Merge commit '1ec2c28deda76ce392849805fedd435cea103624' into feature/midi_docs

lib_xua/src/midi/midioutparse.h

@@ -1,8 +1,14 @@
-// Copyright 2011-2021 XMOS LIMITED.
+// Copyright 2011-2024 XMOS LIMITED.
 // This Software is subject to the terms of the XMOS Public Licence: Version 1.
 #ifndef MIDIOUTPARSE_XH
 #define MIDIOUTPARSE_XH
 
+// If for any reason we pop a message when not needed (should never happen) this will cause midiparse out to send a size of 0 (drops packet)
+#define MIDI_OUT_NULL_MESSAGE   0x00000000
+
+#ifdef __XC__
+// Takes a MIDI packet and decomoses it into up to 3 data bytes followed by a byte count.
 {unsigned, unsigned, unsigned, unsigned} midi_out_parse(unsigned event);
+#endif
 
 #endif

lib_xua/src/midi/queue.h

@@ -3,7 +3,9 @@
 #ifndef QUEUE_H_
 #define QUEUE_H_
 
-#define assert(x) asm("ecallf %0"::"r"(x));
+#include "midioutparse.h"
+#include "xassert.h"
+
 
 typedef struct queue_t {
     /// Read index.
@@ -21,7 +23,7 @@ inline int is_power_of_2(unsigned x) {
 }
 
 inline void queue_init(queue_t &q, unsigned size) {
-    assert(is_power_of_2(size));
+    xassert(is_power_of_2(size) && "MIDI FIFO size must be a power of 2"); // Keep this enabled as will be discovered duirng dev time
     q.rdptr = 0;
     q.wrptr = 0;
     q.size = size;
@@ -38,25 +40,26 @@ inline int queue_is_full(const queue_t &q) {
 
 inline void queue_push_word(queue_t &q, unsigned array[], unsigned data)
 {
-    assert(!queue_is_full(q));
+
+    if(queue_is_full(q)) {
+        xassert(0 && "Unexpected push to MIDI queue when full");
+        // Silently drop message if asserts not enabled
+        return;
+    }
+
     array[q.wrptr++ & q.mask] = data;
 }
 
 inline unsigned queue_pop_word(queue_t &q, unsigned array[]) {
-    assert(!queue_is_empty(q));
+    if(queue_is_empty(q)){
+        xassert(0 && "Unexpected pop from MIDI queue when empty");
+        // Return NULL messaqe if asserts not enabled
+        return MIDI_OUT_NULL_MESSAGE; 
+    }
+
     return array[q.rdptr++ & q.mask];
 }
 
-inline void queue_push_byte(queue_t &q, unsigned char array[], unsigned data)
-{
-    assert(!queue_is_full(q));
-    array[q.wrptr++ & q.mask] = data;
-}
-
-inline unsigned queue_pop_byte(queue_t &q, unsigned char array[]) {
-    assert(!queue_is_empty(q));
-    return array[q.rdptr++ & q.mask];
-}
 
 inline unsigned queue_items(const queue_t &q) {
     return q.wrptr - q.rdptr;

lib_xua/src/midi/queue.xc

@@ -1,4 +1,4 @@
-// Copyright 2013-2021 XMOS LIMITED.
+// Copyright 2013-2024 XMOS LIMITED.
 // This Software is subject to the terms of the XMOS Public Licence: Version 1.
 #include "queue.h"
 
@@ -9,7 +9,5 @@ extern inline int queue_is_empty(const queue_t &q);
 extern inline int queue_is_full(const queue_t &q);
 extern inline void queue_push_word(queue_t &q, unsigned array[], unsigned data);
 extern inline unsigned queue_pop_word(queue_t &q, unsigned array[]);
-extern inline void queue_push_byte(queue_t &q, unsigned char array[], unsigned data);
-extern inline unsigned queue_pop_byte(queue_t &q, unsigned char array[]);
 extern inline unsigned queue_space(const queue_t &q);
 extern inline unsigned queue_items(const queue_t &q);

lib_xua/src/midi/usb_midi.xc

@@ -1,4 +1,4 @@
-// Copyright 2011-2022 XMOS LIMITED.
+// Copyright 2011-2024 XMOS LIMITED.
 // This Software is subject to the terms of the XMOS Public Licence: Version 1.
 #include <xs1.h>
 #include <xclib.h>
@@ -13,7 +13,7 @@
 #include "iap_user.h"
 #include "coprocessor_user.h"
 #endif
-//#define MIDI_LOOPBACK 1
+
 int icount = 0;
 static unsigned makeSymbol(unsigned data)
 {
@@ -89,9 +89,9 @@ void usb_midi(
 
     struct midi_in_parse_state mips;
 
-    // the symbol fifo (to go out of uart)
+    // the symbol fifo (to go out of uart).
     queue_t symbol_fifo;
-    unsigned symbol_fifo_arr[USB_MIDI_DEVICE_OUT_FIFO_SIZE]; // Used for 32bit USB MIDI events
+    unsigned symbol_fifo_arr[USB_MIDI_DEVICE_OUT_FIFO_SIZE]; // Used for outgoing UART symbols (which include the start and stop bit)
 
     unsigned rxPT, txPT;
     int midi_from_host_overflow = 0;
@@ -264,7 +264,7 @@ void usb_midi(
             }
             break;
 #endif
-
+        // Received as packet from USB
         case !authenticating => midi_get_ack_or_data(c_midi, is_ack, datum):
 
             if (is_ack)
@@ -281,6 +281,7 @@ void usb_midi(
                 }
             }
             else
+            // A midi packet from the host
             {
                 unsigned midi[3];
                 unsigned size;
@@ -327,7 +328,7 @@ void usb_midi(
                     midi_from_host_overflow = 1;
                 }
                 // Drop through to the isTX guarded case
-                if (!isTX)
+                if (!isTX && size > 0) // do not start tx'ing if this packet has no size
                 {
                     t :> txT; // Should be enough to trigger the other case
                     isTX = 1;