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38
by Michael Hope
Added the XScale specific routines from Newlib 1.19.0 |
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#include <string.h> |
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#include "xscale.h" |
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void * |
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memchr (const void *start, int c, size_t len) |
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{
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const char *str = start; |
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if (len == 0) |
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return 0; |
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asm (PRELOADSTR ("%0") : : "r" (start)); |
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c &= 0xff; |
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#ifndef __OPTIMIZE_SIZE__
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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 == c) |
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return (void *)str; |
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}
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while (((long)str & 3) != 0 && --len > 0); |
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}
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if (len > 3) |
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{
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unsigned int c2 = c + (c << 8); |
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c2 += c2 << 16; |
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/* Load two constants:
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R7 = 0xfefefeff [ == ~(0x80808080 << 1) ]
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R6 = 0x80808080 */
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asm ( |
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"mov r6, #0x80\n\ |
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add r6, r6, #0x8000\n\ |
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add r6, r6, r6, lsl #16\n\ |
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mvn r7, r6, lsl #1\n\ |
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\n\ |
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0:\n\ |
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cmp %1, #0x7\n\ |
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bls 1f\n\ |
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\n\ |
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ldmia %0!, { r3, r9 }\n\ |
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" PRELOADSTR ("%0") "\n\ |
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sub %1, %1, #8\n\ |
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eor r3, r3, %2\n\ |
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eor r9, r9, %2\n\ |
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add r2, r3, r7\n\ |
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add r8, r9, r7\n\ |
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bic r2, r2, r3\n\ |
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bic r8, r8, r9\n\ |
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and r1, r2, r6\n\ |
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and r9, r8, r6\n\ |
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orrs r1, r1, r9\n\ |
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beq 0b\n\ |
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\n\ |
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add %1, %1, #8\n\ |
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sub %0, %0, #8\n\ |
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1:\n\ |
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cmp %1, #0x3\n\ |
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bls 2f\n\ |
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\n\ |
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ldr r3, [%0], #4\n\ |
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" PRELOADSTR ("%0") "\n\ |
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sub %1, %1, #4\n\ |
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eor r3, r3, %2\n\ |
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add r2, r3, r7\n\ |
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bic r2, r2, r3\n\ |
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ands r1, r2, r6\n\ |
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beq 1b\n\ |
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\n\ |
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sub %0, %0, #4\n\ |
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add %1, %1, #4\n\ |
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2:\n\ |
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"
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: "=&r" (str), "=&r" (len) |
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: "r" (c2), "0" (str), "1" (len) |
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: "r1", "r2", "r3", "r6", "r7", "r8", "r9", "cc"); |
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}
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#endif
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while (len-- > 0) |
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{
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if (*str == c) |
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return (void *)str; |
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str++; |
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}
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return 0; |
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}
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