118 lines
2.1 KiB
ArmAsm
118 lines
2.1 KiB
ArmAsm
/*
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* linux/arch/m32r/strlen.S -- strlen code.
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*
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* Copyright (C) 2001 Hirokazu Takata
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*
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* size_t strlen(const char *s);
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*
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#ifdef CONFIG_ISA_DUAL_ISSUE
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.text
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ENTRY(strlen)
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mv r6, r0 || ldi r2, #0
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and3 r0, r0, #3
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bnez r0, strlen_byte
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;
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strlen_word:
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ld r0, @r6+
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;
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seth r5, #high(0x01010101)
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or3 r5, r5, #low(0x01010101)
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sll3 r7, r5, #7
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strlen_word_loop:
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ld r1, @r6+ || not r4, r0
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sub r0, r5 || and r4, r7
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and r4, r0
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bnez r4, strlen_last_bytes
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ld r0, @r6+ || not r4, r1
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sub r1, r5 || and r4, r7
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and r4, r1 || addi r2, #4
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bnez r4, strlen_last_bytes
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addi r2, #4 || bra.s strlen_word_loop
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; NOTE: If a null char. exists, return 0.
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; if ((x - 0x01010101) & ~x & 0x80808080)
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; return 0;
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;
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strlen_byte:
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ldb r1, @r6 || addi r6, #1
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beqz r1, strlen_exit
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addi r2, #1 || bra.s strlen_byte
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;
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strlen_last_bytes:
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ldi r0, #4 || addi r6, #-8
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;
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strlen_byte_loop:
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ldb r1, @r6 || addi r6, #1
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addi r0, #-1 || cmpz r1
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bc.s strlen_exit || cmpz r0
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addi r2, #1 || bnc.s strlen_byte_loop
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;
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strlen_exit:
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mv r0, r2 || jmp r14
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#else /* not CONFIG_ISA_DUAL_ISSUE */
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.text
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ENTRY(strlen)
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mv r6, r0
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ldi r2, #0
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and3 r0, r0, #3
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bnez r0, strlen_byte
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;
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strlen_word:
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ld r0, @r6+
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;
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seth r5, #high(0x01010101)
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or3 r5, r5, #low(0x01010101)
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sll3 r7, r5, #7
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strlen_word_loop:
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ld r1, @r6+
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not r4, r0 ; NOTE: If a null char. exists, return 0.
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sub r0, r5 ; if ((x - 0x01010101) & ~x & 0x80808080)
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and r4, r7 ; return 0;
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and r4, r0
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bnez r4, strlen_last_bytes
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addi r2, #4
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;
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ld r0, @r6+
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not r4, r1 ; NOTE: If a null char. exists, return 0.
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sub r1, r5 ; if ((x - 0x01010101) & ~x & 0x80808080)
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and r4, r7 ; return 0;
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and r4, r1
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bnez r4, strlen_last_bytes
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addi r2, #4
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bra strlen_word_loop
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;
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strlen_byte:
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ldb r1, @r6
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addi r6, #1
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beqz r1, strlen_exit
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addi r2, #1
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bra strlen_byte
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;
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strlen_last_bytes:
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ldi r0, #4
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addi r6, #-8
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;
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strlen_byte_loop:
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ldb r1, @r6
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addi r6, #1
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addi r0, #-1
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beqz r1, strlen_exit
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addi r2, #1
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bnez r0, strlen_byte_loop
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;
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strlen_exit:
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mv r0, r2
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jmp r14
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#endif /* not CONFIG_ISA_DUAL_ISSUE */
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.end
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