int result;
asm (
#ifndef __OPTIMIZE_SIZE__
-"
- cmp %2, #0x3 @ Is the length a multiple of four ?
- bls 6f @ no = goto SLOW CHECK
- and r2, %0, #0x3 @ get alignment of first pointer
- and r3, %1, #0x3 @ get alignment of second pointer
- cmp r2, r3 @ Do the two pointers share the same alignment ?
- bne 6f @ no = goto SLOW CHECK
- mov lr, %0 @ copy first pointer into LR
- mov r4, %1 @ copy second pointer into R4
- cmp r2, #0x0 @ Are we comparing word aligned pointers ?
- beq 3f @ yes = goto START WORD CHECK LOOP
- b 1f @ jump to LOOP TEST
-0: @ LOOP START
- ldrb r2, [lr], #1 @ load byte from LR, post inc.
-" PRELOADSTR("lr") " @ preload
- ldrb r3, [r4], #1 @ load byte from R4, post inc.
-" PRELOADSTR("r4") " @ preload
- cmp r2, r3 @ are the two bytes the same ?
- bne 5f @ no = goto EXIT
- tst lr, #0x3 @ has the LR become word aligned ?
- bne 1f @ no = skip the next test
- cmp %2, #4 @ is the count >= 4 ?
- bhs 3f @ yes = goto START WORD CHECK LOOP
-1: @ LOOP TEST
- sub %2, %2, #1 @ decrement count by one
- cmn %2, #0x1 @ has the count reached -1 ?
- bne 0b @ no = loop back to LOOP START
- b 4f @ goto PASS END
-
-0: @ ??
- cmp %2, #0x7 @ Is the count a multiple of 8 ?
- bls 3f @ no = goto ???
- ldmia lr,{r2, r3} @ get two words from first pointer, post inc
- ldmia r4,{r5, r6} @ get two words from second pointer, post inc
- sub %2, %2, #0x4 @ decrement count by 4
- cmp r2, r5 @ has the count reached ????
- bne 1f @ no = goto
- sub %2, %2, #0x4 @ decrement the count by 4
- add lr, lr, #0x4 @ add 4 to first pointer
- add r4, r4, #0x4 @ add 4 to second pointer
- cmp r3, r6 @ ???
- beq 0b @ goto ???
-1: @ ??
- add %2, %2, #0x4 @ Add four to count
- sub %0, lr, #0x4 @ decrement first pointer by 4
- sub %1, r4, #0x4 @ decrement second pointer by 4
- b 6f @ goto SLOW CHECK
-
-3: @ START WORD CHECK LOOP
- cmp %2, #0x3 @ is the count <= 3 ?
- bls 1f @ yes = goto CHECK BYTES BY HAND
- ldr r2, [lr], #4 @ get word from LR, post inc
- ldr r3, [r4], #4 @ get word from R4, post inc
- sub %2, %2, #4 @ decrement count by 4
- cmp r2, r3 @ are the two words the same ?
- bne 1f @ no = goto CHECK WORD CONTENTS
-0: @ WORD CHECK LOOP
- cmp %2, #0x3 @ is the count <= 3 ?
- bls 1f @ yes = goto CHECK BYTES BY HAND
- ldr r2, [lr], #4 @ load word from LR, post inc
-" PRELOADSTR("lr") " @ preload
- ldr r3, [r4], #4 @ load word from R4, post inc
-" PRELOADSTR("r4") " @ preload
- sub %2, %2, #4 @ decrement count by 4
- cmp r2, r3 @ are the two words the same ?
- beq 0b @ yes = goto WORD CHECK LOOP
-1: @ CHECK BYTES BY HAND
- sub %0, lr, #0x4 @ move LR back a word and put into first pointer
- sub %1, r4, #0x4 @ move R4 back a word and put into second pointer
- add %2, %2, #4 @ increment the count by 4
+"\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__ */
-"
-6: @ SLOW CHECK
- sub %2, %2, #1 @ Decrement the count by one
- cmn %2, #0x1 @ Has the count reached -1 ?
- beq 4f @ Yes - we are finished, goto PASS END
-0: @ LOOP1
- ldrb r2, [%0], #1 @ get byte from first pointer
-" PRELOADSTR("%0") " @ preload first pointer
- ldrb r3, [%1], #1 @ get byte from second pointer
-" PRELOADSTR("%1") " @ preload second pointer
- cmp r2, r3 @ compare the two loaded bytes
- bne 5f @ if they are not equal goto EXIT
- sub %2, %2, #1 @ decremented count by 1
- cmn %2, #0x1 @ has the count reached -1 ?
- bne 0b @ no = then go back to LOOP1
-4: @ PASS END
- mov r3, r2 @ Default return value is 0
-5: @ EXIT
+"\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)
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