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228 lines
3.6 KiB
228 lines
3.6 KiB
/* $Id: memcpy.S,v 1.3 2001/07/27 11:50:52 gniibe Exp $ |
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* |
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* "memcpy" implementation of SuperH |
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* |
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* Copyright (C) 1999 Niibe Yutaka |
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* |
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*/ |
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/* |
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* void *memcpy(void *dst, const void *src, size_t n); |
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* No overlap between the memory of DST and of SRC are assumed. |
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*/ |
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.globl _memcpy |
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.align 2 |
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_memcpy: |
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tst r6,r6 |
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bt/s 9f ! if n=0, do nothing |
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mov r4,r0 |
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sub r4,r5 ! From here, r5 has the distance to r0 |
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add r6,r0 ! From here, r0 points the end of copying point |
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mov #12,r1 |
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cmp/gt r6,r1 |
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bt/s 7f ! if it's too small, copy a byte at once |
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add #-1,r5 |
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add #1,r5 |
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! From here, r6 is free |
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! |
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! r4 --> [ ... ] DST [ ... ] SRC |
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! [ ... ] [ ... ] |
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! : : |
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! r0 --> [ ... ] r0+r5 --> [ ... ] |
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! |
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! |
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mov r5,r1 |
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mov #3,r2 |
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and r2,r1 |
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shll2 r1 |
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mov r0,r3 ! Save the value on R0 to R3 |
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mova jmptable,r0 |
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add r1,r0 |
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mov.l @r0,r1 |
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jmp @r1 |
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mov r3,r0 ! and back to R0 |
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.balign 4 |
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jmptable: |
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.long case0 |
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.long case1 |
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.long case2 |
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.long case3 |
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! copy a byte at once |
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7: mov r4,r2 |
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add #1,r2 |
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8: |
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cmp/hi r2,r0 |
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mov.b @(r0,r5),r1 |
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bt/s 8b ! while (r0>r2) |
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mov.b r1,@-r0 |
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9: |
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rts |
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nop |
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case0: |
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! |
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! GHIJ KLMN OPQR --> GHIJ KLMN OPQR |
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! |
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! First, align to long word boundary |
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mov r0,r3 |
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and r2,r3 |
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tst r3,r3 |
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bt/s 2f |
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add #-4,r5 |
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add #3,r5 |
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1: dt r3 |
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mov.b @(r0,r5),r1 |
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bf/s 1b |
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mov.b r1,@-r0 |
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! |
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add #-3,r5 |
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2: ! Second, copy a long word at once |
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mov r4,r2 |
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add #7,r2 |
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3: mov.l @(r0,r5),r1 |
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cmp/hi r2,r0 |
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bt/s 3b |
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mov.l r1,@-r0 |
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! |
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! Third, copy a byte at once, if necessary |
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cmp/eq r4,r0 |
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bt/s 9b |
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add #3,r5 |
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bra 8b |
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add #-6,r2 |
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case1: |
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! |
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! GHIJ KLMN OPQR --> ...G HIJK LMNO PQR. |
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! |
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! First, align to long word boundary |
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mov r0,r3 |
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and r2,r3 |
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tst r3,r3 |
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bt/s 2f |
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add #-1,r5 |
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1: dt r3 |
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mov.b @(r0,r5),r1 |
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bf/s 1b |
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mov.b r1,@-r0 |
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! |
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2: ! Second, read a long word and write a long word at once |
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mov.l @(r0,r5),r1 |
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add #-4,r5 |
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mov r4,r2 |
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add #7,r2 |
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! |
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#ifdef __LITTLE_ENDIAN__ |
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3: mov r1,r3 ! RQPO |
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shll16 r3 |
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shll8 r3 ! Oxxx |
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mov.l @(r0,r5),r1 ! NMLK |
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mov r1,r6 |
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shlr8 r6 ! xNML |
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or r6,r3 ! ONML |
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cmp/hi r2,r0 |
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bt/s 3b |
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mov.l r3,@-r0 |
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#else |
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3: mov r1,r3 ! OPQR |
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shlr16 r3 |
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shlr8 r3 ! xxxO |
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mov.l @(r0,r5),r1 ! KLMN |
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mov r1,r6 |
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shll8 r6 ! LMNx |
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or r6,r3 ! LMNO |
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cmp/hi r2,r0 |
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bt/s 3b |
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mov.l r3,@-r0 |
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#endif |
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! |
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! Third, copy a byte at once, if necessary |
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cmp/eq r4,r0 |
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bt/s 9b |
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add #4,r5 |
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bra 8b |
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add #-6,r2 |
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case2: |
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! |
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! GHIJ KLMN OPQR --> ..GH IJKL MNOP QR.. |
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! |
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! First, align to word boundary |
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tst #1,r0 |
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bt/s 2f |
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add #-1,r5 |
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mov.b @(r0,r5),r1 |
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mov.b r1,@-r0 |
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! |
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2: ! Second, read a word and write a word at once |
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add #-1,r5 |
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mov r4,r2 |
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add #3,r2 |
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! |
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3: mov.w @(r0,r5),r1 |
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cmp/hi r2,r0 |
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bt/s 3b |
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mov.w r1,@-r0 |
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! |
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! Third, copy a byte at once, if necessary |
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cmp/eq r4,r0 |
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bt/s 9b |
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add #1,r5 |
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mov.b @(r0,r5),r1 |
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rts |
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mov.b r1,@-r0 |
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case3: |
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! |
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! GHIJ KLMN OPQR --> .GHI JKLM NOPQ R... |
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! |
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! First, align to long word boundary |
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mov r0,r3 |
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and r2,r3 |
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tst r3,r3 |
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bt/s 2f |
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add #-1,r5 |
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1: dt r3 |
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mov.b @(r0,r5),r1 |
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bf/s 1b |
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mov.b r1,@-r0 |
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! |
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2: ! Second, read a long word and write a long word at once |
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add #-2,r5 |
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mov.l @(r0,r5),r1 |
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add #-4,r5 |
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mov r4,r2 |
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add #7,r2 |
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! |
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#ifdef __LITTLE_ENDIAN__ |
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3: mov r1,r3 ! RQPO |
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shll8 r3 ! QPOx |
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mov.l @(r0,r5),r1 ! NMLK |
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mov r1,r6 |
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shlr16 r6 |
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shlr8 r6 ! xxxN |
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or r6,r3 ! QPON |
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cmp/hi r2,r0 |
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bt/s 3b |
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mov.l r3,@-r0 |
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#else |
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3: mov r1,r3 ! OPQR |
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shlr8 r3 ! xOPQ |
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mov.l @(r0,r5),r1 ! KLMN |
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mov r1,r6 |
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shll16 r6 |
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shll8 r6 ! Nxxx |
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or r6,r3 ! NOPQ |
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cmp/hi r2,r0 |
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bt/s 3b |
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mov.l r3,@-r0 |
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#endif |
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! |
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! Third, copy a byte at once, if necessary |
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cmp/eq r4,r0 |
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bt/s 9b |
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add #6,r5 |
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bra 8b |
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add #-6,r2
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