All Questions
Tagged with relocation assembly
47 questions
2
votes
1
answer
48
views
Use symbol address to generate page table entry
I am working on writing a static paging setup for a custom bare-metal ARM system. ARMv7a uses two-level paging, where entries in a top-level page table can point to a second-level table. I have a top-...
2
votes
0
answers
87
views
relative address instead of absolute address in the relocation table
In the context of compiler optimization and linker behavior, I'm trying to understand the implications of using relative addresses instead of absolute addresses in the relocation table during the ...
- 394
5
votes
1
answer
268
views
Calculation of relative offset in small code model
I am trying to understand the RIP relative offset used in small-code model. Perhaps the only approachable resource on the internet on this topic is: https://eli.thegreenplace.net/2012/01/03/...
- 705
0
votes
1
answer
1k
views
Relocation error happening locally but not in godbolt
Consider this program on godbolt:
#include <cassert>
#include <cstdint>
int64_t const x[] = { 42, 2, 3, 4 };
int64_t f() {
int64_t i;
asm volatile (
"xor %[i], %[i]\n\t"...
- 20.4k
0
votes
0
answers
314
views
`auipc` and branch relaxation on RISC-V
For many tasks on RISC-V, a sequence ofauipc and an instruction with a short offset is used for PC-relative addressing (including jumps). This needs a temporary register. The GNU linker is capable of ...
- 1,994
4
votes
1
answer
350
views
Why can't I assemble absolute addresses in the .text section on ARM64 MacOS?
I'm writing in assembly using clang 13.1.6 with MacOS Monterey 12.5 on an ARM64 M1 Pro laptop.
If I try to use .dword/.xword in the .text section with the address of a label as its value, my program ...
- 57.2k
3
votes
1
answer
2k
views
Why is a RIP-relative LEA instruction producing a PIC-incompatible R_X86_64_32S relocation?
I'm going through the x86-64 tutorial on exercism.org. I'm using NASM on Linux, producing an ELF binary. There is just a bit of C code that invokes my assembly code in a test harness. Their build ...
- 6,332
0
votes
1
answer
590
views
Cannot represent relocation type BFD_RELOC_X86_64_GOTPC64
I get this error whenever I try to use -mcmodel=large does anyone know why this is?
I am on Windows 10 using gcc 10.2.0
- 149
0
votes
1
answer
506
views
How does a linker relocate branch instructions in MIPS?
Background
I'm working on a 2015 CS61C (Berkeley) course project on writing a linker to link object files generated from the following subset of the MIPS instruction set.
Add Unsigned: addu $rd, $rs, $...
- 407
0
votes
0
answers
198
views
Question about relocation entries in assembly code
I write 2 C programs : main.c and sum.c.
Here is main.c :
int array[2] = {1, 2};
int main() {
int val = sum(array, 2);
return val;
}
Here is sum.c :
int sum(int* a, int n) {
int i, s = 0;
...
- 109
0
votes
0
answers
21
views
In object file produced by assembler what is the address used in places where linker is supposed to link the correct address? [duplicate]
So an assembler converts the assembly language code into an object file and a linker would then produce an executable file which we can use to execute the program. The job of linker is to link the ...
- 125
2
votes
1
answer
608
views
Why function that refers to a global function in the same section can only be solved at link time while local functions will be solve at compile time?
I have this assembly file prog.S :
.text
#------------------------------main----------------------------------
.globl main
.type main,@function
main:
pushl %ebp
movl %esp, %ebp
call ...
- 23
0
votes
1
answer
369
views
What are code Relocations ins AArch64, are they the same as the relocation for dynamic linking?
Reading the manual for GNU ASM I came across the syntax #:abs_g0_nc: and :pg_hi21:. This code loads different bit ranges of a value into a register, yet it is called relocation. I know what relocation ...
- 13
2
votes
0
answers
170
views
How does an operating system change a process's virtual base address?
To clarify, my specific confusion is centered around the fact that all instructions in a PE executable are written assuming the base image address is = 00400000. However, when debugging an executable, ...
- 163
0
votes
1
answer
287
views
MS-DOS executable's [mov] instruction dynamic relocating at entry point
I've disassembled a MS-DOS Executable(16-bits) in IDA, the first instruction at entry point is
mov ax, 0x1000 ; B8 00 10
However, when dumping raw hex, the corresponding field is
mov ax, 0x0000 ; ...
- 113