mirror of
https://github.com/autc04/Retro68.git
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74 lines
1.1 KiB
C
74 lines
1.1 KiB
C
#if defined __thumb__
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#include "../../string/strchr.c"
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#else
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#include <string.h>
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#include "xscale.h"
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char *
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strchr (const char *s, int c)
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{
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unsigned int c2;
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asm (PRELOADSTR ("%0") : : "r" (s));
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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)s & 3)
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{
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s--;
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do
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{
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int c2 = *++s;
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if (c2 == c)
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return (char *)s;
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if (c2 == '\0')
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return 0;
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}
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while (((long)s & 3) != 0);
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}
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c2 = c + (c << 8);
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c2 += c2 << 16;
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/* Load two constants:
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R6 = 0xfefefeff [ == ~(0x80808080 << 1) ]
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R5 = 0x80808080 */
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asm (PRELOADSTR ("%0") "\n\
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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 r6, r5, lsl #1\n\
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\n\
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sub %0, %0, #4\n\
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0:\n\
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ldr r1, [%0, #4]!\n\
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" PRELOADSTR ("%0") "\n\
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add r3, r1, r6\n\
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bic r3, r3, r1\n\
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ands r2, r3, r5\n\
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bne 1f\n\
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eor r2, r1, %1\n\
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add r3, r2, r6\n\
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bic r3, r3, r2\n\
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ands r1, r3, r5\n\
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beq 0b\n\
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1:"
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: "=&r" (s)
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: "r" (c2), "0" (s)
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: "r1", "r2", "r3", "r5", "r6", "cc");
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#endif
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while (*s && *s != c)
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s++;
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if (*s == c)
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return (char *)s;
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return NULL;
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}
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#endif
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