xtensa: fix memmove(), bcopy(), and memcpy().

- fix memmove to correctly handle overlapping src and dst;
- fix memcpy loop ending conditions from signed '<=' to '!=';
- modify bcopy to call memmove;

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
This commit is contained in:
Chris Zankel 2012-10-15 21:41:19 -07:00
parent c88d8df0cc
commit eae8a416af
1 changed files with 284 additions and 25 deletions

View File

@ -6,7 +6,7 @@
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2002 - 2005 Tensilica Inc.
* Copyright (C) 2002 - 2012 Tensilica Inc.
*/
#include <variant/core.h>
@ -27,14 +27,11 @@
#endif
.endm
/*
* void *memcpy(void *dst, const void *src, size_t len);
* void *memmove(void *dst, const void *src, size_t len);
* void *bcopy(const void *src, void *dst, size_t len);
*
* This function is intended to do the same thing as the standard
* library function memcpy() (or bcopy()) for most cases.
* library function memcpy() for most cases.
* However, where the source and/or destination references
* an instruction RAM or ROM or a data RAM or ROM, that
* source and/or destination will always be accessed with
@ -45,9 +42,6 @@
* !!!!!!! Handling of IRAM/IROM has not yet
* !!!!!!! been implemented.
*
* The bcopy version is provided here to avoid the overhead
* of an extra call, for callers that require this convention.
*
* The (general case) algorithm is as follows:
* If destination is unaligned, align it by conditionally
* copying 1 and 2 bytes.
@ -76,17 +70,6 @@
*/
.text
.align 4
.global bcopy
.type bcopy,@function
bcopy:
entry sp, 16 # minimal stack frame
# a2=src, a3=dst, a4=len
mov a5, a3 # copy dst so that a2 is return value
mov a3, a2
mov a2, a5
j .Lcommon # go to common code for memcpy+bcopy
/*
* Byte by byte copy
@ -107,7 +90,7 @@ bcopy:
s8i a6, a5, 0
addi a5, a5, 1
#if !XCHAL_HAVE_LOOPS
blt a3, a7, .Lnextbyte
bne a3, a7, .Lnextbyte # continue loop if $a3:src != $a7:src_end
#endif /* !XCHAL_HAVE_LOOPS */
.Lbytecopydone:
retw
@ -144,9 +127,6 @@ bcopy:
.global memcpy
.type memcpy,@function
memcpy:
.global memmove
.type memmove,@function
memmove:
entry sp, 16 # minimal stack frame
# a2/ dst, a3/ src, a4/ len
@ -182,7 +162,7 @@ memmove:
s32i a7, a5, 12
addi a5, a5, 16
#if !XCHAL_HAVE_LOOPS
blt a3, a8, .Loop1
bne a3, a8, .Loop1 # continue loop if a3:src != a8:src_end
#endif /* !XCHAL_HAVE_LOOPS */
.Loop1done:
bbci.l a4, 3, .L2
@ -260,7 +240,7 @@ memmove:
s32i a9, a5, 12
addi a5, a5, 16
#if !XCHAL_HAVE_LOOPS
blt a3, a10, .Loop2
bne a3, a10, .Loop2 # continue loop if a3:src != a10:src_end
#endif /* !XCHAL_HAVE_LOOPS */
.Loop2done:
bbci.l a4, 3, .L12
@ -305,6 +285,285 @@ memmove:
l8ui a6, a3, 0
s8i a6, a5, 0
retw
/*
* void bcopy(const void *src, void *dest, size_t n);
*/
.align 4
.global bcopy
.type bcopy,@function
bcopy:
entry sp, 16 # minimal stack frame
# a2=src, a3=dst, a4=len
mov a5, a3
mov a3, a2
mov a2, a5
j .Lmovecommon # go to common code for memmove+bcopy
/*
* void *memmove(void *dst, const void *src, size_t len);
*
* This function is intended to do the same thing as the standard
* library function memmove() for most cases.
* However, where the source and/or destination references
* an instruction RAM or ROM or a data RAM or ROM, that
* source and/or destination will always be accessed with
* 32-bit load and store instructions (as required for these
* types of devices).
