101 lines
1.5 KiB
C
101 lines
1.5 KiB
C
#if defined __thumb__ || defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
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#include "../../string/strlen.c"
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#else
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#include <string.h>
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#include "xscale.h"
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size_t
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strlen (const char *str)
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{
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_CONST char *start = str;
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/* Skip unaligned part. */
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if ((long)str & 3)
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{
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str--;
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do
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{
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if (*++str == '\0')
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goto out;
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}
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while ((long)str & 3);
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}
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/* Load two constants:
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R4 = 0xfefefeff [ == ~(0x80808080 << 1) ]
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R5 = 0x80808080 */
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asm ("mov r5, #0x80\n\
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add r5, r5, #0x8000\n\
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add r5, r5, r5, lsl #16\n\
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mvn r4, r5, lsl #1\n\
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"
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#if defined __ARM_ARCH_5__ || defined __ARM_ARCH_5T__ || defined __ARM_ARCH_5E__ || defined __ARM_ARCH_5TE__
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" tst %0, #0x7\n\
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ldreqd r6, [%0]\n\
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beq 1f\n\
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ldr r2, [%0]\n\
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add r3, r2, r4\n\
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bic r3, r3, r2\n\
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ands r2, r3, r5\n\
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bne 2f\n\
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sub %0, %0, #4\n\
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\n\
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0:\n\
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ldrd r6, [%0, #8]!\n\
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"
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PRELOADSTR ("%0")
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"\n\
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1:\n\
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add r3, r6, r4\n\
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add r2, r7, r4\n\
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bic r3, r3, r6\n\
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bic r2, r2, r7\n\
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and r3, r3, r5\n\
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and r2, r2, r5\n\
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orrs r3, r2, r3\n\
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beq 0b\n\
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"
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#else
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" sub %0, %0, #4\n\
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\n\
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0:\n\
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ldr r6, [%0, #4]!\n\
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"
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PRELOADSTR ("%0")
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"\n\
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add r3, r6, r4\n\
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bic r3, r3, r6\n\
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ands r3, r3, r5\n\
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beq 0b\n\
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"
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#endif /* __ARM_ARCH_5[T][E]__ */
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"\n\
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2:\n\
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ldrb r3, [%0]\n\
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cmp r3, #0x0\n\
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beq 1f\n\
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\n\
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0:\n\
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ldrb r3, [%0, #1]!\n\
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"
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PRELOADSTR ("%0")
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"\n\
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cmp r3, #0x0\n\
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bne 0b\n\
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1:\n\
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"
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: "=r" (str) : "0" (str) : "r2", "r3", "r4", "r5", "r6", "r7");
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out:
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return str - start;
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}
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#endif
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