Some cleanup, implementing IRQ and DMA channel register update

src/sound/snd_ess.c

@@ -6,16 +6,20 @@
  *
  *           This file is part of the 86Box distribution.
  *
- *           Sound Blaster emulation.
+ *           ESS AudioDrive emulation.
  *
  *
  *
  * Authors:  Sarah Walker, <https://pcem-emulator.co.uk/>
  *           Miran Grca, <mgrca8@gmail.com>
  *           TheCollector1995, <mariogplayer@gmail.com>
+ *           Cacodemon345, 
+ *           Kagamiin~, <kagamiin@riseup.net>
  *
  *           Copyright 2008-2020 Sarah Walker.
  *           Copyright 2016-2020 Miran Grca.
+ *           Copyright 2024 Cacodemon345
+ *           Copyright 2024 Kagamiin~
  */
 #include <stdarg.h>
 #include <stdint.h>
@@ -79,7 +83,7 @@ typedef struct ess_mixer_t {
     uint8_t regs[256];
 
     uint8_t ess_id_str[256];
-    uint8_t ess_id_str_pos : 2;
+    uint8_t ess_id_str_pos;
 } ess_mixer_t;
 
 typedef struct ess_t {
@@ -130,7 +134,10 @@ ess_mixer_write(uint16_t addr, uint8_t val, void *priv)
         mixer->index      = val;
         mixer->regs[0x01] = val;
         if (val == 0x40)
+        {
+            pclog("ess: Mixer addr 0x40 selected, ID string offset reset\n");
             mixer->ess_id_str_pos = 0;
+        }
     } else {
         if (mixer->index == 0) {
             /* Reset */
@@ -151,7 +158,7 @@ ess_mixer_write(uint16_t addr, uint8_t val, void *priv)
             sb_dsp_set_stereo(&ess->dsp, mixer->regs[0x0e] & 2);
         } else {
             mixer->regs[mixer->index] = val;
-            pclog("ess: Register WRITE: %02X\t%02X\n", mixer->index, mixer->regs[mixer->index]);
+            pclog("ess: Mixer Register WRITE: %02X\t%02X\n", mixer->index, mixer->regs[mixer->index]);
 
             switch (mixer->index) {
                 /* Compatibility: chain registers 0x02 and 0x22 as well as 0x06 and 0x26 */
@@ -198,23 +205,27 @@ ess_mixer_write(uint16_t addr, uint8_t val, void *priv)
                     break;
 
                 case 0x40: {
-                        break;
+                        /* TODO: Implement "Read-Sequence-Key" method of software address selection
-                        uint16_t mpu401_base_addr = 0x300 | ((mixer->regs[0x40] & 0x38) << 1);
+                         * (needed for ESSCFG.EXE to work properly) */
-                        gameport_remap(ess->gameport, !(mixer->regs[0x40] & 0x2) ? 0x00 : 0x200);
-                        /* This doesn't work yet. */
-                        /*
-                        io_removehandler(0x0388, 0x0004,
-                        ess->opl.read, NULL, NULL,
-                        ess->opl.write, NULL, NULL,
-                        ess->opl.priv);
-                        if (mixer->regs[0x40] & 1) {
-                            io_sethandler(0x0388, 0x0004,
-                                        ess->opl.read, NULL, NULL,
-                                        ess->opl.write, NULL, NULL,
-                                        ess->opl.priv);
-                        }*/
 
-                        switch ((mixer->regs[0x40] >> 5) & 7) {
+                        uint16_t mpu401_base_addr = 0x300 | ((mixer->regs[0x40] << 1) & 0x30);
+                        gameport_remap(ess->gameport, !(mixer->regs[0x40] & 0x2) ? 0x00 : 0x200);
+
+                        /* This doesn't work yet. */
+#if 1
+                        io_removehandler(0x0388, 0x0004,
+                                         ess->opl.read, NULL, NULL,
+                                         ess->opl.write, NULL, NULL,
+                                         ess->opl.priv);
+                        if ((mixer->regs[0x40] & 0x1) != 0)
+                        {
+                            io_sethandler(0x0388, 0x0004,
+                                          ess->opl.read, NULL, NULL,
+                                          ess->opl.write, NULL, NULL,
+                                          ess->opl.priv);
+                        }
+#endif
+                        switch ((mixer->regs[0x40] >> 5) & 0x7) {
                             case 0:
                                 mpu401_change_addr(ess->mpu, 0x00);
                                 mpu401_setirq(ess->mpu, -1);
@@ -252,7 +263,7 @@ ess_mixer_write(uint16_t addr, uint8_t val, void *priv)
                     }
 
