Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) // Copyright (C) 2005-2017 Andes Technology Corporation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) #include <linux/linkage.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7)   void *memmove(void *dst, const void *src, int n);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9)   dst: $r0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)   src: $r1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11)   n  : $r2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)   ret: $r0 - pointer to the memory area dst.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) 	.text
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) ENTRY(memmove)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 	move	$r5, $r0		! Set return value = det
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 	beq	$r0, $r1, exit_memcpy	! Exit when det = src
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 	beqz	$r2, exit_memcpy	! Exit when n = 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 	pushm	$t0, $t1		! Save reg
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 	srli	$p1, $r2, #2		! $p1 is how many words to copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 	! Avoid data lost when memory overlap
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 	! Copy data reversely when src < dst
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 	slt	$p0, $r0, $r1		! check if $r0 < $r1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 	beqz	$p0, do_reverse		! branch if dst > src
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 	! No reverse, dst < src
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 	andi	$r2, $r2, #3		! How many bytes are less than a word
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 	li	$t0, #1			! Determining copy direction in byte_cpy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 	beqz	$p1, byte_cpy		! When n is less than a word
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) word_cpy:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 	lmw.bim	$p0, [$r1], $p0		! Read a word from src
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 	addi	$p1, $p1, #-1		! How many words left to copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 	smw.bim	$p0, [$r0], $p0		! Copy the word to det
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 	bnez	$p1, word_cpy		! If remained words > 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 	beqz	$r2, end_memcpy		! No left bytes to copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 	b	byte_cpy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) do_reverse:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 	add	$r0, $r0, $r2		! Start with the end of $r0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 	add	$r1, $r1, $r2		! Start with the end of $r1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 	andi	$r2, $r2, #3		! How many bytes are less than a word
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 	li	$t0, #-1		! Determining copy direction in byte_cpy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 	beqz	$p1, reverse_byte_cpy	! When n is less than a word
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) reverse_word_cpy:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 	lmw.adm	$p0, [$r1], $p0		! Read a word from src
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 	addi	$p1, $p1, #-1		! How many words left to copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 	smw.adm	$p0, [$r0], $p0		! Copy the word to det
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 	bnez	$p1, reverse_word_cpy	! If remained words > 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) 	beqz	$r2, end_memcpy		! No left bytes to copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) reverse_byte_cpy:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) 	addi	$r0, $r0, #-1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 	addi	$r1, $r1, #-1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) byte_cpy:				! Less than 4 bytes to copy now
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) 	lb.bi	$p0, [$r1], $t0		! Read a byte from src
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) 	addi	$r2, $r2, #-1		! How many bytes left to copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) 	sb.bi	$p0, [$r0], $t0		! copy the byte to det
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) 	bnez	$r2, byte_cpy		! If remained bytes > 0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) end_memcpy:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) 	popm	$t0, $t1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) exit_memcpy:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) 	move	$r0, $r5
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) 	ret
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) ENDPROC(memmove)