diff options
Diffstat (limited to 'arch/nds32/lib/memset.S')
| -rw-r--r-- | arch/nds32/lib/memset.S | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/arch/nds32/lib/memset.S b/arch/nds32/lib/memset.S new file mode 100644 index 000000000000..193cb6ce21a9 --- /dev/null +++ b/arch/nds32/lib/memset.S @@ -0,0 +1,33 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2005-2017 Andes Technology Corporation + +#include <linux/linkage.h> + + .text +ENTRY(memset) + move $r5, $r0 ! Return value + beqz $r2, end_memset ! Exit when len = 0 + srli $p1, $r2, 2 ! $p1 is how many words to copy + andi $r2, $r2, 3 ! How many bytes are less than a word + beqz $p1, byte_set ! When n is less than a word + + ! set $r1 from ??????ab to abababab + andi $r1, $r1, #0x00ff ! $r1 = 000000ab + slli $p0, $r1, #8 ! $p0 = 0000ab00 + or $r1, $r1, $p0 ! $r1 = 0000abab + slli $p0, $r1, #16 ! $p0 = abab0000 + or $r1, $r1, $p0 ! $r1 = abababab +word_set: + addi $p1, $p1, #-1 ! How many words left to copy + smw.bim $r1, [$r0], $r1 ! Copy the word to det + bnez $p1, word_set ! Still words to set, continue looping + beqz $r2, end_memset ! No left byte to set +byte_set: ! Less than 4 bytes left to set + addi $r2, $r2, #-1 ! Decrease len by 1 + sbi.bi $r1, [$r0], #1 ! Set data of the next byte to $r1 + bnez $r2, byte_set ! Still bytes left to set +end_memset: + move $r0, $r5 + ret + +ENDPROC(memset) |