70 lines
1.4 KiB
ArmAsm
70 lines
1.4 KiB
ArmAsm
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/* These functions are almost verbatim FreeBSD code (even if the header of
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one file mentiones NetBSD), just wrapped in the minimum required code to
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make them work under the MS AMD64 ABI.
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See FreeBSD src/lib/libc/amd64/string/memset.S */
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/*
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* Written by J.T. Conklin <jtc@NetBSD.org>.
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* Public domain.
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* Adapted for NetBSD/x86_64 by
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* Frank van der Linden <fvdl@wasabisystems.com>
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*/
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.globl memset
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.seh_proc memset
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memset:
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movq %rsi,8(%rsp)
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movq %rdi,16(%rsp)
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.seh_endprologue
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movq %rcx,%rdi
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movq %rdx,%rsi
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movq %r8,%rdx
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movq %rsi,%rax
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andq $0xff,%rax
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movq %rdx,%rcx
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movq %rdi,%r11
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cld /* set fill direction forward */
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/* if the string is too short, it's really not worth the
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* overhead of aligning to word boundries, etc. So we jump to
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* a plain unaligned set. */
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cmpq $0x0f,%rcx
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jle L1
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movb %al,%ah /* copy char to all bytes in word */
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movl %eax,%edx
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sall $16,%eax
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orl %edx,%eax
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movl %eax,%edx
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salq $32,%rax
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orq %rdx,%rax
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movq %rdi,%rdx /* compute misalignment */
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negq %rdx
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andq $7,%rdx
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movq %rcx,%r8
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subq %rdx,%r8
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movq %rdx,%rcx /* set until word aligned */
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rep
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stosb
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movq %r8,%rcx
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shrq $3,%rcx /* set by words */
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rep
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stosq
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movq %r8,%rcx /* set remainder by bytes */
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andq $7,%rcx
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L1: rep
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stosb
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movq %r11,%rax
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movq 8(%rsp),%rsi
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movq 16(%rsp),%rdi
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ret
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.seh_endproc
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