87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
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///////////////////////////////////////////////////////////////////////////
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//
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// SDL_CheckSB() - Checks to see if a SoundBlaster resides at a
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// particular I/O location
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//
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///////////////////////////////////////////////////////////////////////////
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static boolean
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SDL_CheckSB(int port)
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{
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int i;
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sbLocation = port << 4; // Initialize stuff for later use
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sbOut(sbReset,true); // Reset the SoundBlaster DSP
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asm mov dx,0x388 // Wait >4usec
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asm in al, dx
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asm in al, dx
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asm in al, dx
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asm in al, dx
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asm in al, dx
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asm in al, dx
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asm in al, dx
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asm in al, dx
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asm in al, dx
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sbOut(sbReset,false); // Turn off sb DSP reset
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asm mov dx,0x388 // Wait >100usec
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asm mov cx,100
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usecloop:
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asm in al,dx
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asm loop usecloop
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for (i = 0;i < 100;i++)
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{
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if (sbIn(sbDataAvail) & 0x80) // If data is available...
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{
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if (sbIn(sbReadData) == 0xaa) // If it matches correct value
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return(true);
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else
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{
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sbLocation = -1; // Otherwise not a SoundBlaster
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return(false);
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}
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}
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}
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sbLocation = -1; // Retry count exceeded - fail
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return(false);
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}
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///////////////////////////////////////////////////////////////////////////
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//
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// Checks to see if a SoundBlaster is in the system. If the port passed is
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// -1, then it scans through all possible I/O locations. If the port
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// passed is 0, then it uses the default (2). If the port is >0, then
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// it just passes it directly to SDL_CheckSB()
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//
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///////////////////////////////////////////////////////////////////////////
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static boolean
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SDL_DetectSoundBlaster(int port)
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{
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int i;
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if (port == 0) // If user specifies default, use 2
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port = 2;
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if (port == -1)
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{
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if (SDL_CheckSB(2)) // Check default before scanning
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return(true);
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if (SDL_CheckSB(4)) // Check other SB Pro location before scan
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return(true);
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for (i = 1;i <= 6;i++) // Scan through possible SB locations
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{
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if ((i == 2) || (i == 4))
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continue;
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if (SDL_CheckSB(i)) // If found at this address,
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return(true); // return success
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}
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return(false); // All addresses failed, return failure
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}
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else
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return(SDL_CheckSB(port)); // User specified address or default
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}
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