arch/loongarch/lib/memcpy.S

Source file repositories/reference/linux-study-clean/arch/loongarch/lib/memcpy.S

File Facts

System
Linux kernel
Corpus path
arch/loongarch/lib/memcpy.S
Extension
.S
Size
3148 bytes
Lines
203
Domain
Architecture Layer
Bucket
arch/loongarch
Inferred role
Architecture Layer: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <linux/export.h>
#include <asm/alternative-asm.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/cpu.h>
#include <asm/regdef.h>
#include <asm/unwind_hints.h>

.section .noinstr.text, "ax"

SYM_FUNC_START(memcpy)
	/*
	 * Some CPUs support hardware unaligned access
	 */
	ALTERNATIVE	"b __memcpy_generic", \
			"b __memcpy_fast", CPU_FEATURE_UAL
SYM_FUNC_END(memcpy)
SYM_FUNC_ALIAS(__memcpy, memcpy)

EXPORT_SYMBOL(memcpy)
EXPORT_SYMBOL(__memcpy)

_ASM_NOKPROBE(memcpy)
_ASM_NOKPROBE(__memcpy)

/*
 * void *__memcpy_generic(void *dst, const void *src, size_t n)
 *
 * a0: dst
 * a1: src
 * a2: n
 */
SYM_FUNC_START(__memcpy_generic)
	move	a3, a0
	beqz	a2, 2f

1:	ld.b	t0, a1, 0
	st.b	t0, a0, 0
	addi.d	a0, a0, 1
	addi.d	a1, a1, 1
	addi.d	a2, a2, -1
	bgt	a2, zero, 1b

2:	move	a0, a3
	jr	ra
SYM_FUNC_END(__memcpy_generic)
_ASM_NOKPROBE(__memcpy_generic)

	.align	5
SYM_FUNC_START_NOALIGN(__memcpy_small)
	pcaddi	t0, 8
	slli.d	a2, a2, 5
	add.d	t0, t0, a2
	jr	t0

	.align	5
0:	jr	ra

	.align	5
1:	ld.b	t0, a1, 0
	st.b	t0, a0, 0
	jr	ra

	.align	5
2:	ld.h	t0, a1, 0
	st.h	t0, a0, 0
	jr	ra

	.align	5
3:	ld.h	t0, a1, 0

Annotation

Implementation Notes