FreeCalypso > hg > freecalypso-tools
annotate target-utils/libbase/serio.S @ 407:19e5a3e2f9c0
fcup-settime: moved time() retrieval a little closer to the output
A fundamental problem with all simple time transfer tools is that there is
always some delay between the time retrieval on the source system and that
transmitted time being set on the destination, and the resulting time
on the destination system is off by that delay amount. This delay cannot
be fully eliminated when working in a simple environment like ours,
but we should make our best effort to minimize it. In the present case,
moving the atinterf_init() call before the time() retrieval should make
a teensy-tiny improvement.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Sat, 11 Aug 2018 21:52:17 +0000 |
parents | da6df2c626cf |
children |
rev | line source |
---|---|
0
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
1 #include "ns16550.h" |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
2 |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
3 @ this module implements the elementary serial I/O operations |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
4 |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
5 .comm uart_base,4,4 |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
6 |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
7 .text |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
8 .code 32 |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
9 .global serial_out |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
10 serial_out: |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
11 ldr r1, =uart_base |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
12 ldr r2, [r1] |
401
da6df2c626cf
target-utils: wait for FIFO not full in serial_out() instead of FIFO empty
Mychaela Falconia <falcon@freecalypso.org>
parents:
0
diff
changeset
|
13 1: ldrb r3, [r2, #0x11] @ Calypso UART non-std register SSR |
da6df2c626cf
target-utils: wait for FIFO not full in serial_out() instead of FIFO empty
Mychaela Falconia <falcon@freecalypso.org>
parents:
0
diff
changeset
|
14 tst r3, #0x01 @ Tx FIFO full flag |
da6df2c626cf
target-utils: wait for FIFO not full in serial_out() instead of FIFO empty
Mychaela Falconia <falcon@freecalypso.org>
parents:
0
diff
changeset
|
15 bne 1b |
0
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
16 strb r0, [r2, #NS16550_THR] |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
17 bx lr |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
18 |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
19 .global serial_in_poll |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
20 serial_in_poll: |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
21 ldr r1, =uart_base |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
22 ldr r2, [r1] |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
23 ldrb r3, [r2, #NS16550_LSR] |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
24 tst r3, #NS16550_LSR_DR |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
25 ldrneb r0, [r2, #NS16550_RBR] |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
26 mvneq r0, #0 |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
27 bx lr |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
28 |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
29 .global serial_flush |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
30 serial_flush: |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
31 ldr r1, =uart_base |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
32 ldr r2, [r1] |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
33 1: ldrb r3, [r2, #NS16550_LSR] |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
34 tst r3, #NS16550_LSR_TEMP |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
35 beq 1b |
e7502631a0f9
initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
36 bx lr |