Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*
 *  linux/arch/m32r/strlen.S --  strlen code.
 *
 *  Copyright (C) 2001  Hirokazu Takata
 *
 *  size_t strlen(const char *s);
 *
 */

#include <linux/linkage.h>
#include <asm/assembler.h>

#ifdef CONFIG_ISA_DUAL_ISSUE

        .text
ENTRY(strlen)
        mv      r6, r0              ||  ldi     r2, #0
        and3    r0, r0, #3
        bnez    r0, strlen_byte
;
strlen_word:
        ld      r0, @r6+
;
        seth    r5, #high(0x01010101)
        or3     r5, r5, #low(0x01010101)
        sll3    r7, r5, #7
strlen_word_loop:
        ld      r1, @r6+            ||  not     r4, r0
        sub     r0, r5              ||  and     r4, r7
        and     r4, r0
        bnez    r4, strlen_last_bytes
        ld      r0, @r6+            ||  not     r4, r1
        sub     r1, r5              ||  and     r4, r7
        and     r4, r1              ||  addi    r2, #4
        bnez    r4, strlen_last_bytes
        addi    r2, #4              ||  bra.s   strlen_word_loop

        ; NOTE: If a null char. exists, return 0.
        ; if ((x - 0x01010101) & ~x & 0x80808080)
        ;     return 0;
;
strlen_byte:
        ldb     r1, @r6             ||  addi    r6, #1
        beqz    r1, strlen_exit
        addi    r2, #1              ||  bra.s   strlen_byte
;
strlen_last_bytes:
        ldi     r0, #4              ||  addi    r6, #-8
;
strlen_byte_loop:
        ldb     r1, @r6             ||  addi    r6, #1
        addi    r0, #-1             ||  cmpz    r1
        bc.s    strlen_exit         ||  cmpz    r0
        addi    r2, #1              ||  bnc.s   strlen_byte_loop
;
strlen_exit:
        mv      r0, r2              ||  jmp     r14

#else /* not CONFIG_ISA_DUAL_ISSUE */

        .text
ENTRY(strlen)
        mv      r6, r0
        ldi     r2, #0
        and3    r0, r0, #3
        bnez    r0, strlen_byte
;
strlen_word:
        ld      r0, @r6+
;
        seth    r5, #high(0x01010101)
        or3     r5, r5, #low(0x01010101)
        sll3    r7, r5, #7
strlen_word_loop:
        ld      r1, @r6+
        not     r4, r0          ; NOTE: If a null char. exists, return 0.
        sub     r0, r5          ; if ((x - 0x01010101) & ~x & 0x80808080)
        and     r4, r7          ;     return 0;
        and     r4, r0
        bnez    r4, strlen_last_bytes
        addi    r2, #4
;
        ld      r0, @r6+
        not     r4, r1          ; NOTE: If a null char. exists, return 0.
        sub     r1, r5          ; if ((x - 0x01010101) & ~x & 0x80808080)
        and     r4, r7          ;     return 0;
        and     r4, r1
        bnez    r4, strlen_last_bytes
        addi    r2, #4
        bra     strlen_word_loop
;
strlen_byte:
        ldb     r1, @r6
        addi    r6, #1
        beqz    r1, strlen_exit
        addi    r2, #1
        bra     strlen_byte
;
strlen_last_bytes:
        ldi     r0, #4
        addi    r6, #-8
;
strlen_byte_loop:
        ldb     r1, @r6
        addi    r6, #1
        addi    r0, #-1
        beqz    r1, strlen_exit
        addi    r2, #1
        bnez    r0, strlen_byte_loop
;
strlen_exit:
        mv      r0, r2
        jmp     r14

#endif /* not CONFIG_ISA_DUAL_ISSUE */

        .end