linux/arch/x86_64/lib/memset.S

/* Copyright 2002 Andi Kleen, SuSE Labs */
/*
 * ISO C memset - set a memory block to a byte value.
 *	
 * rdi   destination
 * rsi   value (char) 
 * rdx   count (bytes) 
 * 
 * rax   original destination
 */	
 	.globl __memset
	.globl memset
	.p2align 4
memset:	
__memset:
	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
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! 2005-04-16 22:20:36 +00:00			`/* Copyright 2002 Andi Kleen, SuSE Labs */`
			`/*`
			`* ISO C memset - set a memory block to a byte value.`
			`*`
			`* rdi destination`
			`* rsi value (char)`
			`* rdx count (bytes)`
			`*`
			`* rax original destination`
			`*/`
			`.globl __memset`
			`.globl memset`
			`.p2align 4`
			`memset:`
			`__memset:`
			`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`