Hi all,I'm now busy implementing early_kprintf aimed to print strings into screen.For test I write a simple function as follow:
int early_kprintf(char* fmt,char* fmt2,...)
{
return 0;
}
After compiling by x86_64-pc-linux-gnu-gcc(with version 3.4.0), I tried to link all .o files.But "relocationg truncated to fit: .text 0x6fe+.text" error again happened.I ran objdump to dump the very .o file,I found it strange:
00000000000006b0 <early_kprintf>:
6b0: 55 push %rbp
6b1: 48 89 e5 mov %rsp,%rbp
6b4: 48 81 ec d0 00 00 00 sub $0xd0,%rsp
6bb: 48 89 bd 48 ff ff ff mov %rdi,0xffffffffffffff48(%rbp)
6c2: 48 89 95 60 ff ff ff mov %rdx,0xffffffffffffff60(%rbp)
6c9: 48 89 8d 68 ff ff ff mov %rcx,0xffffffffffffff68(%rbp)
6d0: 4c 89 85 70 ff ff ff mov %r8,0xffffffffffffff70(%rbp)
6d7: 4c 89 8d 78 ff ff ff mov %r9,0xffffffffffffff78(%rbp)
6de: 0f b6 c0 movzbl %al,%eax
6e1: 48 89 85 38 ff ff ff mov %rax,0xffffffffffffff38(%rbp)
6e8: 48 8b 95 38 ff ff ff mov 0xffffffffffffff38(%rbp),%rdx
6ef: 48 8d 04 95 00 00 00 lea 0x0(,%rdx,4),%rax
6f6: 00
6f7: 48 c7 85 38 ff ff ff movq $0x0,0xffffffffffffff38(%rbp)
6fe: 00 00 00 00
702: 48 29 85 38 ff ff ff sub %rax,0xffffffffffffff38(%rbp)
709: 48 8d 45 ff lea 0xffffffffffffffff(%rbp),%rax
70d: 48 8b 95 38 ff ff ff mov 0xffffffffffffff38(%rbp),%rdx
714: ff e2 jmpq *%edx
716: 0f 29 78 f1 movaps %xmm7,0xfffffffffffffff1(%rax)
71a: 0f 29 70 e1 movaps %xmm6,0xffffffffffffffe1(%rax)
71e: 0f 29 68 d1 movaps %xmm5,0xffffffffffffffd1(%rax)
722: 0f 29 60 c1 movaps %xmm4,0xffffffffffffffc1(%rax)
726: 0f 29 58 b1 movaps %xmm3,0xffffffffffffffb1(%rax)
72a: 0f 29 50 a1 movaps %xmm2,0xffffffffffffffa1(%rax)
72e: 0f 29 48 91 movaps %xmm1,0xffffffffffffff91(%rax)
732: 0f 29 40 81 movaps %xmm0,0xffffffffffffff81(%rax)
736: 48 89 b5 40 ff ff ff mov %rsi,0xffffffffffffff40(%rbp)
73d: b8 00 00 00 00 mov $0x0,%eax
742: c9 leaveq
743: c3 retq
I think it strange that why GCC refers to xmm registers.And I found no resolutions from GCC doc-book.Any help is appreciated.
