forked from PAWPAW-Mirror/lib_xua
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Dave Lacey
218
module_usb_midi/src/midiinparse.xc
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218
module_usb_midi/src/midiinparse.xc
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/**
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* @file midiinparse.xc
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* @brief Generates USB MIDI events from MIDI events
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* @author Russell Gallop, XMOS Semiconductor
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* @version 0.1
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*/
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#include <print.h>
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//#include <assert.h>
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#include "midiinparse.h"
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/**
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* @brief Report state of the MIDI in parser (should be removed by deadcode elimination)
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*
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*/
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void dump_midi_in_parse_state(struct midi_in_parse_state &s) {
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printstr("expect_msg_len: 0x"); printhexln(s.expect_msg_len);
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printstr("msg_type: 0x"); printhexln(s.msg_type);
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printstr("receivebuffer: 0x"); printhex(s.receivebuffer[0]);
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printstr(", 0x"); printhex(s.receivebuffer[1]);
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printstr(", 0x"); printhexln(s.receivebuffer[2]);
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printstr("received: 0x"); printhexln(s.received);
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printstr("codeIndexNumber: 0x"); printhexln(s.codeIndexNumber);
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}
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/**
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* @brief Reset state of MIDI parser
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*
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*/
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void reset_midi_state(struct midi_in_parse_state &mips) {
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mips.expect_msg_len = 0;
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mips.msg_type = 0;
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mips.receivebuffer[0] = 0;
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mips.receivebuffer[1] = 0;
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mips.receivebuffer[2] = 0;
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mips.received = 0;
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mips.codeIndexNumber = 0;
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}
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/**
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* @brief Construct USB MIDI event
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*
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*/
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unsigned makeEvent(unsigned cable_number, unsigned codeIndexNumber, unsigned midi0, unsigned midi1, unsigned midi2) {
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unsigned event = (cable_number << 28);
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event |= (codeIndexNumber << 24);
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event |= (midi0 << 16);
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event |= (midi1 << 8);
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event |= (midi2 << 0);
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return event;
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}
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/**
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* @ brief MIDI input parser
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*
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*/
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{unsigned int , unsigned int} midi_in_parse(struct midi_in_parse_state &state, unsigned cable_number, unsigned char b) {
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unsigned valid = 0;
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unsigned data = 0xBADDF00D; // should never be returned along with valid = 1
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unsigned highNibble = (b & 0xF0) >> 4;
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unsigned lowNibble = (b & 0xF);
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/*
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assert(!(state.expect_msg_len && state.msg_type == INSYSEX_MSG));
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assert((state.received >= 1) || (state.receivebuffer[0] == 0));
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assert((state.received >= 2) || (state.receivebuffer[1] == 0));
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assert((state.received == 3) || (state.receivebuffer[2] == 0));
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assert(state.received < 3);
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*/
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if (b & 0x80) { // Is status byte
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if (highNibble == 0xF) { // System message
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if (lowNibble & 0x8) { // System real time
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// System Real-Time Messages (can interleave system exclusive and between header and data (page 30 of complete MIDI spec))
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//case 0x8: // Timing tick
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//case 0x9: // Reserved
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//case 0xA: // Start song
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//case 0xB: // Continue song
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//case 0xC: // Stop song
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//case 0xD: // Reserved
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//case 0xE: // Active sensing
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//case 0xF: // System reset
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// Have complete event, send out
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valid = 1;
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data = makeEvent(cable_number, highNibble, b, 0, 0);
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} else {
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if (b == 0xF7) { // End of SysEx
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state.receivebuffer[state.received] = b;
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state.received++;
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// Compose sysex bytes that we've got and send them out.
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// This will depend how many we have.
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state.codeIndexNumber = state.received + 0x4;
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valid = 1;
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data = makeEvent(cable_number, state.codeIndexNumber,
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state.receivebuffer[0], state.receivebuffer[1], state.receivebuffer[2]);
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reset_midi_state(state);
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} else {
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reset_midi_state(state);
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state.receivebuffer[state.received] = b;
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state.received++;
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switch (lowNibble)
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{
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case 0x2: // Song Position Pointer (3 byte system common)
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{
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state.msg_type = INSYSCOMMON_MSG;
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state.expect_msg_len = 3;
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state.codeIndexNumber = 3;
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break;
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}
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case 0x1: // MIDI Time Code (2 byte system common)
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case 0x3: // Song Select (2 byte system common)
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{
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state.msg_type = INSYSCOMMON_MSG;
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state.expect_msg_len = 2;
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state.codeIndexNumber = 2;
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break;
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}
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case 0x6: // Tune request (1 byte system common)
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state.codeIndexNumber = 5;
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valid = 1;
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data = makeEvent(cable_number, state.codeIndexNumber,
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state.receivebuffer[0], state.receivebuffer[1], state.receivebuffer[2]);
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break;
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case 0x0: // Sysex start byte, never send based on just this
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state.msg_type = INSYSEX_MSG;
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break;
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default:
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// Could happen with unrecognised headers, e.g. 0xF4, 0xF5
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// Just pass on
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valid = 1;
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data = makeEvent(cable_number, 0x0f, b, 0, 0);
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reset_midi_state(state);
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break;
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}
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}
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}
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} else { // Channel message
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reset_midi_state(state);
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state.receivebuffer[state.received] = b;
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state.received++;
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// code index number is always the high nibble for channel messages
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state.codeIndexNumber = highNibble;
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switch (highNibble)
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{
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case 0x8: // Note-off
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case 0x9: // Note-on
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case 0xA: // Poly-KeyPress
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case 0xB: // Control Change
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case 0xE: // PitchBend Change
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{
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state.msg_type = INCHANNEL_MSG;
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state.expect_msg_len = 3;
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break;
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}
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case 0xC: // Program Change
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case 0xD: // Channel Pressure
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{
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state.msg_type = INCHANNEL_MSG;
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state.expect_msg_len = 2;
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break;
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}
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}
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}
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} else { // data byte
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state.receivebuffer[state.received] = b;
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state.received++;
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switch (state.msg_type) {
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case INCHANNEL_MSG:
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case INSYSCOMMON_MSG:
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{
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if (state.received == state.expect_msg_len) {
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valid = 1;
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data = makeEvent(cable_number, state.codeIndexNumber,
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state.receivebuffer[0], state.receivebuffer[1], state.receivebuffer[2]);
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if (state.msg_type == INSYSCOMMON_MSG) {
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// No running status on system common messages
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reset_midi_state(state);
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} else {
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// Keep the first byte on channel messages, already received 1 byte
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state.received = 1;
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state.receivebuffer[1] = 0;
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state.receivebuffer[2] = 0;
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}
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}
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break;
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}
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case INSYSEX_MSG:
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{
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if ((state.received == 3)) {
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// Output if have 3 using the SysEx starts or continues
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state.codeIndexNumber = 0x4;
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valid = 1;
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data = makeEvent(cable_number, state.codeIndexNumber,
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state.receivebuffer[0], state.receivebuffer[1], state.receivebuffer[2]);
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// reset buffer but not msg_type
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state.received = 0;
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state.receivebuffer[0] = 0;
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state.receivebuffer[1] = 0;
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state.receivebuffer[2] = 0;
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}
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break;
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}
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default:
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{
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// Else data byte with no status so just send as single byte without parsing.
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valid = 1;
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data = makeEvent(cable_number, 0x0f, b, 0, 0);
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reset_midi_state(state);
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break;
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}
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}
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}
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return {valid, data};
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}
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