mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-11 19:49:32 +00:00
161 lines
5.7 KiB
ArmAsm
161 lines
5.7 KiB
ArmAsm
/*******************************************************************************
|
|
*
|
|
* Copyright (c) 1993 Intel Corporation
|
|
*
|
|
* Intel hereby grants you permission to copy, modify, and distribute this
|
|
* software and its documentation. Intel grants this permission provided
|
|
* that the above copyright notice appears in all copies and that both the
|
|
* copyright notice and this permission notice appear in supporting
|
|
* documentation. In addition, Intel grants this permission provided that
|
|
* you prominently mark as "not part of the original" any modifications
|
|
* made to this software or documentation, and that the name of Intel
|
|
* Corporation not be used in advertising or publicity pertaining to
|
|
* distribution of the software or the documentation without specific,
|
|
* written prior permission.
|
|
*
|
|
* Intel Corporation provides this AS IS, WITHOUT ANY WARRANTY, EXPRESS OR
|
|
* IMPLIED, INCLUDING, WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY
|
|
* OR FITNESS FOR A PARTICULAR PURPOSE. Intel makes no guarantee or
|
|
* representations regarding the use of, or the results of the use of,
|
|
* the software and documentation in terms of correctness, accuracy,
|
|
* reliability, currentness, or otherwise; and you rely on the software,
|
|
* documentation and results solely at your own risk.
|
|
*
|
|
* IN NO EVENT SHALL INTEL BE LIABLE FOR ANY LOSS OF USE, LOSS OF BUSINESS,
|
|
* LOSS OF PROFITS, INDIRECT, INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES
|
|
* OF ANY KIND. IN NO EVENT SHALL INTEL'S TOTAL LIABILITY EXCEED THE SUM
|
|
* PAID TO INTEL FOR THE PRODUCT LICENSED HEREUNDER.
|
|
*
|
|
******************************************************************************/
|
|
|
|
.file "memcpy.s"
|
|
#ifdef __PIC
|
|
.pic
|
|
#endif
|
|
#ifdef __PID
|
|
.pid
|
|
#endif
|
|
/*
|
|
* (c) copyright 1988,1993 Intel Corp., all rights reserved
|
|
*/
|
|
/*
|
|
procedure memmove (optimized assembler version for the 80960K series)
|
|
procedure memcpy (optimized assembler version for the 80960K series)
|
|
|
|
dest_addr = memmove (dest_addr, src_addr, len)
|
|
dest_addr = memcpy (dest_addr, src_addr, len)
|
|
|
|
copy len bytes pointed to by src_addr to the space pointed to by
|
|
dest_addr. Return the original dest_addr.
|
|
|
|
These routines will work even if the arrays overlap. The standard
|
|
requires this of memmove, but memcpy is allowed to fail if overlap
|
|
is present. Nevertheless, it is implemented the same as memmove
|
|
because the overhead is trifling.
|
|
|
|
Undefined behavior will occur if the end of the source array is in
|
|
the last two words of the program's allocated memory space. This
|
|
is so because the routine fetches ahead. Disallowing the fetch
|
|
ahead would impose a severe performance penalty.
|
|
|
|
Strategy:
|
|
|
|
Fetch the source array by words and store them by words to the
|
|
destination array, until there are fewer than three bytes left
|
|
to copy. Then, using the last word of the source (the one that
|
|
contains the remaining 0, 1, 2, or 3 bytes to be copied), store
|
|
a byte at a time until Ldone.
|
|
|
|
Tactics:
|
|
|
|
1) Do NOT try to fetch and store the words in a word aligned manner
|
|
because, in my judgement, the performance degradation experienced due
|
|
to non-aligned accesses does NOT outweigh the time and complexity added
|
|
by the preamble and convoluted body that would be necessary to assure
|
|
alignment. This is supported by the intuition that most source and
|
|
destination arrays (even more true of most big source arrays) will
|
|
be word aligned to begin with.
|
|
|
|
2) For non-overlapping arrays, rather than decrementing len to zero,
|
|
I calculate the address of the byte after the last byte of the
|
|
destination array, and quit when the destination byte pointer passes
|
|
that.
|
|
|
|
3) For overlapping arrays where the source starts at a lower address
|
|
than the destination the move is performed in reverse order.
|
|
|
|
4) Overlapping arrays where the source starts at a higher address
|
|
are treated like non-overlapping case. Where the two arrays exactly
|
|
coincide, the routine is short-circuited; no move is Ldone at all.
|
|
This costs only one cycle.
|
|
*/
|
|
|
|
.globl _memcpy, _memmove
|
|
.globl __memcpy, __memmove
|
|
.leafproc _memmove, __memmove
|
|
.leafproc _memcpy, __memcpy
|
|
.align 2
|
|
_memmove:
|
|
_memcpy:
|
|
#ifndef __PIC
|
|
lda Lrett,g14
|
|
#else
|
|
lda Lrett-(.+8)(ip),g14
|
|
#endif
|
|
__memmove:
|
|
__memcpy:
|
|
mov g14, g13 # preserve return address
|
|
cmpibge 0,g2,Lexit # exit if number of bytes to move is <= zero.
|
|
cmpo g0,g1 # does start of dest overlap end of src?
|
|
addo g2,g1,g3
|
|
be Lexit # no move necessary if src and dest are same
|
|
concmpo g3,g0
|
|
addo g2, g0, g6
|
|
bg Lbackwards # if overlap, then do move backwards
|
|
|
|
ld (g1), g7 # fetch first word of source
|
|
mov g0, g5
|
|
b Lwloop_b
|
|
|
|
Lwloop_a:
|
|
ld (g1), g7 # fetch ahead next word of source
|
|
st g4, (g5) # store word to dest
|
|
addo 4, g5, g5 # post-increment dest pointer
|
|
Lwloop_b: # word copying loop
|
|
addo 4, g1, g1 # pre-increment src pointer
|
|
cmpo g3, g1 # is len <= 3 ?
|
|
mov g7, g4 # keep a copy of the current word
|
|
bge Lwloop_a # loop if more than 3 bytes to move
|
|
cmpobe g6, g5, Lexit # quit if no more bytes to move
|
|
|
|
Lcloop_a: # character copying loop (len < 3)
|
|
stob g4, (g5) # store a byte
|
|
shro 8, g4, g4 # position next byte for storing
|
|
addo 1, g5, g5
|
|
cmpobne g6, g5, Lcloop_a # quit if no more bytes to move
|
|
|
|
Lexit:
|
|
mov 0, g14
|
|
bx (g13) # g0 = dest array address; g14 = 0
|
|
Lrett:
|
|
ret
|
|
|
|
Lwloop.a:
|
|
subo 4, g6, g6 # pre-decrement dest pointer
|
|
st g7, (g6) # store word to dest
|
|
Lbackwards: # word copying loop
|
|
subo 4, g3, g3 # pre-decrement src pointer
|
|
cmpo g1, g3 # is len <= 3?
|
|
ld (g3), g7 # fetch ahead next word of source
|
|
ble Lwloop.a # loop if more than 3 bytes to move
|
|
cmpobe g6, g0, Lexit # quit if no more bytes to move
|
|
|
|
Lcloop.a:
|
|
subo 1, g6, g6
|
|
rotate 8, g7, g7 # position byte for storing
|
|
stob g7, (g6) # store byte
|
|
cmpobne g6, g0, Lcloop.a # quit if no more bytes to move
|
|
b Lexit
|
|
|
|
/* end of memmove */
|