Talvez rx esteja pronto

Signed-off-by: Jedian <jmb15@c3sl.ufpr.br>

cMIPS/tests/handlerUARTjedi2.s

@@ -22,6 +22,16 @@
     sw    $6, 10*4($k0)
     sw    $7, 11*4($k0)
     
+    # check if queue is full, maybe increment
+    lui   $5, %hi(nrx)
+    ori   $5, $5, %lo(nrx)
+    lw    $7, 0($5)
+    slti  $6, $7, 16
+    beq   $6, zero, overrun
+    nop
+    addiu $7, $7, 1
+    sw    $7, 0($5)
+
     # enqueue
     lui   $5, %hi(rx_tl)        # get rx tail address
     ori   $5, $5, %lo(rx_tl)    
@@ -42,9 +52,14 @@
     sb    $7, 0($6)             # and store it!
 
     #### process rx_tl -- update tail
-    #lw    $7, 0($5)
+    #lw   $7, 0($5)
     #nop
 
+overrun:
+
+    # do something if queue is full
+    #... (doing absolutely nothing besides stacking and unstacking regs)
+
     # loading back used registers
     lw    $5, 9*4($k0)
     lw    $6, 10*4($k0)