3].BaseAddress <= address && address < cRSID_C64.SID[3].BaseAddress+0x20) ) {
+    return &cRSID_C64.IObankWR[ 0xD400 + (address&0x1F) ]; //write to $D400..D41F if not in SID2/SID3 address-space
+   }
+   else return &cRSID_C64.IObankWR[address];
+  }
+  else return &cRSID_C64.IObankWR[address];
+ }
+ return &cRSID_C64.RAMbank[address];
+}
+
+
+static inline unsigned char* cRSID_getMemWritePtrC64 (cRSID_C64instance* C64, register unsigned short address) {
+ if (address<0xD000 || 0xE000<=address) return &C64->RAMbank[address];
+ else if ( C64->RAMbank[1]&3 ) { //handle SID-mirrors! (CJ in the USA workaround (writing above $d420, except SID2/SID3/PSIDdigi))
+  if (0xD420 <= address && address < 0xD800) { //CIA/VIC mirrors needed?
+   if ( !(cRSID_C64.PSIDdigiMode && 0xD418 <= address && address < 0xD500)
+        && !(C64->SID[2].BaseAddress <= address && address < C64->SID[2].BaseAddress+0x20)
+        && !(C64->SID[3].BaseAddress <= address && address < C64->SID[3].BaseAddress+0x20) ) {
+    return &C64->IObankWR[ 0xD400 + (address&0x1F) ]; //write to $D400..D41F if not in SID2/SID3 address-space
+   }
+   else return &C64->IObankWR[address];
+  }
+  else return &C64->IObankWR[address];
+ }
+ return &C64->RAMbank[address];
+}
+
+
+static inline unsigned char cRSID_readMem (register unsigned short address) {
+ return *cRSID_getMemReadPtr(address);
+}
+
+static inline unsigned char cRSID_readMemC64 (cRSID_C64instance* C64, register unsigned short address) {
+ return *cRSID_getMemReadPtrC64(C64,address);
+}
+
+
+static inline void cRSID_writeMem (register unsigned short address, register unsigned char data) {
+ *cRSID_getMemWritePtr(address)=data;
+}
+
+static inline void cRSID_writeMemC64 (cRSID_C64instance* C64, register unsigned short address, register unsigned char data) {
+ *cRSID_getMemWritePtrC64(C64,address)=data;
+}
+
+
+void cRSID_setROMcontent (cRSID_C64instance* C64) { //fill KERNAL/BASIC-ROM areas with content needed for SID-playback
+ int i;
+ static const unsigned char ROM_IRQreturnCode[9] = {0xAD,0x0D,0xDC,0x68,0xA8,0x68,0xAA,0x68,0x40}; //CIA1-acknowledge IRQ-return
+ static const unsigned char ROM_NMIstartCode[5] = {0x78,0x6c,0x18,0x03,0x40}; //SEI and jmp($0318)
+ static const unsigned char ROM_IRQBRKstartCode[19] = { //Full IRQ-return (handling BRK with the same RAM vector as IRQ)
+  0x48,0x8A,0x48,0x98,0x48,0xBA,0xBD,0x04,0x01,0x29,0x10,0xEA,0xEA,0xEA,0xEA,0xEA,0x6C,0x14,0x03
+ };
+
+ for (i=0xA000; i<0x10000; ++i) C64->ROMbanks[i] = 0x60; //RTS (at least return if some unsupported call is made to ROM)
+ for (i=0xEA31; i<0xEA7E; ++i) C64->ROMbanks[i] = 0xEA; //NOP (full IRQ-return leading to simple IRQ-return without other tasks)
+ for (i=0; i<9; ++i) C64->ROMbanks [0xEA7E + i] = ROM_IRQreturnCode[i];
+ for (i=0; i<4; ++i) C64->ROMbanks [0xFE43 + i] = ROM_NMIstartCode[i];
+ for (i=0; i<19; ++i) C64->ROMbanks[0xFF48 + i] = ROM_IRQBRKstartCode[i];
+
+ C64->ROMbanks[0xFFFB] = 0xFE; C64->ROMbanks[0xFFFA] = 0x43; //ROM NMI-vector
+ C64->ROMbanks[0xFFFF] = 0xFF; C64->ROMbanks[0xFFFE] = 0x48; //ROM IRQ-vector
+
+ //copy KERNAL & BASIC ROM contents into the RAM under them? (So PSIDs that don't select bank correctly will work better.)
+ for (i=0xA000; i<0x10000; ++i) C64->RAMbank[i]=C64->ROMbanks[i];
+}
+
+
+void cRSID_initMem (cRSID_C64instance* C64) { //set default values that normally KERNEL ensures after startup/reset (only SID-playback related)
+ static int i;
+
+ //data required by both PSID and RSID (according to HVSC SID_file_format.txt):
+ cRSID_writeMemC64( C64, 0x02A6, C64->VideoStandard  ); //$02A6 should be pre-set to: 0:NTSC / 1:PAL
+ cRSID_writeMemC64( C64, 0x0001, 0x37 ); //initialize bank-reg. (ROM-banks and IO enabled)
+
+ //if (C64->ROMbanks[0xE000]==0) { //wasn't a KERNAL-ROM loaded? (e.g. PSID)
+  cRSID_writeMemC64( C64, 0x00CB, 0x40 ); //Some tunes might check for keypress here (e.g. Master Blaster Intro)
+  //if(C64->RealSIDmode) {
+   cRSID_writeMemC64( C64, 0x0315, 0xEA ); cRSID_writeMemC64( C64, 0x0314, 0x31 ); //IRQ
+   cRSID_writeMemC64( C64, 0x0319, 0xEA/*0xFE*/ ); cRSID_writeMemC64( C64, 0x0318, 0x81/*0x47*/ ); //NMI
+  //}
+
+  for (i=0xD000; i<0xD7FF; ++i) C64->IObankRD[i] = C64->IObankWR[i] = 0; //initialize the whole IO area for a known base-state
+  if(C64->RealSIDmode) {C64->IObankWR[0xD012] = 0x37; C64->IObankWR[0xD011] = 0x8B;} //else C64->IObankWR[0xD012] = 0;
+  //C64->IObankWR[0xD019] = 0; //PSID: rasterrow: any value <= $FF, IRQ:enable later if there is VIC-timingsource
+
+  C64->IObankRD[0xDC00]=0x10; C64->IObankRD[0xDC01]=0xFF; //Imitate CIA1 keyboard/joy port, some tunes check if buttons are not pressed
+  if (C64->VideoStandard) { C64->IObankWR[0xDC04]=0x24; C64->IObankWR[0xDC05]=0x40; } //initialize CIAs
+  else { C64->IObankWR[0xDC04]=0x95; C64->IObankWR[0xDC05]=0x42; }
+  if(C64->RealSIDmode) C64->IObankWR[0xDC0D] = 0x81; //Reset-default, but for PSID CIA1 TimerA IRQ should be enabled anyway if SID is CIA-timed
+  C64->IObankWR[0xDC0E] = 0x01; //some tunes (and PSID doc) expect already running CIA (Reset-default)
+  C64->IObankWR[0xDC0F] = 0x00; //All counters other than CIA1 TimerA should be disabled and set to 0xFF for PSID:
+  C64->IObankWR[0xDD04] = C64->IObankWR[0xDD05] = 0xFF; //C64->IObankWR[0xDD0E] = C64->IObank[0xDD0F] = 0x00;
+ //}
+
+}
+