*
* !!!!!!! XTFIXME:
* !!!!!!! Handling of IRAM/IROM has not yet
* !!!!!!! been implemented.
*
* The (general case) algorithm is as follows:
* If end of source doesn't overlap destination then use memcpy.
* Otherwise do memcpy backwards.
*
* Register use:
* a0/ return address
* a1/ stack pointer
* a2/ return value
* a3/ src
* a4/ length
* a5/ dst
* a6/ tmp
* a7/ tmp
* a8/ tmp
* a9/ tmp
* a10/ tmp
* a11/ tmp
*/
/*
* Byte by byte copy
*/
.align 4
.byte 0 # 1 mod 4 alignment for LOOPNEZ
# (0 mod 4 alignment for LBEG)
.Lbackbytecopy:
#if XCHAL_HAVE_LOOPS
loopnez a4, .Lbackbytecopydone
#else /* !XCHAL_HAVE_LOOPS */
beqz a4, .Lbackbytecopydone
sub a7, a3, a4 # a7 = start address for source
#endif /* !XCHAL_HAVE_LOOPS */
.Lbacknextbyte:
addi a3, a3, -1
l8ui a6, a3, 0
addi a5, a5, -1
s8i a6, a5, 0
#if !XCHAL_HAVE_LOOPS
bne a3, a7, .Lbacknextbyte # continue loop if
# $a3:src != $a7:src_start
#endif /* !XCHAL_HAVE_LOOPS */
.Lbackbytecopydone:
retw
/*
* Destination is unaligned
*/
.align 4
.Lbackdst1mod2: # dst is only byte aligned
_bltui a4, 7, .Lbackbytecopy # do short copies byte by byte
# copy 1 byte
addi a3, a3, -1
l8ui a6, a3, 0
addi a5, a5, -1
s8i a6, a5, 0
addi a4, a4, -1
_bbci.l a5, 1, .Lbackdstaligned # if dst is now aligned, then
# return to main algorithm
.Lbackdst2mod4: # dst 16-bit aligned
# copy 2 bytes
_bltui a4, 6, .Lbackbytecopy # do short copies byte by byte
addi a3, a3, -2
l8ui a6, a3, 0
l8ui a7, a3, 1
addi a5, a5, -2
s8i a6, a5, 0
s8i a7, a5, 1
addi a4, a4, -2
j .Lbackdstaligned # dst is now aligned,
# return to main algorithm
.align 4
.global memmove
.type memmove,@function
memmove:
entry sp, 16 # minimal stack frame
# a2/ dst, a3/ src, a4/ len
mov a5, a2 # copy dst so that a2 is return value
.Lmovecommon:
sub a6, a5, a3
bgeu a6, a4, .Lcommon
add a5, a5, a4
add a3, a3, a4
_bbsi.l a5, 0, .Lbackdst1mod2 # if dst is 1 mod 2
_bbsi.l a5, 1, .Lbackdst2mod4 # if dst is 2 mod 4
.Lbackdstaligned: # return here from .Lbackdst?mod? once dst is aligned
srli a7, a4, 4 # number of loop iterations with 16B
# per iteration
movi a8, 3 # if source is not aligned,
_bany a3, a8, .Lbacksrcunaligned # then use shifting copy
/*
* Destination and source are word-aligned, use word copy.
