From 054d1a8c75824bb68e9f5298cde92e96d43f118e Mon Sep 17 00:00:00 2001
From: "Israel B. Sant'Anna" <ibsa14@inf.ufpr.br>
Date: Thu, 4 Jun 2015 23:24:23 -0300
Subject: [PATCH] Fixed push on rx_queue and pull on tx_queue (addresses were
not taking head and tail in account). Also rearrenged handler code since the
inclusion of a new register was needed.
Signed-off-by: Israel B. Sant'Anna <ibsa14@inf.ufpr.br>
---
cMIPS/include/handlers.s | 2 ++
cMIPS/tests/handlerUART.s | 71 ++++++++++++++++++---------------------
2 files changed, 35 insertions(+), 38 deletions(-)
diff --git a/cMIPS/include/handlers.s b/cMIPS/include/handlers.s
index c80f830..f236ac2 100644
--- a/cMIPS/include/handlers.s
+++ b/cMIPS/include/handlers.s
@@ -106,6 +106,7 @@ 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,
@@ -125,6 +126,7 @@ 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)
diff --git a/cMIPS/tests/handlerUART.s b/cMIPS/tests/handlerUART.s
index 66edd91..6239630 100644
--- a/cMIPS/tests/handlerUART.s
+++ b/cMIPS/tests/handlerUART.s
@@ -9,32 +9,30 @@ RX:
ori $a0, $a0, %lo(nrx)
lw $a1, 0($a0) # Read nrx
- addiu $a0, $zero, 16
- slt $a0, $a1, $a0 # If nrx >= 16 the queue is full
- beq $a0, $zero, END
+ addiu $a2, $zero, 16
+ slt $a2, $a1, $a2 # If nrx >= 16 the queue is full
+ beq $a2, $zero, END
- lui $a0, %hi(HW_uart_addr)
- ori $a0, $a0, %lo(HW_uart_addr)
- lw $a1, 4($a0) # Read data
-
- lui $a0, %hi(rx_queue)
- ori $a0, $a0, %lo(rx_queue)
- sw $a1, 0($a0) # Put data on RX_queue
+ addiu $a1, $a1, 1 # Increment nrx right now so we dont need to read it again
+ sw $a1, 0($a0) # Save incremented nrx
lui $a0, %hi(rx_tl)
ori $a0, $a0, %lo(rx_tl)
lw $a1, 0($a0) # Read rx_tl
nop
- addiu $a1, $a1, 1 # Increment RX_tail
- andi $a1, $a1, 15 # It's a circular queue so: (rx_tl+1)%16
- sw $a1, 0($a0) # Save new rx_tl
+ 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
+
+ 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 $a0, %hi(nrx)
- ori $a0, $a0, %lo(nrx)
- lw $a1, 0($a0) # Read nrx
- nop
- addiu $a1, $a1, 1 # Increment nrx
- sw $a1, 0($a0) # Save incremented nrx
TX:
andi $a0, $k1, UART_tx_irq # Is this transmission?
@@ -44,32 +42,29 @@ TX:
ori $a0, $a0, %lo(ntx)
lw $a1, 0($a0) # Read ntx
- addiu $a0, $zero, 16
- slt $a0, $a1, $a0 # If ntx < 16 there's something on the queue
- beq $a0, $zero, END
+ addiu $a2, $zero, 16
+ slt $a2, $a1, $a2 # If ntx < 16 there's something on the queue
+ beq $a2, $zero, END
- lui $a0, %hi(tx_queue)
- ori $a0, $a0, %lo(tx_queue)
- lw $a1, 0($a0) # Read TX_queue
-
- lui $a0, %hi(HW_uart_addr)
- ori $a0, $a0, %lo(HW_uart_addr)
- sw $a1, 0($a0) # Put data on UART
+ addiu $a1, $a1, 1 # Increment ntx
+ sw $a1, 0($a0) # Save incremented ntx
lui $a0, %hi(tx_hd)
ori $a0, $a0, %lo(tx_hd)
lw $a1, 0($a0) # Read tx_hd
nop
- addiu $a1, $a1, 1 # Increment tx_hd: we've transmitted, there's space on the queue
- andi $a1, $a1, 15 # It's a circular queue so: (tx_hd+1)%16
- sw $a1, 0($a0) # Save tx_hd
+ 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
- lui $a0, %hi(ntx)
- ori $a0, $a0, %lo(ntx)
- lw $a1, 0($a0) # Read ntx
- nop
- addiu $a1, $a1, 1 # Increment ntx
- sw $a1, 0($a0) # Save incremented ntx
+ lui $a0, %hi(tx_queue)
+ ori $a0, $a0, %lo(tx_queue)
+ add $a0, $a1, $a0 # Get queue head address (before the increment)
+ lw $a1, 0($a0) # Read TX_queue head
+
+ lui $a0, %hi(HW_uart_addr)
+ ori $a0, $a0, %lo(HW_uart_addr)
+ sw $a1, 0($a0) # Put data on UART
END:
--
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