Move register read/write code into OPL library. Detect OPL in the

library code, so that we fall back to software emulation if we have port
access but an OPL is not detected. Fix detection of ioperm in configure.

Subversion-branch: /branches/opl-branch
Subversion-revision: 1692

1 files changed, 12 insertions, 166 deletions

diff --git a/src/i_oplmusic.c b/src/i_oplmusic.c
index dd62076d..e9e722e4 100644
--- a/src/i_oplmusic.c
+++ b/src/i_oplmusic.c
@@ -326,149 +326,11 @@ static unsigned int num_tracks;
 static unsigned int running_tracks = 0;
 static boolean song_looping;
 
-// In the initialisation stage, register writes are spaced by reading
-// from the register port (0).  After initialisation, spacing is
-// peformed by reading from the data port instead.  I have no idea
-// why.
-
-static boolean init_stage_reg_writes = false;
-
 // Configuration file variable, containing the port number for the
 // adlib chip.
 
 int opl_io_port = 0x388;
 
-static unsigned int GetStatus(void)
-{
-    return OPL_ReadPort(OPL_REGISTER_PORT);
-}
-
-// Write an OPL register value
-
-static void WriteRegister(int reg, int value)
-{
-    int i;
-
-    OPL_WritePort(OPL_REGISTER_PORT, reg);
-
-    // For timing, read the register port six times after writing the
-    // register number to cause the appropriate delay
-
-    for (i=0; i<6; ++i)
-    {
-        // An oddity of the Doom OPL code: at startup initialisation,
-        // the spacing here is performed by reading from the register
-        // port; after initialisation, the data port is read, instead.
-
-        if (init_stage_reg_writes)
-        {
-            OPL_ReadPort(OPL_REGISTER_PORT);
-        }
-        else
-        {
-            OPL_ReadPort(OPL_DATA_PORT);
-        }
-    }
-
-    OPL_WritePort(OPL_DATA_PORT, value);
-
-    // Read the register port 25 times after writing the value to
-    // cause the appropriate delay
-
-    for (i=0; i<24; ++i)
-    {
-        GetStatus();
-    }
-}
-
-// Detect the presence of an OPL chip
-
-static boolean DetectOPL(void)
-{
-    int result1, result2;
-    int i;
-
-    // Reset both timers:
-    WriteRegister(OPL_REG_TIMER_CTRL, 0x60);
-
-    // Enable interrupts:
-    WriteRegister(OPL_REG_TIMER_CTRL, 0x80);
-
-    // Read status
-    result1 = GetStatus();
-
-    // Set timer:
-    WriteRegister(OPL_REG_TIMER1, 0xff);
-
-    // Start timer 1:
-    WriteRegister(OPL_REG_TIMER_CTRL, 0x21);
-
-    // Wait for 80 microseconds
-    // This is how Doom does it:
-
-    for (i=0; i<200; ++i)
-    {
-        GetStatus();
-    }
-
-    OPL_Delay(1);
-
-    // Read status
-    result2 = GetStatus();
-
-    // Reset both timers:
-    WriteRegister(OPL_REG_TIMER_CTRL, 0x60);
-
-    // Enable interrupts:
-    WriteRegister(OPL_REG_TIMER_CTRL, 0x80);
-
-    return (result1 & 0xe0) == 0x00
-        && (result2 & 0xe0) == 0xc0;
-}
-
-// Initialise registers on startup
-
-static void InitRegisters(void)
-{
-    int r;
-
-    // Initialise level registers
-
-    for (r=OPL_REGS_LEVEL; r <= OPL_REGS_LEVEL + OPL_NUM_OPERATORS; ++r)
-    {
-        WriteRegister(r, 0x3f);
-    }
-
-    // Initialise other registers
-    // These two loops write to registers that actually don't exist,
-    // but this is what Doom does ...
-    // Similarly, the <= is also intenational.
-
-    for (r=OPL_REGS_ATTACK; r <= OPL_REGS_WAVEFORM + OPL_NUM_OPERATORS; ++r)
-    {
-        WriteRegister(r, 0x00);
-    }
-
-    // More registers ...
-
-    for (r=1; r < OPL_REGS_LEVEL; ++r)
-    {
-        WriteRegister(r, 0x00);
-    }
-
-    // Re-initialise the low registers:
-
-    // Reset both timers and enable interrupts:
-    WriteRegister(OPL_REG_TIMER_CTRL,      0x60);
-    WriteRegister(OPL_REG_TIMER_CTRL,      0x80);
-
-    // "Allow FM chips to control the waveform of each operator":
-    WriteRegister(OPL_REG_WAVEFORM_ENABLE, 0x20);
-
-    // Keyboard split point on (?)
-    WriteRegister(OPL_REG_FM_MODE,         0x40);
-}
-
 // Load instrument table from GENMIDI lump:
 
 static boolean LoadInstrumentTable(void)
@@ -584,11 +446,11 @@ static void LoadOperatorData(int operator, genmidi_op_t *data,
         level |= 0x3f;
     }
 
