Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/* Copyright 2002 Andi Kleen, SuSE Labs */

#include <linux/linkage.h>
#include <asm/dwarf2.h>

/*
 * ISO C memset - set a memory block to a byte value.
 *      
 * rdi   destination
 * rsi   value (char) 
 * rdx   count (bytes) 
 * 
 * rax   original destination
 */     
        ALIGN
memset_c:
        CFI_STARTPROC
        movq %rdi,%r9
        movl %edx,%r8d
        andl $7,%r8d
        movl %edx,%ecx
        shrl $3,%ecx
        /* expand byte value  */
        movzbl %sil,%esi
        movabs $0x0101010101010101,%rax
        mulq %rsi               /* with rax, clobbers rdx */
        rep stosq
        movl %r8d,%ecx
        rep stosb
        movq %r9,%rax
        ret
        CFI_ENDPROC
ENDPROC(memset_c)

ENTRY(memset)
ENTRY(__memset)
        CFI_STARTPROC
        movq %rdi,%r10
        movq %rdx,%r11

        /* expand byte value  */
        movzbl %sil,%ecx
        movabs $0x0101010101010101,%rax
        mul    %rcx             /* with rax, clobbers rdx */

        /* align dst */
        movl  %edi,%r9d
        andl  $7,%r9d
        jnz  .Lbad_alignment
        CFI_REMEMBER_STATE
.Lafter_bad_alignment:

        movl %r11d,%ecx
        shrl $6,%ecx
        jz       .Lhandle_tail

        .p2align 4
.Lloop_64:
        decl   %ecx
        movq  %rax,(%rdi)
        movq  %rax,8(%rdi)
        movq  %rax,16(%rdi)
        movq  %rax,24(%rdi)
        movq  %rax,32(%rdi)
        movq  %rax,40(%rdi)
        movq  %rax,48(%rdi)
        movq  %rax,56(%rdi)
        leaq  64(%rdi),%rdi
        jnz    .Lloop_64

        /* Handle tail in loops. The loops should be faster than hard
           to predict jump tables. */
        .p2align 4
.Lhandle_tail:
        movl    %r11d,%ecx
        andl    $63&(~7),%ecx
        jz              .Lhandle_7
        shrl    $3,%ecx
        .p2align 4
.Lloop_8:
        decl   %ecx
        movq  %rax,(%rdi)
        leaq  8(%rdi),%rdi
        jnz    .Lloop_8

.Lhandle_7:
        movl    %r11d,%ecx
        andl    $7,%ecx
        jz      .Lende
        .p2align 4
.Lloop_1:
        decl    %ecx
        movb    %al,(%rdi)
        leaq    1(%rdi),%rdi
        jnz     .Lloop_1

.Lende:
        movq    %r10,%rax
        ret

        CFI_RESTORE_STATE
.Lbad_alignment:
        cmpq $7,%r11
        jbe     .Lhandle_7
        movq %rax,(%rdi)        /* unaligned store */
        movq $8,%r8
        subq %r9,%r8
        addq %r8,%rdi
        subq %r8,%r11
        jmp .Lafter_bad_alignment
.Lfinal:
        CFI_ENDPROC
ENDPROC(memset)
ENDPROC(__memset)

        /* Some CPUs run faster using the string instructions.
           It is also a lot simpler. Use this when possible */

#include <asm/cpufeature.h>

        .section .altinstr_replacement,"ax"
1:      .byte 0xeb                              /* jmp <disp8> */
        .byte (memset_c - memset) - (2f - 1b)   /* offset */
2:
        .previous
        .section .altinstructions,"a"
        .align 8
        .quad memset
        .quad 1b
        .byte X86_FEATURE_REP_GOOD
        .byte .Lfinal - memset
        .byte 2b - 1b
        .previous