1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
.section ".text"
.globl uart_char
uart_char:
mov r2, #0x1000
movt r2, #0x3f20
1:
ldr r3, [r2, #24]
tst r3, #0b100000
bne 1b
str r0, [r2]
bx lr
.globl uart_string
uart_string:
push {r4, lr}
mov r4, r0
ldrb r0, [r0]
cmp r0, #0
popeq {r4, pc}
1:
bl uart_char
ldrb r0, [r4, #1]!
cmp r0, #0
bne 1b
pop {r4, pc}
.globl uart_hex
uart_hex:
push {r4, lr}
mov r2, #0x1000
movt r2, #0x3f20
1:
ldr r3, [r2, #24]
tst r3, #0b100000
bne 1b
mov r3, #7
2:
mov r1, r0
asr r1, r3
asr r1, r3
asr r1, r3
asr r1, r3
and r1, #0xf
add r1, #0x30
cmp r1, #0x3A
blt 3f
add r1, #7
3:
str r1, [r2]
subs r3, #1
bge 2b // Jump back to wait for availablilty
pop {r4, pc}
|
