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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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#undef strcmp
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int
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strcmp (const char *s1, const char *s2) |
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{
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asm (PRELOADSTR ("%0") : : "r" (s1)); |
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asm (PRELOADSTR ("%0") : : "r" (s2)); |
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#ifndef __OPTIMIZE_SIZE__
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if (((long)s1 & 3) == ((long)s2 & 3)) |
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{
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int result; |
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/* Skip unaligned part. */
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while ((long)s1 & 3) |
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{
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if (*s1 == '\0' || *s1 != *s2) |
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goto out; |
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s1++; |
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s2++; |
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}
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/* Load two constants:
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lr = 0xfefefeff [ == ~(0x80808080 << 1) ]
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ip = 0x80808080 */
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asm ( |
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"ldr r2, [%1, #0]\n\ |
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ldr r3, [%2, #0]\n\ |
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cmp r2, r3\n\ |
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bne 2f\n\ |
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\n\ |
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mov ip, #0x80\n\ |
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add ip, ip, #0x8000\n\ |
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add ip, ip, ip, lsl #16\n\ |
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mvn lr, ip, lsl #1\n\ |
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\n\ |
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0:\n\ |
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ldr r2, [%1, #0]\n\ |
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add r3, r2, lr\n\ |
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bic r3, r3, r2\n\ |
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tst r3, ip\n\ |
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beq 1f\n\ |
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mov %0, #0x0\n\ |
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b 3f\n\ |
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1:\n\ |
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ldr r2, [%1, #4]!\n\ |
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ldr r3, [%2, #4]!\n\ |
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" PRELOADSTR("%1") "\n\ |
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" PRELOADSTR("%2") "\n\ |
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cmp r2, r3\n\ |
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beq 0b"
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/* The following part could be done in a C loop as well, but it needs
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to be assembler to save some cycles in the case where the optimized
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loop above finds the strings to be equal. */
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"\n\ |
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2:\n\ |
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ldrb r2, [%1, #0]\n\ |
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" PRELOADSTR("%1") "\n\ |
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" PRELOADSTR("%2") "\n\ |
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cmp r2, #0x0\n\ |
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beq 1f\n\ |
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ldrb r3, [%2, #0]\n\ |
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cmp r2, r3\n\ |
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bne 1f\n\ |
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0:\n\ |
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ldrb r3, [%1, #1]!\n\ |
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add %2, %2, #1\n\ |
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ands ip, r3, #0xff\n\ |
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beq 1f\n\ |
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ldrb r3, [%2]\n\ |
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cmp ip, r3\n\ |
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beq 0b\n\ |
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1:\n\ |
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ldrb lr, [%1, #0]\n\ |
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ldrb ip, [%2, #0]\n\ |
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rsb %0, ip, lr\n\ |
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3:\n\ |
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"
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: "=r" (result), "=&r" (s1), "=&r" (s2) |
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: "1" (s1), "2" (s2) |
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: "lr", "ip", "r2", "r3", "cc"); |
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return result; |
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}
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#endif
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while (*s1 != '\0' && *s1 == *s2) |
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{
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asm (PRELOADSTR("%0") : : "r" (s1)); |
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asm (PRELOADSTR("%0") : : "r" (s2)); |
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s1++; |
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s2++; |
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}
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out: |
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return (*(unsigned char *) s1) - (*(unsigned char *) s2); |
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}
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