root/arch/csky/abiv2/strlen.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
   3 
   4 #include <linux/linkage.h>
   5 #include "sysdep.h"
   6 
   7 ENTRY(strlen)
   8         /* Check if the start addr is aligned.  */
   9         mov     r3, r0
  10         andi    r1, r0, 3
  11         movi    r2, 4
  12         movi    r0, 0
  13         bnez    r1, .L_start_not_aligned
  14 
  15         LABLE_ALIGN
  16 .L_start_addr_aligned:
  17         /* Check if all the bytes in the word are not zero.  */
  18         ldw     r1, (r3)
  19         tstnbz  r1
  20         bf      .L_string_tail
  21 
  22         ldw     r1, (r3, 4)
  23         addi    r0, 4
  24         tstnbz  r1
  25         bf      .L_string_tail
  26 
  27         ldw     r1, (r3, 8)
  28         addi    r0, 4
  29         tstnbz  r1
  30         bf      .L_string_tail
  31 
  32         ldw     r1, (r3, 12)
  33         addi    r0, 4
  34         tstnbz  r1
  35         bf      .L_string_tail
  36 
  37         ldw     r1, (r3, 16)
  38         addi    r0, 4
  39         tstnbz  r1
  40         bf      .L_string_tail
  41 
  42         ldw     r1, (r3, 20)
  43         addi    r0, 4
  44         tstnbz  r1
  45         bf      .L_string_tail
  46 
  47         ldw     r1, (r3, 24)
  48         addi    r0, 4
  49         tstnbz  r1
  50         bf      .L_string_tail
  51 
  52         ldw     r1, (r3, 28)
  53         addi    r0, 4
  54         tstnbz  r1
  55         bf      .L_string_tail
  56 
  57         addi    r0, 4
  58         addi    r3, 32
  59         br      .L_start_addr_aligned
  60 
  61 .L_string_tail:
  62 # ifdef __CSKYBE__
  63         xtrb0   r3, r1
  64         bez     r3, .L_return
  65         addi    r0, 1
  66         xtrb1   r3, r1
  67         bez     r3, .L_return
  68         addi    r0, 1
  69         xtrb2   r3, r1
  70         bez     r3, .L_return
  71         addi    r0, 1
  72 # else
  73         xtrb3   r3, r1
  74         bez     r3, .L_return
  75         addi    r0, 1
  76         xtrb2   r3, r1
  77         bez     r3, .L_return
  78         addi    r0, 1
  79         xtrb1   r3, r1
  80         bez     r3, .L_return
  81         addi    r0, 1
  82 # endif /* !__CSKYBE__ */
  83 
  84 .L_return:
  85         rts
  86 
  87 .L_start_not_aligned:
  88         sub     r2, r2, r1
  89 .L_start_not_aligned_loop:
  90         ldb     r1, (r3)
  91         PRE_BNEZAD (r2)
  92         addi    r3, 1
  93         bez     r1, .L_return
  94         addi    r0, 1
  95         BNEZAD (r2, .L_start_not_aligned_loop)
  96         br      .L_start_addr_aligned
  97 ENDPROC(strlen)