1 files changed, 33 insertions, 0 deletions
diff --git a/octedit/uart.s b/octedit/uart.s
new file mode 100644
index 0000000..e79cbdc
--- /dev/null
+++ b/octedit/uart.s
@@ -0,0 +1,33 @@
+.syntax unified
+.cpu cortex-m0plus
+.thumb
+
+.equ UART0_BASE, 0x40034000
+.equ UARTDR_OFST,     0x00
+.equ UARTFR_OFST,     0x18
+
+.type uart_send, %function
+.global uart_send
+
+uart_send:
+  ldr r1, =UART0_BASE
+  movs r3, 0b1 << 5 // TX FIFO full
+1:
+  ldr r2, [r1, UARTFR_OFST]
+  tst r2, r3
+  bne 1b
+  strb r0, [r1, UARTDR_OFST]
+  bx lr
+
+.type uart_recv, %function
+.global uart_recv
+
+uart_recv:
+  ldr r1, =UART0_BASE
+  movs r3, 0b1 << 4 // RX FIFO empty
+1:
+  ldr r2, [r1, UARTFR_OFST]
+  tst r2, r3
+  bne 1b
+  ldrb r0, [r1, UARTDR_OFST]
+  bx lr