-    WriteRegister(OPL_REGS_LEVEL + operator, level);
-    WriteRegister(OPL_REGS_TREMOLO + operator, data->tremolo);
-    WriteRegister(OPL_REGS_ATTACK + operator, data->attack);
-    WriteRegister(OPL_REGS_SUSTAIN + operator, data->sustain);
-    WriteRegister(OPL_REGS_WAVEFORM + operator, data->waveform);
+    OPL_WriteRegister(OPL_REGS_LEVEL + operator, level);
+    OPL_WriteRegister(OPL_REGS_TREMOLO + operator, data->tremolo);
+    OPL_WriteRegister(OPL_REGS_ATTACK + operator, data->attack);
+    OPL_WriteRegister(OPL_REGS_SUSTAIN + operator, data->sustain);
+    OPL_WriteRegister(OPL_REGS_WAVEFORM + operator, data->waveform);
 }
 
 // Set the instrument for a particular voice.
@@ -629,8 +491,8 @@ static void SetVoiceInstrument(opl_voice_t *voice,
     // two operators.  Turn on bits in the upper nybble; I think this
     // is for OPL3, where it turns on channel A/B.
 
-    WriteRegister(OPL_REGS_FEEDBACK + voice->index,
-                  data->feedback | 0x30);
+    OPL_WriteRegister(OPL_REGS_FEEDBACK + voice->index,
+                      data->feedback | 0x30);
 
     // Hack to force a volume update.
 
@@ -669,7 +531,7 @@ static void SetVoiceVolume(opl_voice_t *voice, unsigned int volume)
     {
         voice->reg_volume = reg_volume;
 
-        WriteRegister(OPL_REGS_LEVEL + voice->op2, reg_volume);
+        OPL_WriteRegister(OPL_REGS_LEVEL + voice->op2, reg_volume);
 
         // If we are using non-modulated feedback mode, we must set the
         // volume for both voices.
@@ -679,7 +541,7 @@ static void SetVoiceVolume(opl_voice_t *voice, unsigned int volume)
 
         if ((opl_voice->feedback & 0x01) != 0)
         {
-            WriteRegister(OPL_REGS_LEVEL + voice->op1, reg_volume);
+            OPL_WriteRegister(OPL_REGS_LEVEL + voice->op1, reg_volume);
         }
     }
 }
@@ -731,17 +593,7 @@ static boolean I_OPL_InitMusic(void)
 {
     if (!OPL_Init(opl_io_port))
     {
-        return false;
-    }
-
-    init_stage_reg_writes = true;
-
-    // Doom does the detection sequence twice, for some reason:
-
-    if (!DetectOPL() || !DetectOPL())
-    {
         printf("Dude.  The Adlib isn't responding.\n");
-        OPL_Shutdown();
         return false;
     }
 
@@ -753,14 +605,8 @@ static boolean I_OPL_InitMusic(void)
         return false;
     }
 
-    InitRegisters();
     InitVoices();
 
-    // Now that initialisation has finished, switch the
-    // register writing mode:
-
-    init_stage_reg_writes = false;
-
     music_initialised = true;
 
     return true;
@@ -789,7 +635,7 @@ static void I_OPL_SetMusicVolume(int volume)
 
 static void VoiceKeyOff(opl_voice_t *voice)
 {
-    WriteRegister(OPL_REGS_FREQ_2 + voice->index, voice->freq >> 8);
+    OPL_WriteRegister(OPL_REGS_FREQ_2 + voice->index, voice->freq >> 8);
 }
 
 // Get the frequency that we should be using for a voice.
@@ -947,8 +793,8 @@ static void UpdateVoiceFrequency(opl_voice_t *voice)
 
     if (voice->freq != freq)
     {
-        WriteRegister(OPL_REGS_FREQ_1 + voice->index, freq & 0xff);
-        WriteRegister(OPL_REGS_FREQ_2 + voice->index, (freq >> 8) | 0x20);
+        OPL_WriteRegister(OPL_REGS_FREQ_1 + voice->index, freq & 0xff);
+        OPL_WriteRegister(OPL_REGS_FREQ_2 + voice->index, (freq >> 8) | 0x20);
 
         voice->freq = freq;
     }