arch/microblaze/lib/fastcopy.S

Source file repositories/reference/linux-study-clean/arch/microblaze/lib/fastcopy.S

File Facts

System
Linux kernel
Corpus path
arch/microblaze/lib/fastcopy.S
Extension
.S
Size
20680 bytes
Lines
667
Domain
Architecture Layer
Bucket
arch/microblaze
Inferred role
Architecture Layer: arch/microblaze
Status
atlas-only

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/linkage.h>
	.text
	.globl	memcpy
	.type  memcpy, @function
	.ent	memcpy

memcpy:
fast_memcpy_ascending:
	/* move d to return register as value of function */
	addi	r3, r5, 0

	addi	r4, r0, 4	/* n = 4 */
	cmpu	r4, r4, r7	/* n = c - n  (unsigned) */
	blti	r4, a_xfer_end	/* if n < 0, less than one word to transfer */

	/* transfer first 0~3 bytes to get aligned dest address */
	andi	r4, r5, 3		/* n = d & 3 */
	/* if zero, destination already aligned */
	beqi	r4, a_dalign_done
	/* n = 4 - n (yields 3, 2, 1 transfers for 1, 2, 3 addr offset) */
	rsubi	r4, r4, 4
	rsub	r7, r4, r7		/* c = c - n adjust c */

a_xfer_first_loop:
	/* if no bytes left to transfer, transfer the bulk */
	beqi	r4, a_dalign_done
	lbui	r11, r6, 0		/* h = *s */
	sbi	r11, r5, 0		/* *d = h */
	addi	r6, r6, 1		/* s++ */
	addi	r5, r5, 1		/* d++ */
	brid	a_xfer_first_loop	/* loop */
	addi	r4, r4, -1		/* n-- (IN DELAY SLOT) */

a_dalign_done:
	addi	r4, r0, 32		/* n = 32 */
	cmpu	r4, r4, r7		/* n = c - n  (unsigned) */
	/* if n < 0, less than one block to transfer */
	blti	r4, a_block_done

a_block_xfer:
	andi	r4, r7, 0xffffffe0	/* n = c & ~31 */
	rsub	r7, r4, r7		/* c = c - n */

	andi	r9, r6, 3		/* t1 = s & 3 */
	/* if temp != 0, unaligned transfers needed */
	bnei	r9, a_block_unaligned

a_block_aligned:
	lwi	r9, r6, 0		/* t1 = *(s + 0) */
	lwi	r10, r6, 4		/* t2 = *(s + 4) */
	lwi	r11, r6, 8		/* t3 = *(s + 8) */
	lwi	r12, r6, 12		/* t4 = *(s + 12) */
	swi	r9, r5, 0		/* *(d + 0) = t1 */
	swi	r10, r5, 4		/* *(d + 4) = t2 */
	swi	r11, r5, 8		/* *(d + 8) = t3 */
	swi	r12, r5, 12		/* *(d + 12) = t4 */
	lwi	r9, r6, 16		/* t1 = *(s + 16) */
	lwi	r10, r6, 20		/* t2 = *(s + 20) */
	lwi	r11, r6, 24		/* t3 = *(s + 24) */
	lwi	r12, r6, 28		/* t4 = *(s + 28) */
	swi	r9, r5, 16		/* *(d + 16) = t1 */
	swi	r10, r5, 20		/* *(d + 20) = t2 */
	swi	r11, r5, 24		/* *(d + 24) = t3 */
	swi	r12, r5, 28		/* *(d + 28) = t4 */
	addi	r6, r6, 32		/* s = s + 32 */
	addi	r4, r4, -32		/* n = n - 32 */
	bneid	r4, a_block_aligned	/* while (n) loop */
	addi	r5, r5, 32		/* d = d + 32 (IN DELAY SLOT) */
	bri	a_block_done

Annotation

Implementation Notes