__asm__ __volatile__()

in include/asm/uaccess.h [76:128]

• 51 lines of code
• 5 McCabe index (conditional complexity)

	__asm__ __volatile__(                   \
	"1:	"op"    %1,[%2]\n"		\
	"2:	;nop\n"				\
	"	.section .fixup, \"ax\"\n"	\
	"	.align 4\n"			\
	"3:	# return -EFAULT\n"		\
	"	mov %0, %3\n"			\
	"	# zero out dst ptr\n"		\
	"	mov %1,  0\n"			\
	"	j   2b\n"			\
	"	.previous\n"			\
	"	.section __ex_table, \"a\"\n"	\
	"	.align 4\n"			\
	"	.word 1b,3b\n"			\
	"	.previous\n"			\
						\
	: "+r" (ret), "=r" (dst)		\
	: "r" (src), "ir" (-EFAULT))

#define __arc_get_user_one_64(dst, src, ret)	\
	__asm__ __volatile__(                   \
	"1:	ld   %1,[%2]\n"			\
	"4:	ld  %R1,[%2, 4]\n"		\
	"2:	;nop\n"				\
	"	.section .fixup, \"ax\"\n"	\
	"	.align 4\n"			\
	"3:	# return -EFAULT\n"		\
	"	mov %0, %3\n"			\
	"	# zero out dst ptr\n"		\
	"	mov %1,  0\n"			\
	"	mov %R1, 0\n"			\
	"	j   2b\n"			\
	"	.previous\n"			\
	"	.section __ex_table, \"a\"\n"	\
	"	.align 4\n"			\
	"	.word 1b,3b\n"			\
	"	.word 4b,3b\n"			\
	"	.previous\n"			\
						\
	: "+r" (ret), "=r" (dst)		\
	: "r" (src), "ir" (-EFAULT))

#define __put_user_fn(sz, u, k)					\
({								\
	long __ret = 0;	/* success by default */	\
	switch (sz) {						\
	case 1: __arc_put_user_one(*(k), u, "stb", __ret); break;	\
	case 2: __arc_put_user_one(*(k), u, "stw", __ret); break;	\
	case 4: __arc_put_user_one(*(k), u, "st", __ret);  break;	\
	case 8: __arc_put_user_one_64(*(k), u, __ret);     break;	\
	}							\
	__ret;							\
})