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POWhat's going on in Apple LLVM-gcc x86 assembly?
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  1. POWhat's going on in Apple LLVM-gcc x86 assembly?
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    copied!<p>I'm interested in learning more x86/x86_64 assembly. Alas, I am on a Mac. No problem, right?</p> <pre><code>$ gcc --version i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00) Copyright (C) 2007 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. </code></pre> <p>I wrote a simple "Hello World" in C to get a base-line on what sort of code I'll have to write. I did a little x86 back in college, and have looked up numerous tutorials, but none of them look like the freakish output I'm seeing here:</p> <pre><code>.section __TEXT,__text,regular,pure_instructions .globl _main .align 4, 0x90 _main: Leh_func_begin1: pushq %rbp Ltmp0: movq %rsp, %rbp Ltmp1: subq $32, %rsp Ltmp2: movl %edi, %eax movl %eax, -4(%rbp) movq %rsi, -16(%rbp) leaq L_.str(%rip), %rax movq %rax, %rdi callq _puts movl $0, -24(%rbp) movl -24(%rbp), %eax movl %eax, -20(%rbp) movl -20(%rbp), %eax addq $32, %rsp popq %rbp ret Leh_func_end1: .section __TEXT,__cstring,cstring_literals L_.str: .asciz "Hello, World!" .section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support EH_frame0: Lsection_eh_frame: Leh_frame_common: Lset0 = Leh_frame_common_end-Leh_frame_common_begin .long Lset0 Leh_frame_common_begin: .long 0 .byte 1 .asciz "zR" .byte 1 .byte 120 .byte 16 .byte 1 .byte 16 .byte 12 .byte 7 .byte 8 .byte 144 .byte 1 .align 3 Leh_frame_common_end: .globl _main.eh _main.eh: Lset1 = Leh_frame_end1-Leh_frame_begin1 .long Lset1 Leh_frame_begin1: Lset2 = Leh_frame_begin1-Leh_frame_common .long Lset2 Ltmp3: .quad Leh_func_begin1-Ltmp3 Lset3 = Leh_func_end1-Leh_func_begin1 .quad Lset3 .byte 0 .byte 4 Lset4 = Ltmp0-Leh_func_begin1 .long Lset4 .byte 14 .byte 16 .byte 134 .byte 2 .byte 4 Lset5 = Ltmp1-Ltmp0 .long Lset5 .byte 13 .byte 6 .align 3 Leh_frame_end1: .subsections_via_symbols </code></pre> <p>Now...maybe things have changed a bit, but this isn't exactly friendly, even for assembly code. I'm having a hard time wrapping my head around this...Would someone help break down what is going on in this code and why it is all needed? </p> <p>Many, many thanks in advance.</p>
 

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