FreeCalypso > hg > freecalypso-tools
view target-utils/libbase/serio.S @ 479:f2a040324509
Makefile hierarchy: CFLAGS override-ability actually works now
The original version was broken in that CFLAGS=${CFLAGS} passing was
done without quotes, which breaks as soon as there is a space in the
user-set CFLAGS. Changing it to CFLAGS="${CFLAGS}" makes it work
as originally intended.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Thu, 14 Feb 2019 04:59:23 +0000 |
parents | da6df2c626cf |
children |
line wrap: on
line source
#include "ns16550.h" @ this module implements the elementary serial I/O operations .comm uart_base,4,4 .text .code 32 .global serial_out serial_out: ldr r1, =uart_base ldr r2, [r1] 1: ldrb r3, [r2, #0x11] @ Calypso UART non-std register SSR tst r3, #0x01 @ Tx FIFO full flag bne 1b strb r0, [r2, #NS16550_THR] bx lr .global serial_in_poll serial_in_poll: ldr r1, =uart_base ldr r2, [r1] ldrb r3, [r2, #NS16550_LSR] tst r3, #NS16550_LSR_DR ldrneb r0, [r2, #NS16550_RBR] mvneq r0, #0 bx lr .global serial_flush serial_flush: ldr r1, =uart_base ldr r2, [r1] 1: ldrb r3, [r2, #NS16550_LSR] tst r3, #NS16550_LSR_TEMP beq 1b bx lr