Ticket #17867: sbsound.c

#include "sbsound.h"

/*
Subj:  Re:AdamS60982
Date:  94-04-17 20:38:07 EDT
From:  AdamS60982

I couldn//t really recommend any SB books since I don//t have any.  :)
About the FM, the following example is the best I could find that uses the
information found in the SB
 SBSOUND.BAS by Brett Levin 1992                     
                                                        
  These routines were made entirely from a pretty detailed(techie, but

not that I mind <G>) text file on programming the FM ports on the AdLib/SB.

  You are free to use this in any program what so ever, as long as you

give credit where credit is due.. (stole that line from Rich!) :)
*/

                                                                                //DEFINT A-Z
int DetectCard(void);                                   //DECLARE FUNCTION DetectCard% ()
void SBInit(void);                                              //DECLARE SUB SBInit ()
void WriteReg(short Reg, short Value);  //DECLARE SUB WriteReg (Reg%, Value%)
void SBPlay(short freq);                                //DECLARE SUB SBPlay (freq%)
uint8_t inb(uint16_t port);
void outb(uint16_t port, uint8_t val);
extern void puts(char * str);
                                                        
//CONST false = 0, true = NOT false

//SCREEN 0: CLS

void SoundTest(void){
        /*                                                           
        IF DetectCard = true THEN
          PRINT "AdLib-compatible sound card detected."
        ELSE
          PRINT "Unable to find/detect sound card."
          BEEP
          SYSTEM
        END IF
        PRINT " Initalizing..."
        */

/*
        if (DetectCard()){
                puts("AdLib-compatible sound card detected.\r\n\0");
        }
        else
        {
                puts("Unable to find/detect sound card.\r\n\0");
                //beep();
                return;
        }


        puts(" Initalizing...\r\n\0");
        SBInit();
        puts(" Done.\r\n\0");
*/

        for(int nt = 0; nt<256; ++nt){          //FOR nt = 0 TO 255
                SBPlay(nt);
        }                                                                       //NEXT nt

        puts("\r\nThese routines only support one channel/voice of the FM chip, but\r\n\0");
        puts("eventually I may fix them so you can have a bunch o'instruments on\r\n\0");
        puts("at once.  I'd also like to write a replacement for SBFMDRV.COM, but\r\n\0");
        puts("that's far off, and probably not in QB anyway. This is too fast\r\n\0");
        puts("compiled, so if you are going to use it in anything, add a delay.\r\n\0");
        puts("                                  Enjoy!         -Brett 11 / 12 / 92\r\n\0");


        for(int nt = 255; nt>-1; --nt){         //FOR nt = 255 TO 0 STEP -1
                SBPlay(nt);
        }                                                                       //NEXT nt

//      puts("[Press any key to end]\r\n\0");
        //SLEEP

        WriteReg(0xB0, 0x0);                            //Makes sure no extra sound is left playing
        
        return;
}


int DetectCard(void){
                                                                        
//  Purpose:   Detects an AdLib-compatible card.          
//             Returns -1 (true) if detected and 0 (false) if not.
//  Variables: Nope                                       
                                       
        WriteReg(0x4, 0x60);
        WriteReg(0x4, 0x80);

        int B = inb(0x388);

        WriteReg(0x2, 0xFF);
        WriteReg(0x4, 0x21);

        for (int x = 0; x <= 130; ++x){         // FOR x = 0 TO 130
                int a = inb(0x388);
        }                                                                       // NEXT x

        int C = inb(0x388);

        WriteReg(0x4, 0x60);
        WriteReg(0x4, 0x80);

        if ((B & 0xE0) == 0x00) {
                if ((C & 0xE0) == 0xC0) {
                        return -1;
                }
        }

        return 0;
}

void SBInit(void){
//  Initialize the sound card                             
//(This is the "quick-and-dirty" method; what it//s doing is zeroing out
//  all of the card//s registers.  I haven//t had any problems with this.)

        for(int q = 0; q < 0xF6; ++q){  //FOR q = 1 TO &HF5
                WriteReg(q, 0);
        }                                                               //NEXT q
        
        return;
}

void WriteReg(short Reg, short Value){
//  Purpose:   Writes to any of the SB/AdLib//s registers  
//  Variables: Reg%: Register number,                     
//             Value%: Value to insert in register        
//              (Note: The registers are from 00-F5 (hex))

        outb(0x388, Reg);                               //388h = address/status port, 389h = dataport
        for(int x = 0; x <= 5; ++x){    // This tells the SB what register we want to write to
                inb(0x388);                                     // After we write to the address port we must wait 3.3ms
        }
                                                        
        outb(0x389, Value);                             // Send the value for the register to 389h
        for(int x = 0; x <= 34; ++x){   // Here we must also wait, this time 23ms
                inb(0x388);
        }
        
        return;
}

void SBPlay(short freq){
//  Purpose:      Plays a note                            
//  Variables:    freq% - Frequency (00-FF hex)           
//                duration% - Duration (n seconds) (not used)
//  I//m still working on this part, it may be ugly, but it works <g>.

//  The first group of WriteRegs is the modulator, the second is the

//  carrier.                                              
//  If you just want to know how to create your own instrument, play around

//  with the second values in the first four calls to WriteReg in each group.

//  :-)  Have fun!  - Brett                               
                                                            
        WriteReg(0x20, 0x7);    // Set modulator's multiple to F
        WriteReg(0x40, 0xF);    // Set modulator's level to 40 dB
        WriteReg(0x60, 0xF0);   // Modulator attack: quick, decay: long

        WriteReg(0x80, 0xF0);   // Modulator sustain: medium, release: medium
        WriteReg(0xA0, freq);
                                                                        
                                                                        
        WriteReg(0x23, 0xF);    // Set carrier's multiple to 0 
        WriteReg(0x43, 0x0);    // Set carrier's level to 0 dB 
        WriteReg(0x63, 0xF0);   // Carrier attack: quick, decay: long

        WriteReg(0x83, 0xFF);   // Carrier sustain: quick, release: quick
        WriteReg(0xB0, 0x20);   // Octave                      
                                                                        
        WriteReg(0xE0, 0x0);    // Waveform argument for Tom.. 
                                                        // &H00 is the default, but I felt like
                                                        // dropping it in for you.. :) 
                                                            
// I originally had an extra argument, duration!, but for some reason
// I wanted to do the timing outside of this sub..  You can change it back

// if needs require..                                     
                                                            
//TimeUp! = TIMER + duation!                              
//WHILE TimeUp! > TIMER: WEND  // Worst you can be off is .182 of a second

        return;

}

uint8_t inb(uint16_t port)
{
    uint8_t ret;
    __asm__ volatile ( "inb %1, %0"
                   : "=a"(ret)
                   : "Nd"(port) );
    return ret;
}

void outb(uint16_t port, uint8_t val)
{
    __asm__ volatile ( "outb %0, %1" : : "a"(val), "Nd"(port) );
    /* There's an outb %al, $imm8  encoding, for compile-time constant port numbers that fit in 8b.  (N constraint).
     * Wider immediate constants would be truncated at assemble-time (e.g. "i" constraint).
     * The  outb  %al, %dx  encoding is the only option for all other cases.
     * %1 expands to %dx because  port  is a uint16_t.  %w1 could be used if we had the port number a wider C type */
}