foxbox/lib/rbcodec/codecs/cRSID/libcRSID.c

// cRSID lightweight (integer-only) RealSID library (with API-calls) by Hermit (Mihaly Horvath), Year 2022
// License: WTF - do what the fuck you want with the code, but please mention me as the original author

#include <stdlib.h>
//#include <stdint.h>
#ifdef CRSID_PLATFORM_PC
 #include <stdio.h>
#endif

#include "libcRSID.h"

#include "C64/C64.c"
#include "host/file.c"
#include "host/audio.c"


cRSID_C64instance* cRSID_init (unsigned short samplerate, unsigned short buflen) {
 static cRSID_C64instance* C64 = &cRSID_C64;

 C64 = cRSID_createC64 (C64, samplerate);
#ifdef CRSID_PLATFORM_PC
 if ( cRSID_initSound (C64, samplerate,buflen) == NULL) return NULL;
#else
 if (buflen) return C64; //this is here just to eliminate unused 'buflen' variable warning
#endif

 return C64;
}


void cRSID_initSIDtune (cRSID_C64instance* C64, cRSID_SIDheader* SIDheader, char subtune) { //subtune: 1..255
 static const unsigned char PowersOf2[] = {0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80};
 unsigned int InitTimeout=10000000; //allowed instructions, value should be selected to allow for long-running memory-copiers in init-routines (e.g. Synth Sample)

 if (subtune==0) subtune = 1;
 else if (subtune > SIDheader->SubtuneAmount) subtune = SIDheader->SubtuneAmount;
 C64->SubTune = subtune;

 cRSID_setC64(C64); cRSID_initC64(C64); //cRSID_writeMemC64(C64,0xD418,0xF); //set C64 hardware and init (reset) it

 //determine init-address:
 C64->InitAddress = ((SIDheader->InitAddressH)<<8) + (SIDheader->InitAddressL); //get info from BASIC-startupcode for some tunes
 if (C64->RAMbank[1] == 0x37) { //are there SIDs with routine under IO area? some PSIDs don't set bank-registers themselves
  if ( (0xA000 <= C64->InitAddress && C64->InitAddress < 0xC000)
       || (C64->LoadAddress < 0xC000 && C64->EndAddress >= 0xA000) ) C64->RAMbank[1] = 0x36;
  else if (C64->InitAddress >= 0xE000 || C64->EndAddress >=0xE000) C64->RAMbank[1] = 0x35;
 }
 cRSID_initCPU( &C64->CPU, C64->InitAddress ); //prepare init-routine call
 C64->CPU.A = subtune - 1;

 if (!C64->RealSIDmode) {
  //call init-routine:
  for (InitTimeout=10000000; InitTimeout>0; InitTimeout--) { if ( cRSID_emulateCPU()>=0xFE ) break; } //give error when timed out?
 }

 //determine timing-source, if CIA, replace FrameCycles previouisly set to VIC-timing
 if (subtune>32) C64->TimerSource = C64->SIDheader->SubtuneTimeSources[0] & 0x80; //subtunes above 32 should use subtune32's timing
 else C64->TimerSource = C64->SIDheader->SubtuneTimeSources[(32-subtune)>>3] & PowersOf2[(subtune-1)&7];
 if (C64->TimerSource || C64->IObankWR[0xDC05]!=0x40 || C64->IObankWR[0xDC04]!=0x24) { //CIA1-timing (probably multispeed tune)
  C64->FrameCycles = ( ( C64->IObankWR[0xDC04] + (C64->IObankWR[0xDC05]<<8) ) ); //<< 4) / C64->ClockRatio;
  C64->TimerSource = 1; //if init-routine changed DC04 or DC05, assume CIA-timing
 }

 //determine playaddress:
 C64->PlayAddress = (SIDheader->PlayAddressH<<8) + SIDheader->PlayAddressL;
 if (C64->PlayAddress) { //normal play-address called with JSR
  if (C64->RAMbank[1] == 0x37) { //are there SIDs with routine under IO area?
   if (0xA000 <= C64->PlayAddress && C64->PlayAddress < 0xC000) C64->RAMbank[1] = 0x36;
  }
  else if (C64->PlayAddress >= 0xE000) C64->RAMbank[1] = 0x35; //player under KERNAL (e.g. Crystal Kingdom Dizzy)
 }
 else { //IRQ-playaddress for multispeed-tunes set by init-routine (some tunes turn off KERNAL ROM but doesn't set IRQ-vector!)
  C64->PlayAddress = (C64->RAMbank[1] & 3) < 2 ? cRSID_readMemC64(C64,0xFFFE) + (cRSID_readMemC64(C64,0xFFFF)<<8) //for PSID
                                                 : cRSID_readMemC64(C64,0x314) + (cRSID_readMemC64(C64,0x315)<<8);
  if (C64->PlayAddress==0) { //if 0, still try with RSID-mode fallback
   cRSID_initCPU( &C64->CPU, C64->PlayAddress ); //point CPU to play-routine
   C64->Finished=1; C64->Returned=1; return;
  }
 }

 if (!C64->RealSIDmode) {  //prepare (PSID) play-routine playback:
  cRSID_initCPU( &C64->CPU, C64->PlayAddress ); //point CPU to play-routine
  C64->FrameCycleCnt=0; C64->Finished=1; C64->SampleCycleCnt=0; //C64->CIAisSet=0;
 }
 else { C64->Finished=0; C64->Returned=0; }

}


#ifdef CRSID_PLATFORM_PC


char cRSID_playSIDfile(cRSID_C64instance* C64, char* filename, char subtune) {
 static cRSID_SIDheader* SIDheader;

 SIDheader = cRSID_loadSIDtune(C64,filename);
 if (SIDheader==NULL) return CRSID_ERROR_LOAD;

 cRSID_initSIDtune (C64 , SIDheader , subtune);
 cRSID_playSIDtune ();

 return CRSID_STATUS_OK;
}


cRSID_SIDheader* cRSID_loadSIDtune(cRSID_C64instance* C64, char* filename) {
 enum SIDspecs { CRSID_FILESIZE_MAX = 100000 };
 int FileSize;
 static unsigned char SIDfileData [CRSID_FILESIZE_MAX]; //use memset?

 FileSize = cRSID_loadSIDfile( SIDfileData, filename, CRSID_FILESIZE_MAX);
 if ( FileSize == CRSID_ERROR_LOAD ) return NULL;

 return cRSID_processSIDfile ( C64, SIDfileData, FileSize );
}


void cRSID_close() {
 cRSID_closeSound();
}


void cRSID_playSIDtune (void) {
 cRSID_startSound();
}


void cRSID_pauseSIDtune (void) {
 cRSID_stopSound();
}


#endif