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