path: root/arch/powerpc/boot/string.S

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C) Paul Mackerras 1997.
 *
 * NOTE: this code runs in 32 bit mode and is packaged as ELF32.
 */

#include "ppc_asm.h"

	.text
	.globl	strcpy
strcpy:
	addi	r5,r3,-1
	addi	r4,r4,-1
1:	lbzu	r0,1(r4)
	cmpwi	0,r0,0
	stbu	r0,1(r5)
	bne	1b
	blr

	.globl	strncpy
strncpy:
	cmpwi	0,r5,0
	beqlr
	mtctr	r5
	addi	r6,r3,-1
	addi	r4,r4,-1
1:	lbzu	r0,1(r4)
	cmpwi	0,r0,0
	stbu	r0,1(r6)
	bdnzf	2,1b		/* dec ctr, branch if ctr != 0 && !cr0.eq */
	blr

	.globl	strcat
strcat:
	addi	r5,r3,-1
	addi	r4,r4,-1
1:	lbzu	r0,1(r5)
	cmpwi	0,r0,0
	bne	1b
	addi	r5,r5,-1
1:	lbzu	r0,1(r4)
	cmpwi	0,r0,0
	stbu	r0,1(r5)
	bne	1b
	blr

	.globl	strchr
strchr:
	addi	r3,r3,-1
1:	lbzu	r0,1(r3)
	cmpw	0,r0,r4
	beqlr
	cmpwi	0,r0,0
	bne	1b
	li	r3,0
	blr

	.globl	strcmp
strcmp:
	addi	r5,r3,-1
	addi	r4,r4,-1
1:	lbzu	r3,1(r5)
	cmpwi	1,r3,0
	lbzu	r0,1(r4)
	subf.	r3,r0,r3
	beqlr	1
	beq	1b
	blr

	.globl	strncmp
strncmp:
	mtctr	r5
	addi	r5,r3,-1
	addi	r4,r4,-1
1:	lbzu	r3,1(r5)
	cmpwi	1,r3,0
	lbzu	r0,1(r4)
	subf.	r3,r0,r3
	beqlr	1
	bdnzt	eq,1b
	blr

	.globl	strlen
strlen:
	addi	r4,r3,-1
1:	lbzu	r0,1(r4)
	cmpwi	0,r0,0
	bne	1b
	subf	r3,r3,r4
	blr

	.globl	memset
memset:
	rlwimi	r4,r4,8,16,23
	rlwimi	r4,r4,16,0,15
	addi	r6,r3,-4
	cmplwi	0,r5,4
	blt	7f
	stwu	r4,4(r6)
	beqlr
	andi.	r0,r6,3
	add	r5,r0,r5
	subf	r6,r0,r6
	rlwinm	r0,r5,32-2,2,31
	mtctr	r0
	bdz	6f
1:	stwu	r4,4(r6)
	bdnz	1b
6:	andi.	r5,r5,3
7:	cmpwi	0,r5,0
	beqlr
	mtctr	r5
	addi	r6,r6,3
8:	stbu	r4,1(r6)
	bdnz	8b
	blr

	.globl	memmove
memmove:
	cmplw	0,r3,r4
	bgt	backwards_memcpy
	/* fall through */

	.globl	memcpy
memcpy:
	rlwinm.	r7,r5,32-3,3,31		/* r7 = r5 >> 3 */
	addi	r6,r3,-4
	addi	r4,r4,-4
	beq	3f			/* if less than 8 bytes to do */
	andi.	r0,r6,3			/* get dest word aligned */
	mtctr	r7
	bne	5f
	andi.	r0,r4,3			/* check src word aligned too */
	bne	3f
1:	lwz	r7,4(r4)
	lwzu	r8,8(r4)
	stw	r7,4(r6)
	stwu	r8,8(r6)
	bdnz	1b
	andi.	r5,r5,7
2:	cmplwi	0,r5,4
	blt	3f
	lwzu	r0,4(r4)
	addi	r5,r5,-4
	stwu	r0,4(r6)
3:	cmpwi	0,r5,0
	beqlr
	mtctr	r5
	addi	r4,r4,3
	addi	r6,r6,3
4:	lbzu	r0,1(r4)
	stbu	r0,1(r6)
	bdnz	4b
	blr
5:	subfic	r0,r0,4
	cmpw	cr1,r0,r5
	add	r7,r0,r4
	andi.	r7,r7,3			/* will source be word-aligned too? */
	ble	cr1,3b
	bne	3b			/* do byte-by-byte if not */
	mtctr	r0
6:	lbz	r7,4(r4)
	addi	r4,r4,1
	stb	r7,4(r6)
	addi	r6,r6,1
	bdnz	6b
	subf	r5,r0,r5
	rlwinm.	r7,r5,32-3,3,31
	beq	2b
	mtctr	r7
	b	1b

	.globl	backwards_memcpy
backwards_memcpy:
	rlwinm.	r7,r5,32-3,3,31		/* r7 = r5 >> 3 */
	add	r6,r3,r5
	add	r4,r4,r5
	beq	3f
	andi.	r0,r6,3
	mtctr	r7
	bne	5f
	andi.	r0,r4,3
	bne	3f
1:	lwz	r7,-4(r4)
	lwzu	r8,-8(r4)
	stw	r7,-4(r6)
	stwu	r8,-8(r6)
	bdnz	1b
	andi.	r5,r5,7
2:	cmplwi	0,r5,4
	blt	3f
	lwzu	r0,-4(r4)
	subi	r5,r5,4
	stwu	r0,-4(r6)
3:	cmpwi	0,r5,0
	beqlr
	mtctr	r5
4:	lbzu	r0,-1(r4)
	stbu	r0,-1(r6)
	bdnz	4b
	blr
5:	cmpw	cr1,r0,r5
	subf	r7,r0,r4
	andi.	r7,r7,3
	ble	cr1,3b
	bne	3b
	mtctr	r0
6:	lbzu	r7,-1(r4)
	stbu	r7,-1(r6)
	bdnz	6b
	subf	r5,r0,r5
	rlwinm.	r7,r5,32-3,3,31
	beq	2b
	mtctr	r7
	b	1b

	.globl	memchr
memchr:
	cmpwi	0,r5,0
	blelr
	mtctr	r5
	addi	r3,r3,-1
1:	lbzu	r0,1(r3)
	cmpw	r0,r4
	beqlr
	bdnz	1b
	li	r3,0
	blr

	.globl	memcmp
memcmp:
	cmpwi	0,r5,0
	ble	2f
	mtctr	r5
	addi	r6,r3,-1
	addi	r4,r4,-1
1:	lbzu	r3,1(r6)
	lbzu	r0,1(r4)
	subf.	r3,r0,r3
	bdnzt	2,1b
	blr
2:	li	r3,0
	blr


/*
 * Flush the dcache and invalidate the icache for a range of addresses.
 *
 * flush_cache(addr, len)
 */
	.global	flush_cache
flush_cache:
	addi	4,4,0x1f	/* len = (len + 0x1f) / 0x20 */
	rlwinm.	4,4,27,5,31
	mtctr	4
	beqlr
1:	dcbf	0,3
	icbi	0,3
	addi	3,3,0x20
	bdnz	1b
	sync
	isync
	blr