                 default:
-                    pclog("ess: Unknown register WRITE: %02X\t%02X\n", mixer->index, mixer->regs[mixer->index]);
+                    pclog("ess: Unknown mixer register WRITE: %02X\t%02X\n", mixer->index, mixer->regs[mixer->index]);
                     break;
             }
         }
@@ -320,21 +331,22 @@ ess_mixer_read(uint16_t addr, void *priv)
         case 0x36:
         case 0x38:
         case 0x3e:
-            pclog("ess: Register READ: %02X\t%02X\n", mixer->index, mixer->regs[mixer->index]);
+            pclog("ess: Mixer Register READ: %02X\t%02X\n", mixer->index, mixer->regs[mixer->index]);
             return mixer->regs[mixer->index];
 
         case 0x40:
             {
                 uint8_t val = mixer->ess_id_str[mixer->ess_id_str_pos];
+                uint8_t pos_log = mixer->ess_id_str_pos; /* TODO remove */
                 mixer->ess_id_str_pos++;
                 if (mixer->ess_id_str_pos >= 4)
                     mixer->ess_id_str_pos = 0;
-                pclog("ess: ID READ: %02X (pos %d)\n", val, mixer->ess_id_str_pos);
+                pclog("ess: ID READ: %02X (pos %d)\n", val, pos_log);
                 return val;
             }
 
         default:
-            pclog("ess: Unknown register READ: %02X\t%02X\n", mixer->index, mixer->regs[mixer->index]);
+            pclog("ess: Unknown mixer register READ: %02X\t%02X\n", mixer->index, mixer->regs[mixer->index]);
             break;
     }
 
@@ -491,7 +503,7 @@ ess_1688_init(UNUSED(const device_t *info))
     }
 
     ess->mpu = (mpu_t *) calloc(1, sizeof(mpu_t));
-    mpu401_init(ess->mpu, 0, 0, M_UART, 1);
+    mpu401_init(ess->mpu, 0, -1, M_UART, 1);
     sb_dsp_set_mpu(&ess->dsp, ess->mpu);
 
     ess->gameport = gameport_add(&gameport_pnp_device);
@@ -620,4 +632,4 @@ const device_t ess_1688_device = {
     .speed_changed = ess_speed_changed,
     .force_redraw  = NULL,
     .config        = ess_config
-};
+};

src/sound/snd_sb_dsp.c

@@ -582,6 +582,37 @@ sb_16_write_dma(void *priv, uint16_t val)
     return ret;
 }
 
+void
+sb_ess_update_irq_drq_readback_regs(sb_dsp_t *dsp, bool legacy)
+{
+    uint8_t t = 0x00;
+    /* IRQ control */
+    if (legacy)
+    {
+        t |= 0x80;
+    }
+    switch (dsp->sb_irqnum) {
+        case 5:     t |= 0x5; break;
+        case 7:     t |= 0xA; break;
+        case 10:    t |= 0xF; break;
+    }
+    pclog("ESSreg 0xB1 was %02X, irqnum is %d, t is %02X; new 0xB1 is %02X\n", ESSreg(0xB1), dsp->sb_irqnum, t, (ESSreg(0xB1) & 0xF0) | t);
+    ESSreg(0xB1) = (ESSreg(0xB1) & 0xF0) | t;
+
+    /* DRQ control */
+    t = 0x00;
+    if (legacy)
+    {
+        t |= 0x80;
+    }
+    switch (dsp->sb_8_dmanum) {
+        case 0:     t |= 0x5; break;
+        case 1:     t |= 0xA; break;
+        case 3:     t |= 0xF; break;
+    }
+    ESSreg(0xB2) = (ESSreg(0xB2) & 0xF0) | t;
+}
+
 void
 sb_dsp_setirq(sb_dsp_t *dsp, int irq)
 {
@@ -589,23 +620,7 @@ sb_dsp_setirq(sb_dsp_t *dsp, int irq)
     sb_dsp_log("IRQ now: %i\n", irq);
     dsp->sb_irqnum = irq;
 
