| /* |
| * Zero a page. |
| * rdi page |
| */ |
| .globl clear_page |
| .p2align 4 |
| clear_page: |
| xorl %eax,%eax |
| movl $4096/64,%ecx |
| .p2align 4 |
| .Lloop: |
| decl %ecx |
| #define PUT(x) movq %rax,x*8(%rdi) |
| movq %rax,(%rdi) |
| PUT(1) |
| PUT(2) |
| PUT(3) |
| PUT(4) |
| PUT(5) |
| PUT(6) |
| PUT(7) |
| leaq 64(%rdi),%rdi |
| jnz .Lloop |
| nop |
| ret |
| clear_page_end: |
| |
| /* Some CPUs run faster using the string instructions. |
| It is also a lot simpler. Use this when possible */ |
| |
| #include <asm/cpufeature.h> |
| |
| .section .altinstructions,"a" |
| .align 8 |
| .quad clear_page |
| .quad clear_page_c |
| .byte X86_FEATURE_REP_GOOD |
| .byte clear_page_end-clear_page |
| .byte clear_page_c_end-clear_page_c |
| .previous |
| |
| .section .altinstr_replacement,"ax" |
| clear_page_c: |
| movl $4096/8,%ecx |
| xorl %eax,%eax |
| rep |
| stosq |
| ret |
| clear_page_c_end: |
| .previous |
