I believe that you want to load the address of your string into %rsi; your code attempts to load a quadword from that address rather than the address itself. You want: lea msg(%rip), %rsi if I’m not mistaken. I don’t have a linux box to test on, however.
Mnemonic cltq is the gas mnemonic for Intel’s cdqe as documented at: https://sourceware.org/binutils/docs/as/i386_002dMnemonics.html The mnemonics are: Convert Long To Quad (cltq): AT&T-style Convert Double to Quad Extend (cdqe): Intel Terminology: quad (aka quad-word) == 8 bytes long (AT&T) == double-word (Intel) == 4 bytes This is one of the few instructions whose GAS name is … Read more
The short answer is that you can’t. When you write assembly code it runs sequentially (or with branches) on one and only one logical (i.e. hardware) thread. If you want some of the code to execute on another logical thread (whether on the same core, on a different core on the same CPU or even … Read more
NASM actually uses its own variation of Intel syntax, different from the MASM syntax used in Intel’s official documentation. The opcode names and operand orders are the same as in Intel so the instructions look the same at first glance, but any significant program will have differences. For example with MASM the instruction used by … Read more
.file “test.c” Commands starting with . are directives to the assembler. This just says this is “file.c”, that information can be exported to the debugging information of the exe. .def ___main; .scl 2; .type 32; .endef .def directives defines a debugging symbol. scl 2 means storage class 2(external storage class) .type 32 says this sumbol … Read more
See Why Does GCC LEA EIZ?: Apparently %eiz is a pseudo-register that just evaluates to zero at all times (like r0 on MIPS). … I eventually found a mailing list post by binutils guru Ian Lance Taylor that reveals the answer. Sometimes GCC inserts NOP instructions into the code stream to ensure proper alignment and … Read more
As the DWARF spec says in section 6.4: […] The call frame is identified by an address on the stack. We refer to this address as the Canonical Frame Address or CFA. Typically, the CFA is defined to be the value of the stack pointer at the call site in the previous frame (which may … Read more
To disable these, use the gcc option -fno-asynchronous-unwind-tables -fno-dwarf2-cfi-asm may be needed also.