cyclic shift

gistfile1.txt

gcc -O3 -S shift.c

shift.c

unsigned int cshift (const unsigned int src, const unsigned char shift) {
  return (src >> shift) | (src << (sizeof(unsigned int)*8 - shift));
}

main() {
  cshift(0xabcd, 3);
}

shift.s

	.file	"shift.c"
	.text
	.p2align 4,,15
	.globl	cshift
	.type	cshift, @function
cshift:
.LFB0:
	.cfi_startproc
	movzbl	%sil, %eax
	movl	$32, %ecx
	subl	%eax, %ecx
	movl	%edi, %eax
	sall	%cl, %eax
	movl	%esi, %ecx
	shrl	%cl, %edi
	orl	%edi, %eax
	ret
	.cfi_endproc
.LFE0:
	.size	cshift, .-cshift
	.section	.text.startup,"ax",@progbits
	.p2align 4,,15
	.globl	main
	.type	main, @function
main:
.LFB1:
	.cfi_startproc
	rep
	ret
	.cfi_endproc
.LFE1:
	.size	main, .-main
	.ident	"GCC: (Debian 4.6.2-5) 4.6.2"
	.section	.note.GNU-stack,"",@progbits