-    /* legacy audio interrupt control */
+    sb_ess_update_irq_drq_readback_regs(dsp, true);
-    t = 0x80;/*game compatible IRQ*/
-    switch (dsp->sb_irqnum) {
-        case 5:     t |= 0x5; break;
-        case 7:     t |= 0xA; break;
-        case 10:    t |= 0xF; break;
-    }
-    ESSreg(0xB1) = t;
-
-    /* DRQ control */
-    t = 0x80;/*game compatible DRQ */
-    switch (dsp->sb_8_dmanum) {
-        case 0:     t |= 0x5; break;
-        case 1:     t |= 0xA; break;
-        case 3:     t |= 0xF; break;
-    }
-    ESSreg(0xB2) = t;
 }
 
 void
@@ -615,23 +630,7 @@ sb_dsp_setdma8(sb_dsp_t *dsp, int dma)
     sb_dsp_log("8-bit DMA now: %i\n", dma);
     dsp->sb_8_dmanum = dma;
 
-    /* legacy audio interrupt control */
+    sb_ess_update_irq_drq_readback_regs(dsp, true);
-    t = 0x80;/*game compatible IRQ*/
-    switch (dsp->sb_irqnum) {
-        case 5:     t |= 0x5; break;
-        case 7:     t |= 0xA; break;
-        case 10:    t |= 0xF; break;
-    }
-    ESSreg(0xB1) = t;
-
-    /* DRQ control */
-    t = 0x80;/*game compatible DRQ */
-    switch (dsp->sb_8_dmanum) {
-        case 0:     t |= 0x5; break;
-        case 1:     t |= 0xA; break;
-        case 3:     t |= 0xF; break;
-    }
-    ESSreg(0xB2) = t;
 }
 
 void
@@ -686,6 +685,7 @@ static uint8_t sb_ess_read_reg(sb_dsp_t *dsp, uint8_t reg)
 {
     switch (reg) {
         default:
+            pclog("ESS register read reg=%02xh val=%02xh\n",reg, ESSreg(reg));
             return ESSreg(reg);
     }
 
@@ -752,9 +752,43 @@ static void sb_ess_write_reg(sb_dsp_t *dsp, uint8_t reg, uint8_t data)
             break;
 
         case 0xB1: /* Legacy Audio Interrupt Control */
+            ESSreg(reg) = (ESSreg(reg) & 0x0F) + (data & 0xF0); // lower 4 bits not writeable
+            switch (data & 0x0C)
+            {
+            case 0x00:
+                dsp->sb_irqnum = 2;
+                break;
+            case 0x04:
+                dsp->sb_irqnum = 5;
+                break;
+            case 0x08:
+                dsp->sb_irqnum = 7;
+                break;
+            case 0x0C:
+                dsp->sb_irqnum = 10;
+                break;
+            }
+            sb_ess_update_irq_drq_readback_regs(dsp, false);
+            break;
         case 0xB2: /* DRQ Control */
             chg = ESSreg(reg) ^ data;
             ESSreg(reg) = (ESSreg(reg) & 0x0F) + (data & 0xF0); // lower 4 bits not writeable
+            switch (data & 0x0C)
+            {
+            case 0x00:
+                dsp->sb_8_dmanum = -1;
+                break;
+            case 0x04:
+                dsp->sb_8_dmanum = 0;
+                break;
+            case 0x08:
+                dsp->sb_8_dmanum = 1;
+                break;
+            case 0x0C:
+                dsp->sb_8_dmanum = 3;
+                break;
+            }
+            sb_ess_update_irq_drq_readback_regs(dsp, false);
             if (chg & 0x40) sb_ess_update_dma_status(dsp);
             break;
         case 0xB5: /* DAC Direct Access Holding (low) */