arch/m32r/lib/strlen.S

   1 /*
   2  *  linux/arch/m32r/strlen.S --  strlen code.
   3  *
   4  *  Copyright (C) 2001  Hirokazu Takata
   5  *
   6  *  size_t strlen(const char *s);
   7  *
   8  */
   9 /* $Id$ */
  10
  11
  12 #include <linux/config.h>
  13 #include <linux/linkage.h>
  14 #include <asm/assembler.h>
  15
  16 #ifdef CONFIG_ISA_DUAL_ISSUE
  17
  18         .text
  19 ENTRY(strlen)
  20         mv      r6, r0              ||  ldi     r2, #0
  21         and3    r0, r0, #3
  22         bnez    r0, strlen_byte
  23 ;
  24 strlen_word:
  25         ld      r0, @r6+
  26 ;
  27         seth    r5, #high(0x01010101)
  28         or3     r5, r5, #low(0x01010101)
  29         sll3    r7, r5, #7
  30 strlen_word_loop:
  31         ld      r1, @r6+            ||  not     r4, r0
  32         sub     r0, r5              ||  and     r4, r7
  33         and     r4, r0
  34         bnez    r4, strlen_last_bytes
  35         ld      r0, @r6+            ||  not     r4, r1
  36         sub     r1, r5              ||  and     r4, r7
  37         and     r4, r1              ||  addi    r2, #4
  38         bnez    r4, strlen_last_bytes
  39         addi    r2, #4              ||  bra.s   strlen_word_loop
  40
  41         ; NOTE: If a null char. exists, return 0.
  42         ; if ((x - 0x01010101) & ~x & 0x80808080)
  43         ;     return 0;
  44 ;
  45 strlen_byte:
  46         ldb     r1, @r6             ||  addi    r6, #1
  47         beqz    r1, strlen_exit
  48         addi    r2, #1              ||  bra.s   strlen_byte
  49 ;
  50 strlen_last_bytes:
  51         ldi     r0, #4              ||  addi    r6, #-8
  52 ;
  53 strlen_byte_loop:
  54         ldb     r1, @r6             ||  addi    r6, #1
  55         addi    r0, #-1             ||  cmpz    r1
  56         bc.s    strlen_exit         ||  cmpz    r0
  57         addi    r2, #1              ||  bnc.s   strlen_byte_loop
  58 ;
  59 strlen_exit:
  60         mv      r0, r2              ||  jmp     r14
  61
  62 #else /* not CONFIG_ISA_DUAL_ISSUE */
  63
  64         .text
  65 ENTRY(strlen)
  66         mv      r6, r0
  67         ldi     r2, #0
  68         and3    r0, r0, #3
  69         bnez    r0, strlen_byte
  70 ;
  71 strlen_word:
  72         ld      r0, @r6+
  73 ;
  74         seth    r5, #high(0x01010101)
  75         or3     r5, r5, #low(0x01010101)
  76         sll3    r7, r5, #7
  77 strlen_word_loop:
  78         ld      r1, @r6+
  79         not     r4, r0          ; NOTE: If a null char. exists, return 0.
  80         sub     r0, r5          ; if ((x - 0x01010101) & ~x & 0x80808080)
  81         and     r4, r7          ;     return 0;
  82         and     r4, r0
  83         bnez    r4, strlen_last_bytes
  84         addi    r2, #4
  85 ;
  86         ld      r0, @r6+
  87         not     r4, r1          ; NOTE: If a null char. exists, return 0.
  88         sub     r1, r5          ; if ((x - 0x01010101) & ~x & 0x80808080)
  89         and     r4, r7          ;     return 0;
  90         and     r4, r1
  91         bnez    r4, strlen_last_bytes
  92         addi    r2, #4
  93         bra     strlen_word_loop
  94 ;
  95 strlen_byte:
  96         ldb     r1, @r6
  97         addi    r6, #1
  98         beqz    r1, strlen_exit
  99         addi    r2, #1
 100         bra     strlen_byte
 101 ;
 102 strlen_last_bytes:
 103         ldi     r0, #4
 104         addi    r6, #-8
 105 ;
 106 strlen_byte_loop:
 107         ldb     r1, @r6
 108         addi    r6, #1
 109         addi    r0, #-1
 110         beqz    r1, strlen_exit
 111         addi    r2, #1
 112         bnez    r0, strlen_byte_loop
 113 ;
 114 strlen_exit:
 115         mv      r0, r2
 116         jmp     r14
 117
 118 #endif /* not CONFIG_ISA_DUAL_ISSUE */
 119
 120         .end