*/
# copy 16 bytes per iteration for word-aligned dst and word-aligned src
#if XCHAL_HAVE_LOOPS
loopnez a7, .backLoop1done
#else /* !XCHAL_HAVE_LOOPS */
beqz a7, .backLoop1done
slli a8, a7, 4
sub a8, a3, a8 # a8 = start of first 16B source chunk
#endif /* !XCHAL_HAVE_LOOPS */
.backLoop1:
addi a3, a3, -16
l32i a7, a3, 12
l32i a6, a3, 8
addi a5, a5, -16
s32i a7, a5, 12
l32i a7, a3, 4
s32i a6, a5, 8
l32i a6, a3, 0
s32i a7, a5, 4
s32i a6, a5, 0
#if !XCHAL_HAVE_LOOPS
bne a3, a8, .backLoop1 # continue loop if a3:src != a8:src_start
#endif /* !XCHAL_HAVE_LOOPS */
.backLoop1done:
bbci.l a4, 3, .Lback2
# copy 8 bytes
addi a3, a3, -8
l32i a6, a3, 0
l32i a7, a3, 4
addi a5, a5, -8
s32i a6, a5, 0
s32i a7, a5, 4
.Lback2:
bbsi.l a4, 2, .Lback3
bbsi.l a4, 1, .Lback4
bbsi.l a4, 0, .Lback5
retw
.Lback3:
# copy 4 bytes
addi a3, a3, -4
l32i a6, a3, 0
addi a5, a5, -4
s32i a6, a5, 0
bbsi.l a4, 1, .Lback4
bbsi.l a4, 0, .Lback5
retw
.Lback4:
# copy 2 bytes
addi a3, a3, -2
l16ui a6, a3, 0
addi a5, a5, -2
s16i a6, a5, 0
bbsi.l a4, 0, .Lback5
retw
.Lback5:
# copy 1 byte
addi a3, a3, -1
l8ui a6, a3, 0
addi a5, a5, -1
s8i a6, a5, 0
retw
/*
* Destination is aligned, Source is unaligned
*/
.align 4
.Lbacksrcunaligned:
_beqz a4, .Lbackdone # avoid loading anything for zero-length copies
# copy 16 bytes per iteration for word-aligned dst and unaligned src
ssa8 a3 # set shift amount from byte offset
#define SIM_CHECKS_ALIGNMENT 1 /* set to 1 when running on ISS with
* the lint or ferret client, or 0
* to save a few cycles */
#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
and a11, a3, a8 # save unalignment offset for below
sub a3, a3, a11 # align a3
#endif
l32i a6, a3, 0 # load first word
#if XCHAL_HAVE_LOOPS
loopnez a7, .backLoop2done
#else /* !XCHAL_HAVE_LOOPS */
beqz a7, .backLoop2done
slli a10, a7, 4
sub a10, a3, a10 # a10 = start of first 16B source chunk
#endif /* !XCHAL_HAVE_LOOPS */
.backLoop2:
addi a3, a3, -16
l32i a7, a3, 12
l32i a8, a3, 8
addi a5, a5, -16
src_b a6, a7, a6
s32i a6, a5, 12
l32i a9, a3, 4
src_b a7, a8, a7
s32i a7, a5, 8
l32i a6, a3, 0
src_b a8, a9, a8
s32i a8, a5, 4
src_b a9, a6, a9
s32i a9, a5, 0
#if !XCHAL_HAVE_LOOPS
bne a3, a10, .backLoop2 # continue loop if a3:src != a10:src_start
#endif /* !XCHAL_HAVE_LOOPS */
.backLoop2done:
bbci.l a4, 3, .Lback12
# copy 8 bytes
addi a3, a3, -8
l32i a7, a3, 4
l32i a8, a3, 0
addi a5, a5, -8
src_b a6, a7, a6
s32i a6, a5, 4
src_b a7, a8, a7
s32i a7, a5, 0
mov a6, a8
.Lback12:
bbci.l a4, 2, .Lback13
# copy 4 bytes
addi a3, a3, -4
l32i a7, a3, 0
addi a5, a5, -4
src_b a6, a7, a6
s32i a6, a5, 0
mov a6, a7
.Lback13:
#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
add a3, a3, a11 # readjust a3 with correct misalignment
#endif
bbsi.l a4, 1, .Lback14
bbsi.l a4, 0, .Lback15
.Lbackdone:
retw
.Lback14:
# copy 2 bytes
addi a3, a3, -2
l8ui a6, a3, 0
l8ui a7, a3, 1
addi a5, a5, -2
s8i a6, a5, 0
s8i a7, a5, 1
bbsi.l a4, 0, .Lback15
retw
.Lback15:
# copy 1 byte
addi a3, a3, -1
addi a5, a5, -1
l8ui a6, a3, 0
s8i a6, a5, 0
retw
/*
* Local Variables: