Fix double CPU clocks in reads/writes, assuage unused argument in vsuWrite()

Reviewed-on: #1

core/cpu.c

@@ -234,7 +234,7 @@ static int cpuOnExecute(VB *sim) {
     #define VB_ON_READ VB_DIRECT_READ
 #endif
 static int cpuRead(VB *sim, uint32_t address, int type, int32_t *value) {
-    uint32_t cycles = 4; /* TODO: Research this */
+    uint32_t cycles = 0; /* TODO: Research this */
 
     /* Retrieve the value from the simulation state directly */
     busRead(sim, address, type, value);
@@ -289,7 +289,7 @@ static int cpuReadFetch(VB *sim, int fetch, uint32_t address, int32_t *value) {
 #endif
 static int cpuWrite(VB *sim, uint32_t address, int type, int32_t value) {
     int      cancel = 0;
-    uint32_t cycles = 3; /* TODO: Research this */
+    uint32_t cycles = 0; /* TODO: Research this */
 
     /* Reset pseudo-halt */
     if (sim->ph.enabled)

core/vip.c

@@ -984,7 +984,7 @@ static void vipDrawHBias(VB *sim, World *world) {
         /* Process all visible lines */
         param = &sim->vip.ram[world->paramBase +
             ((y1 - world->gy) << 2) + (i << 1)];
-        for (y = y1; y < y2; y++, param += 2) {
+        for (y = y1; y < y2; y++, param += 4) {
 
             /* Configure window bounds */
             wnd.y1 = y;
@@ -992,7 +992,7 @@ static void vipDrawHBias(VB *sim, World *world) {
 
             /* Draw the background into the window */
             vipDrawBackground(sim->vip.shadow[i], &wnd, world,
-                mx + busReadBuffer(param, VB_S16), my);
+                mx - busReadBuffer(param, VB_S16), my);
         }
 
     }

core/vsu.c

@@ -132,14 +132,19 @@ static void vsuEmulateChannel(VB *sim, Channel *chan) {
     }
 
     /* Envelope modification */
-    if (chan->env.enb && !chan->env.modmask && chan->env.clocks == 0) {
+    if (chan->env.clocks == 0) {
+        uint8_t new_envelope = chan->env.value;
         if (chan->env.dir == 0 && chan->env.value != 0)
-            chan->env.value--;
+            new_envelope--;
         else if (chan->env.dir == 1 && chan->env.value != 15)
-            chan->env.value++;
+            new_envelope++;
-        else if (chan->env.rep)
+        else if (chan->env.rep && chan->env.modmask != 2) {
-            chan->env.value = chan->env.reload;
+            new_envelope = chan->env.reload;
-        else chan->env.modmask = 1;
+            chan->env.modmask = 0;
+        } else if (!chan->env.modmask)
+            chan->env.modmask = 1;
+        if (chan->env.enb && !chan->env.modmask)
+            chan->env.value = new_envelope;
         chan->env.clocks = ((uint32_t) chan->env.interval + 1) * 307220;
     }
 
@@ -215,6 +220,7 @@ static void vsuWriteEV0(VB *sim, int index, uint8_t value) {
     chan->env.interval = value      &  7;
     chan->env.value    = value >> 4 & 15;
     chan->env.reload   = chan->env.value;
+    if (chan->env.modmask == 1) chan->env.modmask = 2;
     if (index == 4) {
         chan->freqmod = vsuCheckFreqMod(sim);
         vsuNextFreqMod(sim, chan);
@@ -231,6 +237,12 @@ static void vsuWriteEV1(VB *sim, int index, uint8_t value) {
     /* Parse fields */
     chan->env.enb = value      & 1;
     chan->env.rep = value >> 1 & 1;
+    if (
+        !chan->env.rep && (
+            (chan->env.reload ==  0 && chan->env.dir == 0) ||
+            (chan->env.reload == 15 && chan->env.dir == 1)
+        )
+    ) chan->env.modmask = 1;
 
     /* Processing by channel */
     switch (index) {
@@ -286,7 +298,12 @@ static void vsuWriteINT(VB *sim, int index, uint8_t value) {
     /* Update state */
     chan->int_.clocks = 76805 * ((uint32_t) chan->int_.interval + 1);
     chan->env.modmask = 0;
-    if (chan->env.enb)
+    if (
+        !chan->env.rep && (
+            (chan->env.reload ==  0 && chan->env.dir == 0) ||
+            (chan->env.reload == 15 && chan->env.dir == 1)
+        )
+    ) chan->env.modmask = 1;
     chan->env.clocks = 307220 * ((uint32_t) chan->env.interval + 1);
     if (index != 5) {
         chan->wave.sample = 0;
@@ -377,7 +394,7 @@ static void vsuEmulate(VB *sim, uint32_t clocks) {
 
                     /* Clocks until next state change */
                     chan->until = chan->clocks;
-                    if (chan->env.enb && !chan->env.modmask &&
+                    if (chan->env.enb && chan->env.modmask != 2 &&
                         chan->env.clocks < chan->until)
                         chan->until = chan->env.clocks;
                     if (chan->int_.auto_ && chan->int_.clocks < chan->until)
@@ -387,7 +404,7 @@ static void vsuEmulate(VB *sim, uint32_t clocks) {
 
                     /* Manage clocks */
                     chan->clocks -= chan->until;
-                    if (chan->env.enb && !chan->env.modmask)
+                    if (chan->env.enb && chan->env.modmask != 2)
                         chan->env.clocks -= chan->until;
                     if (chan->int_.auto_)
                         chan->int_.clocks -= chan->until;
@@ -531,14 +548,7 @@ static void vsuReset(VB *sim) {
 
 /* Write a typed value to the VSU bus */
 static void vsuWrite(VB*sim,uint32_t address,int type,int32_t value,int debug){
-
+    (void) type;
-    /* Only byte writes are allowed */
-    switch (type) {
-        case VB_S16:
-        case VB_U16:
-        case VB_S32:
-            return;
-    }
 
     /* Unmapped */
     if (address & 1)