Код: Выделить всё
.text
.include "gpioLedMacros.s"
.global _start
.align 4
_start:
mmapdevmem
adds x9, xzr, x0
nanosleep
gpiodirectionout pin17
loop:
gpioturnon pin17
nanosleep
gpioturnoff pin17
nanosleep
b loop
.data
pin17:
.word 4 /* pin offset value in select */
.word 21
.word 17
.align 4
pin22:
.word 8 /* pin offset value in select */
.word 6
.word 22
.align 4
//Execution File
Код: Выделить всё
.include "fileMacros.s"
.equ prot_read, 1
.equ prot_write, 2
.equ map_shared, 1
.equ pageLength, 4096
.equ setregoffset, 28
.equ clrregoffset, 40
/* mmap creates a virtual page of memory in a specified, or non specified
directory, with a varible page size/length for the page created, then returns
a virtual address for the virtual page created */
.macro mmapdevmem
openat devmem, readwrite+execute, stdin
b1:
adds x4, xzr, x0 /* mov devmem file descriptor into x4 */
/* Error handling code */
bpl 1f
mov x1, #1
ldr x2, =devmemerrmessage
ldr w2, [x2]
mov x8, #0x40
svc 0
mov x0, #2
mov x8, #0x5d
svc 0
1:
ldr x5, =gpioBaseAddress/* Load the base gpio address into x5 */
ldr x5, [x5] /* Load the value from the base gpio address */
mov x0, #0 /* move 0 into x0 for stdin */
mov x1, #pageLength /* move 4096 which is the page length into x1 */
mov x2, #3 /* move protect read, and protect write permissions into x2 */
mov x3, #map_shared /* move the map shared value into x3, which is 1 */
mov x8, #0xde /* load the value for the mmap syscall into x8 */
svc 0 /* call mmap */
adds x9, xzr, x0 /* Obtain file descriptor returned from mmap */
bpl 2f
mov x1, #1
write x1, errmessage, len
2:
/* x0 = 0
x1 = 4096
x2 = 3
x3 = 1
x4 = fd for /dev/mem
x5 = value in baseGpioAddress
x8 = 0xde / mmap
x9 = mmap returned file descriptor */
.endm
.macro nanosleep
ldr x0, =timeamount
ldr x1, =timeamount
mov x8, #0x65
svc 0
.endm
.macro gpiodirectionout pin
ldr x2, =\pin /* Load the pin number into x2 */
ldr w2, [x2] /* Load the value of that pin number into x2 */
ldr w1, [x9, x2]/* Load into x1 the value of the file descriptor of mmap offset by the value of the pin that you're trying to set */
ldr x3, =\pin /* Load the pin number into x3 */
add x3, x3, #4 /* add the amount to shift to the pin number */
ldr x3, [x3] /* Load the value of the shift amount of the pin into x3 */
mov x0, #0b111 /* Load 3 1 bits (which is the clear value) into x0 */
lsl x0, x0, x3 /* Shift the 3 1 bits by the pin shift amount */
bic x1, x1, x0 /* Use the 3 bits to clear the mmap offset file descriptor value */
mov x0, #1 /* Move 1 into x0 for the out value */
lsl x0, x0, x3 /* Shift the out bit by the pin shift amount */
orr x1, x1, x0 /* orr the out bit with the mmap file descriptor pin offset value */
str w1, [x9, x2]/* store the out bit into the mmap file descriptor pin offset */
.endm
.macro gpioturnon pin
mov x2, x9
add x2, x2, #setregoffset
mov x0, #1
ldr x3, =\pin
add x3, x3, #8
ldr x3, [x3]
lsl x0, x0, x3
str w0, [x2]
.endm
.macro gpioturnoff pin
mov x2, x9
add x2, x2, #clrregoffset
mov x0, #1
ldr x3, =\pin
add x3, x3, #8
ldr w3, [x3]
lsl x0, x0, x3
str w0, [x2]
.endm
.data
devmem:
.asciz "/dev/mem"
timeamount:
.dword 0
timeremaining:
.dword 10000000
gpioBaseAddress:
.dword 0xfe200000
errmessage:
.asciz "Couldn't obtain file descriptor for /dev/mem\n"
len = .-errmessage
devmemerrmessage:
.asciz "Couldn't obtain devmem file descriptor\n"
len2 = .-devmemerrmessage
//gpio macro file
Код: Выделить всё
equ dfd, -100
.equ stdin, 0
.equ readwrite, 0666
.equ execute, 0200
.macro openat filename, flags, permissions
ldr x0, =dfd
ldr x1, =\filename
mov x2, #\flags
mov x3, #\permissions
mov x8, #0x38
svc 0
.endm
.macro fchmod fd, permissions
mov x0, \fd
ldr x1, =\permissions
mov x8, #0x34
svc 0
.endm
.macro read fd, fillblock, length
mov x0, \fd
ldr x1, =\fillblock
mov x2, #\length
mov x8, #0x3f
svc 0
.endm
.macro write fd, string, length
mov x0, \fd
ldr x1, =\string
mov x2, \length
mov x8, #0x40
svc 0
.endm
.macro fsync fd
mov x0, \fd
mov x8, #0x52
svc 0
.endm
.macro close fd
mov x0, \fd
mov x8, #0x39
svc 0
.endm
// File macro file
Подробнее здесь: https://stackoverflow.com/questions/787 ... mem-in-arm
