initial CPU board

plugin/Makefile

@@ -12,6 +12,7 @@ NAME = chassis
 FILES_DSP = \
 	parameters.cpp \
 	voicecpu.cpp \
+	cpuboard.cpp \
 	chassis.cpp \
 	voice.cpp
 

plugin/chassis.cpp

@@ -19,6 +19,9 @@
 #include "chassis.hpp"
 
 #include "patches.hpp"
+#include "cpuboard.hpp"
+
+Assigner ic1;
 
 START_NAMESPACE_DISTRHO
 
@@ -61,6 +64,19 @@ void Chassis::deactivate() {
 
 void Chassis::noteOn(uint8_t note) {
     uint32_t i;
+
+    ic1.ram[0x4e] = 0x90;
+    ic1.ram[0x3e] = note;
+
+
+    ic1.noteOn();
+
+    for (uint8_t i=0x40; i<0x4f; i++) {
+        printf("%02x ", ic1.ram[i]);
+    }
+    printf("\n");
+
+
     s.keyon = true;
     for (i = 0; i < NUM_VOICES; i++) {
         vPtr++;

plugin/cpuboard.cpp

@@ -0,0 +1,60 @@
+#include "cpuboard.hpp"
+
+#include <cstdio>
+
+void Assigner::noteOn() {
+
+    // called from serial interrupt handler
+    // sets or clears a bit in the "MIDI Key pressed" bitfield
+
+    // note that RAM addresses normally set to 0xff40 are reduced to 0x0040
+    
+    printf("starting noteon %02x %02x\n", ram[0x4e], ram[0x3e]);
+
+    // 06ca
+    a = ram[0x3e];  // first byte is note value
+    c = 0x40;   // fake velocity
+
+    // bring note into range
+    // 06cc
+    if (a <= 0x17) a += 12;
+    // 06d0
+    if (a >= 0x6d) a -= 12;
+
+    // 06d4 subtract transpose from ffbe
+
+    // 06d7 mov b,a; slr b; slr b; slr b
+    b = a >> 3;
+    a &= 0x07;
+
+    // 06e0 note on?
+    if (ram[0x4e] != 0x90) goto h06f9;  // no, skip to note off
+    // 06e4 velocity zero?
+    if (c == 0) goto h06f9;  // yes, skip to note off
+
+    // otherwise handle note on
+    // 06e8 lxi hl,$0008; ldax (a+hl) for table of bits
+    a = 1 << a;
+    printf("A=%02x\n", a);
+    c = a;
+    hl = 0x0040;        // note bit flags
+    a = ram[hl + b];    // byte pointed to by upper part
+    a |= c;             // or in the bit value
+    ram[hl+b] = a;      // save it in RAM
+    
+    // 06f4 mviw $003f, $01 expect two bytes; jre $064c return from interrupt
+    return;
+
+    h06f9:    // note off
+    printf("went to note off\n");
+
+    a = 0xff ^ (1 << a);
+    c = a;
+    hl = 0x0040;        // note bit flags
+    a = ram[hl + b];    // byte pointed to by upper part
+    a &= c;             // mask off the bit
+    ram[hl+b] = a;      // save it in RAM    
+
+    return;
+
+}

plugin/cpuboard.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <cstdint>
+
+class Assigner {
+    public:
+    uint8_t ram[256];
+    uint16_t a = 0, b=0, c=0;
+    uint32_t bc, de, hl, ea = 0;
+
+    void noteOn();
+
+};

plugin/voice.cpp

@@ -55,7 +55,7 @@ void Voice::run(Synth &s, float *buffer, uint32_t samples) {
 
 
     float gain = 0.5*powf(2, (4*s.patchRam.vca / 127.0f) - 1.0f);
-    printf("%f %f\n",s.patchRam.vca / 127.0f, gain);
+    //printf("%f %f\n",s.patchRam.vca / 127.0f, gain);
 
     float vcaEnv = (s.patchRam.switch2 & 0x04) ? (float)ff11 : (env / 16384.0f);