Trying to compile and run an app in xcode13, but dyld assertion failed:
dyld[13967]: Assertion failed: (next < &roBuffer[0x8000]), function roalloc, file
DyldProcessConfig.cpp, line 653.
dyld`__abort_with_payload:
0x100cd74d4 <+0>: mov x16, #0x209
0x100cd74d8 <+4>: svc #0x80
-> 0x100cd74dc <+8>: b.lo 0x100cd74fc ; <+40>
0x100cd74e0 <+12>: pacibsp
0x100cd74e4 <+16>: stp x29, x30, [sp, #-0x10]!
0x100cd74e8 <+20>: mov x29, sp
0x100cd74ec <+24>: bl 0x100c8ed68 ; cerror_nocancel
0x100cd74f0 <+28>: mov sp, x29
0x100cd74f4 <+32>: ldp x29, x30, [sp], #0x10
0x100cd74f8 <+36>: retab
0x100cd74fc <+40>: ret
Thread 1: signal SIGABRT
The environment is:
macOS12.0.1, xcode13.1
Anyone know something about this roalloc function and DyldProcessConfig.cpp? I google it but find nothing.
Related
I am stuck with an exercise of ARM.
The following program should calculate the result of 2((x-1)^2 + 1) but there is a mistake in the program that leads it into an infinite loop.
I think that I still don't understand completely subroutines and for this reason I am not seeing where the mistake is.
_start:
mov r0, #4
bl g
mov r7, #1
swi #0
f:
mul r1, r0, r0
add r0, r1, #1
mov pc, lr
g:
sub r0, r0, #1
bl f
add r0, r0, r0
mov pc, lr
The infinite loop starts in subroutine g: in the line of mov pc, lr and instead of returning to _start it goes to the previous line add r0, r0, r0 and then again to the last line of subroutine g:.
So I guess that the problem is the last line of subroutine g: but I can't find the way to return to _start without using mov pc, lr. I mean, this should be the command used when we have a branch with link.
Also, in this case r0 = 4, so the result of the program should be 20.
This is because you don't save lr on the stack prior to calling f, and the initial return address was therefore lost: if you only have one level of subroutine calls, using lr without saving it is fine, but if you have more then one, you need to preserve the previous value of lr.
For example, when compiling this C example using Compiler Explorer with ARM gcc 4.56.4 (Linux), and options -mthumb -O0,
void f()
{
}
void g()
{
f();
}
void start()
{
g();
}
The generated code will be:
f():
push {r7, lr}
add r7, sp, #0
mov sp, r7
pop {r7, pc}
g():
push {r7, lr}
add r7, sp, #0
bl f()
mov sp, r7
pop {r7, pc}
start():
push {r7, lr}
add r7, sp, #0
bl g()
mov sp, r7
pop {r7, pc}
If you were running this on bare metal, not under Linux, you'd need your stack pointer to be initialized a correct value.
Assuming you are running from RAM on a bare-metal system/simulator, you could setup a minimal stack of 128 bytes:
.text
.balign 8
_start:
adr r0, . + 128 // set top of stack at _start + 128
mov sp, r0
...
But it looks like you're writing a Linux executable that exits with a swi/r7=1 exit system call. So don't do that, it would make your program crash when it tries to write to the stack.
I am trying to pass r0-r5 into the function check. However only the registers r0-r3 are copied by reference. In my main function i have this code.
push {lr}
mov r0, #1
mov r1, #2
mov r2, #3
mov r3, #4
mov r4, #5
mov r5, #6
bl check
pop {lr}
bx lr
Inside my check function i have this code. This is in a separate file also not sure if that matters
m: .asciz "%d, %d ~ (%d, %d, %d)
...
push {lr}
ldr r0, =m
bl printf
pop {lr}
bx lr
The output for this is 2, 3 ~ (4, 33772, 1994545180). I am trying to learn assembly so can you please explain the answer with some googling i know i need to use the stack but, I am not sure how to use it and would like to learn how. Thanks in advance.
you could just try it and see
void check ( unsigned int, unsigned int, unsigned int, unsigned int, unsigned int );
void call_check ( void )
{
check(1,2,3,4,5);
}
arm-linux-gnueabi-gcc -c -O2 check.c -o check.o
arm-linux-gnueabi-objdump -D check.o
00000000 <call_check>:
0: e52de004 push {lr} ; (str lr, [sp, #-4]!)
