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[/] [openrisc/] [trunk/] [gnu-stable/] [newlib-1.18.0/] [newlib/] [libc/] [machine/] [xscale/] [memcmp.c] - Rev 816
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#if defined __thumb__ #include "../../string/memcmp.c" #else #include <string.h> #include "xscale.h" int memcmp (const void * s1, const void * s2, size_t len) { int result; asm ( #ifndef __OPTIMIZE_SIZE__ "\n\ cmp %2, #0x3 @ Is the length a multiple of four ?\n\ bls 6f @ no = goto SLOW CHECK\n\ and r2, %0, #0x3 @ get alignment of first pointer\n\ and r3, %1, #0x3 @ get alignment of second pointer\n\ cmp r2, r3 @ Do the two pointers share the same alignment ?\n\ bne 6f @ no = goto SLOW CHECK\n\ mov lr, %0 @ copy first pointer into LR\n\ mov r4, %1 @ copy second pointer into R4\n\ cmp r2, #0x0 @ Are we comparing word aligned pointers ?\n\ beq 3f @ yes = goto START WORD CHECK LOOP\n\ b 1f @ jump to LOOP TEST\n\ 0: @ LOOP START\n\ ldrb r2, [lr], #1 @ load byte from LR, post inc.\n\ " PRELOADSTR("lr") " @ preload\n\ ldrb r3, [r4], #1 @ load byte from R4, post inc.\n\ " PRELOADSTR("r4") " @ preload\n\ cmp r2, r3 @ are the two bytes the same ?\n\ bne 5f @ no = goto EXIT\n\ tst lr, #0x3 @ has the LR become word aligned ?\n\ bne 1f @ no = skip the next test\n\ cmp %2, #4 @ is the count >= 4 ?\n\ bhs 3f @ yes = goto START WORD CHECK LOOP\n\ 1: @ LOOP TEST\n\ sub %2, %2, #1 @ decrement count by one\n\ cmn %2, #0x1 @ has the count reached -1 ?\n\ bne 0b @ no = loop back to LOOP START\n\ b 4f @ goto PASS END\n\ \n\ 0: @ ??\n\ cmp %2, #0x7 @ Is the count a multiple of 8 ?\n\ bls 3f @ no = goto ???\n\ ldmia lr,{r2, r3} @ get two words from first pointer, post inc\n\ ldmia r4,{r5, r6} @ get two words from second pointer, post inc\n\ sub %2, %2, #0x4 @ decrement count by 4\n\ cmp r2, r5 @ has the count reached ????\n\ bne 1f @ no = goto\n\ sub %2, %2, #0x4 @ decrement the count by 4\n\ add lr, lr, #0x4 @ add 4 to first pointer\n\ add r4, r4, #0x4 @ add 4 to second pointer\n\ cmp r3, r6 @ ???\n\ beq 0b @ goto ???\n\ 1: @ ??\n\ add %2, %2, #0x4 @ Add four to count\n\ sub %0, lr, #0x4 @ decrement first pointer by 4\n\ sub %1, r4, #0x4 @ decrement second pointer by 4\n\ b 6f @ goto SLOW CHECK\n\ \n\ 3: @ START WORD CHECK LOOP\n\ cmp %2, #0x3 @ is the count <= 3 ?\n\ bls 1f @ yes = goto CHECK BYTES BY HAND\n\ ldr r2, [lr], #4 @ get word from LR, post inc\n\ ldr r3, [r4], #4 @ get word from R4, post inc\n\ sub %2, %2, #4 @ decrement count by 4\n\ cmp r2, r3 @ are the two words the same ?\n\ bne 1f @ no = goto CHECK WORD CONTENTS\n\ 0: @ WORD CHECK LOOP\n\ cmp %2, #0x3 @ is the count <= 3 ?\n\ bls 1f @ yes = goto CHECK BYTES BY HAND\n\ ldr r2, [lr], #4 @ load word from LR, post inc\n\ " PRELOADSTR("lr") " @ preload\n\ ldr r3, [r4], #4 @ load word from R4, post inc\n\ " PRELOADSTR("r4") " @ preload\n\ sub %2, %2, #4 @ decrement count by 4\n\ cmp r2, r3 @ are the two words the same ?\n\ beq 0b @ yes = goto WORD CHECK LOOP\n\ 1: @ CHECK BYTES BY HAND\n\ sub %0, lr, #0x4 @ move LR back a word and put into first pointer\n\ sub %1, r4, #0x4 @ move R4 back a word and put into second pointer\n\ add %2, %2, #4 @ increment the count by 4\n\ @ fall through into SLOW CHECK" #endif /* !__OPTIMIZE_SIZE__ */ "\n\ 6: @ SLOW CHECK\n\ sub %2, %2, #1 @ Decrement the count by one\n\ cmn %2, #0x1 @ Has the count reached -1 ?\n\ beq 4f @ Yes - we are finished, goto PASS END\n\ 0: @ LOOP1\n\ ldrb r2, [%0], #1 @ get byte from first pointer\n\ " PRELOADSTR("%0") " @ preload first pointer\n\ ldrb r3, [%1], #1 @ get byte from second pointer\n\ " PRELOADSTR("%1") " @ preload second pointer\n\ cmp r2, r3 @ compare the two loaded bytes\n\ bne 5f @ if they are not equal goto EXIT\n\ sub %2, %2, #1 @ decremented count by 1\n\ cmn %2, #0x1 @ has the count reached -1 ?\n\ bne 0b @ no = then go back to LOOP1\n\ 4: @ PASS END\n\ mov r3, r2 @ Default return value is 0\n\ 5: @ EXIT\n\ rsb %0, r3, r2 @ return difference between last two bytes loaded" : "=r" (result), "=&r" (s2), "=&r" (len) : "0" (s1), "1" (s2), "2" (len) : "r2", "r3", "r4", "r5", "r6", "cc", "lr"); return result; } #endif
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