+ .macro senduart,rd,rx
+ strb \rd, [\rx, #UART01x_DR]
+ .endm
+
+ .macro waituart,rd,rx
+1001: ldr \rd, [\rx, #0x18] @ UARTFLG
+ tst \rd, #1 << 5 @ UARTFLGUTXFF - 1 when full
+ bne 1001b
+ .endm
+
+ .macro busyuart,rd,rx
+1001: ldr \rd, [\rx, #0x18] @ UARTFLG
+ tst \rd, #1 << 3 @ UARTFLGUBUSY - 1 when busy
+ bne 1001b
+ .endm