Fixed access to Ud on handlerUART.s and initialized Ud variables on uart.c

Signed-off-by: Israel B. Sant'Anna <ibsa14@inf.ufpr.br>

cMIPS/include/handlers.s

@@ -106,7 +106,6 @@ UARTinterr:
 	
 	sw    $a0, 12($k0)	    # save registers $a0,$a1, others?
 	sw    $a1, 16($k0)
-	sw    $a2, 18($k0)
 
 	#----------------------------------
 	# while you are developing the complete handler,
@@ -126,7 +125,6 @@ UARTinterr:
 	# sw    $a1, 8($k0)           # Signal new arrival 
 		
 UARTret:
-	lw    $a2, 18($k0)
 	lw    $a1, 16($k0)          # restore registers $a0,$a1, others?
 	lw    $a0, 12($k0)
 

cMIPS/tests/handlerUART.s

@@ -5,61 +5,62 @@ RX:
     andi  $a0, $k1, UART_rx_irq # Is this reception?
     beq   $a0, $zero, TX        #   no, test if it's transmission
 
-    lui   $a0, %hi(nrx)    
-    ori   $a0, $a0, %lo(nrx)
-    lw    $a1, 0($a0)           # Read nrx
+    lui   $a0, %hi(Ud)    
+    ori   $a0, $a0, %lo(Ud)     # $a0 <- Ud
     
-    addiu $a2, $zero, 16
-    slt   $a2, $a1, $a2         # If nrx >= 16 the queue is full
-    beq   $a2, $zero, END 
+    lw    $a1, 48($a0)          # Read nrx
+    
+
+    addiu $k1, $zero, 16
+    slt   $k1, $a1, $k1         # If nrx >= 16 the queue is full
+    beq   $k1, $zero, END 
     
     addiu $a1, $a1, 1           # Increment nrx right now so we dont need to read it again
-    sw    $a1, 0($a0)           # Save incremented nrx
+    sw    $a1, 48($a0)          # Save incremented nrx
 
-    lui   $a0, %hi(rx_tl)    
-    ori   $a0, $a0, %lo(rx_tl)
-    lw    $a1, 0($a0)           # Read rx_tl
+    lw    $a1, 20($a0)          # Read rx_tl
     nop
-    addiu $a2, $a1, 1           # Increment RX_tail
-    andi  $a2, $a2, 15          # It's a circular queue so: (rx_tl+1)%16 
-    sw    $a2, 0($a0)           # Save new rx_tl
-
-    lui   $a0, %hi(HW_uart_addr)
-    ori   $a0, $a0, %lo(HW_uart_addr)
-    lw    $a2, 4($a0)           # Read data
+    addiu $k1, $a1, 1           # Increment RX_tail
+    andi  $k1, $k1, 15          # It's a circular queue so: (rx_tl+1)%16 
+    sw    $k1, 20($a0)          # Save new rx_tl
 
-    lui   $a0, %hi(rx_queue)    
-    ori   $a0, $a0, %lo(rx_queue)
     add   $a0, $a1, $a0         # Get queue tail address (before the increment)
-    sw    $a2, 0($a0)           # Put data on RX_queue tail
+    
+    lui   $a1, %hi(HW_uart_addr)
+    ori   $a1, $a1, %lo(HW_uart_addr)
+    lw    $k1, 4($a1)           # Read data
+    nop
+    sw    $k1, 0($a0)           # Put data on RX_queue tail
+
+    #FIXME: Breaks after trying to save second character on rx_queue
+    la  $2,x_IO_BASE_ADDR 
+    sw  $k1,0($2)               # Print for debug
 
 
 TX:
     andi  $a0, $k1, UART_tx_irq # Is this transmission?
     beq   $a0, $zero, END       #   no, end handler
 
-    lui   $a0, %hi(ntx)
-    ori   $a0, $a0, %lo(ntx)
-    lw    $a1, 0($a0)           # Read ntx
+    lui   $a0, %hi(Ud)
+    ori   $a0, $a0, %lo(Ud)     # $a0 <- Ud
+
+    lw    $a1, 52($a0)          # Read ntx
 
