#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
    
    // 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;
    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

    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;

}