Please forgive me if I'm emailing the wrong list. I was referred by the gcc documentation. Hello, I'm a student having a bit of trouble compiling with gcc. I attempted to compile a few programs with the -S option, and got pretty strange results... is this a feature, or something I somehow should understand? I copied below the files outputed and what I expected. Some instructions are of extreme strangeness, such as mov $0, %eax subl %eax, %esp What is the point of doing this? For one thing, stdcall doesn't require %eax to be zeroed(or does it?). Whatmore, it's totally weird and useless to subtract zero from any value, especially considering no conditional jump follows... So what am I missing? thank you, Kazuo kazuo@xxxxxxxxxxxxxxxx ######################################### # file 1: the code the way i expected it ######################################### .file "blah.c" .section .rodata .LC0: .string "hello world\n" .text .globl somefunc .type somefunc,@function somefunc: pushl %ebp movl %esp, %ebp pushl $.LC0 call printf leave ret .Lfe1: .size somefunc,.Lfe1-somefunc .globl main .type main,@function main: pushl %ebp movl %esp, %ebp call somefunc movl $0, %eax leave ret .Lfe2: .size main,.Lfe2-main .ident "kaz 0.0001" ################################# # file 2: the code by gcc 3.2.3 ################################# .file "blah.c" .section .rodata .LC0: .string "hello world\n" .text .globl somefunc .type somefunc,@function somefunc: pushl %ebp movl %esp, %ebp subl $8, %esp subl $12, %esp pushl $.LC0 call printf addl $16, %esp leave ret .Lfe1: .size somefunc,.Lfe1-somefunc .globl main .type main,@function main: pushl %ebp movl %esp, %ebp subl $8, %esp andl $-16, %esp movl $0, %eax subl %eax, %esp call somefunc movl $0, %eax leave ret .Lfe2: .size main,.Lfe2-main .ident "GCC: (GNU) 3.2.3"