-    addiu $a2, $zero, 16
-    slt   $a2, $a1, $a2         # If ntx < 16 there's something on the queue
-    beq   $a2, $zero, END      
+    addiu $k1, $zero, 16
+    slt   $k1, $a1, $k1         # If ntx < 16 there's something on the queue
+    beq   $k1, $zero, END      
 
     addiu $a1, $a1, 1           # Increment ntx
-    sw    $a1, 0($a0)           # Save incremented ntx
+    sw    $a1, 52($a0)          # Save incremented ntx
 
-    lui   $a0, %hi(tx_hd)
-    ori   $a0, $a0, %lo(tx_hd)
-    lw    $a1, 0($a0)           # Read tx_hd
+    lw    $a1, 40($a0)          # Read tx_hd
     nop
-    addiu $a2, $a1, 1           # Increment tx_hd: we've transmitted, there's space on the queue
-    andi  $a2, $a2, 15          # It's a circular queue so: (tx_hd+1)%16
-    sw    $a2, 0($a0)           # Save tx_hd
+    addiu $k1, $a1, 1           # Increment tx_hd: we've transmitted, there's space on the queue
+    andi  $k1, $k1, 15          # It's a circular queue so: (tx_hd+1)%16
+    sw    $k1, 40($a0)          # Save tx_hd
 
-    lui   $a0, %hi(tx_queue)
-    ori   $a0, $a0, %lo(tx_queue)
-    add   $a0, $a1, $a0         # Get queue head address (before the increment)
+    addiu $a1, $a1, 24          # tx_hd position on tx_queue
+    add   $a0, $a1, $a0         # tx_queue head address
     lw    $a1, 0($a0)           # Read TX_queue head
 
     lui   $a0, %hi(HW_uart_addr)

cMIPS/tests/uart.c

@@ -38,7 +38,7 @@ typedef struct serial {
     Tdata    d;            // TX & RX registers at address UART + 4
 } Tserial;
 
-typedef struct{
+typedef struct UARTDriver{
     char rx_q[16];         // reception queue
     int rx_hd;             // reception queue head index
     int rx_tl;             // reception queue tail index
@@ -58,6 +58,8 @@ void ioctl(int);           // write lsb in control register
 char getc(void);           // returns char in queue, decrements nrx
 int Putc(char);            // inserts char in queue, decrements ntx
 
+void initUd();
+
 extern UARTDriver Ud;
 
 int main(){
@@ -65,6 +67,7 @@ int main(){
     volatile int state;    // tell GCC not to optimize away code
     volatile Tserial *uart;
     volatile Tstatus status;
+    volatile char c;
     Tcontrol ctrl;
 
     uart = (void *)IO_UART_ADDR; // bottom of UART address range
@@ -75,27 +78,50 @@ int main(){
     ctrl.speed = 1;        // operate at 1/2 of the highest data rate
     uart->cs.ctl = ctrl;
 
-    char c;
+    initUd();
+
     uart->d.tx = 'a';
-    while((c=getc())!='\0'){
-        to_stdout(c);
-        Putc(c);
-    }
+
+    //print(lol);
+    /*while(c!='\n'){
+        /*to_stdout('X');
+        to_stdout('\n');
+        //print(lol);
+        c=getc();
+    }*/
+
+    while(1)
+        c=getc();
 
     return 0;
 }
 
+void initUd(){
+    Ud.rx_hd = 0;
+    Ud.rx_tl = 0;
+    Ud.tx_hd = 0;
+    Ud.tx_tl = 0;
+    Ud.nrx = 0;
+    Ud.ntx = 16;
+}
+
 char getc(){
     char c;
     if(Ud.nrx > 0){
+        // print(1);
+        // print(Ud.nrx);
         c = Ud.rx_q[Ud.rx_hd];
         Ud.rx_hd = (Ud.rx_hd+1)%16;
         disableInterr();
         Ud.nrx--;
         enableInterr();
     }else{
+        //print(2);
         c = EOF;
     }
+    // print((int)c);
+    // to_stdout(c);
+    // to_stdout('\n');
     return c;
 }