4: e3a03005 mov r3, #5
8: e24dd00c sub sp, sp, #12
c: e58d3000 str r3, [sp]
10: e3a00001 mov r0, #1
14: e3a01002 mov r1, #2
18: e3a02003 mov r2, #3
1c: e3a03004 mov r3, #4
20: ebfffffe bl 0 <check>
24: e28dd00c add sp, sp, #12
28: e8bd8000 ldmfd sp!, {pc}
now of course this could be hand optimized and still work just fine. Maybe they are keeping the stack aligned on a 16 byte/4 word/64 bit boundary is the reason for the additional 12 byte modification to the stack pointer? dont know. but other than that you can see that you naturally need to save the link register since you are calling another function. r0 - r3 are obvious and then per the eabi the first thing on the stack is the 5th word worth of parameters.
Likewise for your check function you can simply let the compiler get you started. If you look at your code, r0 is coming in as your first parameter and then you trash it by changing it to the first parameter for printf. you need 6 parameters for printf to pass in. you need to move them over one the first parameter to check is the second parameter to printf, the second to check is third to printf and so on. so the code has to do that shift (two of which now are on the stack).
i´m new to assembly and using yasm, with the ebe editor.
Now after the first steps i want to check the global/extern mechanism.
Therefore i made 2 modules:
actor.asm
extern greeter
section .text
global main
main:
push rbp
call greeter wrt ..plt
pop rbp
mov rax,0
ret
greeter.asm
extern printf
section .data
msg: db "Hello world", 0
fmt: db "%s", 10, 0
section .text
global greeter
type greeter function
size greeter greeter.end -greeter
greeter:
push rbp
mov rdi,fmt
mov rsi,msg
mov rax,0
call printf
pop rbp
mov rax,0
ret
.end:
Both files are compiled and when i run the first, following error message appears:
/home/1/Öffentlich/EBE_Space/ext_glob_test/actor.o: In function
main': /home/1/Öffentlich/EBE_Space/ext_glob_test/actor.asm:6:
undefined reference togreeter'
What´s wrong?
What´s necessary to make a global function linkable?
TIA
I'm getting this error when running program:
Access violation writing location 0x0105100b
Does anyone know what's wrong with this code? It's breaking at mov [ecx],dl
.686
.model flat
extern _ExitProcess#4: PROC
public _main
.data
.code
data1 db 61H,62H,63H,64H,65H,66H,67H,68H,69H,70H,0H
data2 db 25 dup (?)
_main:
mov eax, OFFSET data1
mov ecx, OFFSET data2
mov edx, 0
mov ebp, ecx
sub ebp, eax ; licznik
mov dl, BYTE PTR [eax]
mov [ecx],dl
koniec:
push 0
call _ExitProcess#4
END
I am trying to write a simple sum function in x86 assembly - to which i am passing 3 and 8 as arguments. However, the code doesn't print the sum. Appreciate any help in spotting the errors. I'm using NASM
section .text
global _start
_sum:
push ebp
mov ebp, esp
push edi
push esi ;prologue ends
mov eax, [ebp+8]
add eax, [ebp+12]
pop esi ;epilogue begins
pop edi
mov esp, ebp
pop ebp
ret 8
_start:
push 8
push 3
call _sum
mov edx, 1
mov ecx, eax
mov ebx, 1 ;stdout
mov eax, 4 ;write
int 0x80
mov ebx, 0
mov eax, 1 ;exit
int 0x80
To me, this looks like Linux assembler. From this page, in the Examples section, subsection int 0x80, it looks like ecx expects the address of the string:
_start:
movl $4, %eax ; use the write syscall
movl $1, %ebx ; write to stdout
movl $msg, %ecx ; use string "Hello World"
movl $12, %edx ; write 12 characters
int $0x80 ; make syscall
So, you'll have to get a spare chunk of memory, convert your result to a string, probably null-terminate that string, and then call the write with the address of the string in ecx.
For an example of how to convert an integer to a string see Printing an Int (or Int to String) You'll have to store each digit in a string instead of printing it, and null-terminate it. Then you can print the string.
Sorry, I have not programmed in assembly in years, so I cannot give you a more detailed answer, but hope that this will be enough to point you in the right direction.