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Retro68/gcc/newlib/libc/machine/i960/memcpy_ca.S
Wolfgang Thaller 1c3ad08d54 add libgloss and newlib 1.20.0 to gcc directory
2012-03-27 01:51:53 +02:00

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/*******************************************************************************
*
* 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 "memcp_ca.s"
#ifdef __PIC
.pic
#endif
#ifdef __PID
.pid
#endif
/*
* (c) copyright 1988,1992,1993 Intel Corp., all rights reserved
*/
/*
procedure memmove (optimized assembler version for the CA)
procedure memcpy (optimized assembler version for the CA)
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.
Memcpy will fail if the source and destination string overlap
(in particular, if the end of the source is overlapped by the
beginning of the destination). The behavior is undefined.
This is acceptable according to the draft C standard.
Memmove will not fail if overlap exists.
Undefined behavior will also occur if the end of the source string
(i.e. the terminating null byte) is in the last word of the program's
allocated memory space. This is so because, in several cases, the
routine will fetch ahead one word. Disallowing the fetch ahead would
impose a severe performance penalty.
This program handles five cases:
1) both arguments start on a word boundary
2) neither are word aligned, but they are offset by the same amount
3) source is word aligned, destination is not
4) destination is word aligned, source is not
5) neither is word aligned, and they are offset by differing amounts
At the time of this writing, only g0 thru g7 and g13 are available
for use in this leafproc; other registers would have to be saved and
restored. These nine registers, plus tricky use of g14 are sufficient
to implement the routine. The registers are used as follows:
g0 dest ptr; not modified, so that it may be returned
g1 src ptr; shift count
g2 len
g3 src ptr (word aligned)
g4 dest ptr (word aligned)
g5 -4 for Lbackwards move
Little endian
g6 lsw of double word for extraction of 4 bytes
g7 msw of double word for extraction of 4 bytes
Big endian
g6 msw of double word for extraction of 4 bytes
g7 lsw of double word for extraction of 4 bytes
g13 return address
g14 byte extracted.
*/
#if __i960_BIG_ENDIAN__
#define MSW g6
#define LSW g7
#else
#define LSW g6
#define MSW g7
#endif
.globl _memmove, _memcpy
.globl __memmove, __memcpy
.leafproc _memmove, __memmove
.leafproc _memcpy, __memcpy
.align 2
_memcpy:
_memmove:
#ifndef __PIC
lda Lrett,g14
#else
lda Lrett-(.+8)(ip),g14
#endif
__memcpy:
__memmove:
cmpibge.f 0,g2,Lquick_exit # Lexit if number of bytes to move is <= zero.
cmpo g0,g1 # if dest starts earlier than src ...
lda (g14),g13 # preserve return address
addo g2,g1,g5 # compute addr of byte after last byte of src
be.f Lexit_code # no move necessary if src and dest are same
concmpo g5,g0 # ... or if dest starts after end of src ...
notand g1,3,g3 # extract word addr of start of src
bg.f Lbackwards # ... then drop thru, else do move backwards
cmpo g3,g1 # check alignment of src
ld (g3),LSW # fetch word containing at least first byte
notand g0,3,g4 # extract word addr of start of dest
lda 4(g3),g3 # advance src word addr
bne.f Lcase_245 # branch if src is NOT word aligned
Lcase_13:
cmpo g0,g4 # check alignment of dest
subo 4,g4,g4 # store is pre-incrementing; back up dest addr
be.t Lcase_1 # branch if dest word aligned
Lcase_3: # src is word aligned; dest is not
addo 8,g4,g4 # move dest word ptr to first word boundary
lda (g0),g1 # copy dest byte ptr
mov LSW,MSW # make copy of first word of src
lda 32,g14 # initialize shift count to zero (mod 32)
Lcase_25:
Lcase_3_cloop_at_start: # character copying loop for start of dest str
cmpdeci 0,g2,g2 # is max_bytes exhausted?
be.f Lexit_code # Lexit if max_bytes is exhausted
#if __i960_BIG_ENDIAN__
rotate 8,MSW,MSW # move next byte into position for extraction
subo 8,g14,g14 # augment the shift counter
stob MSW,(g1) # store the byte in dest
#else
addo 8,g14,g14 # augment the shift counter
stob MSW,(g1) # store the byte in dest
shro 8,MSW,MSW # move next byte into position for extraction
#endif
lda 1(g1),g1 # post-increment dest ptr
cmpobne.t g1,g4,Lcase_3_cloop_at_start # branch if reached word boundary
ld (g3),MSW # fetch msw of operand for double shift
Lcase_4:
Lcase_3_wloop:
cmpi g2,4 # less than four bytes to move?
lda 4(g3),g3 # post-increment src word addr
eshro g14,g6,g1 # extract 4 bytes of src
bl.f Lcase_3_cloop # branch if < four bytes left to move
mov MSW,LSW # move msw to lsw
ld (g3),MSW # pre-fetch msw of operand for double shift
subi 4,g2,g2 # decrease max_byte count by the 4 bytes moved
st g1,(g4) # store 4 bytes to dest
addo 4,g4,g4 # post-increment dest ptr
b Lcase_3_wloop
Lcase_1_wloop: # word copying loop
subi 4,g2,g2 # decrease max_byte count by the 4 bytes moved
ld (g3),LSW # pre-fetch next word of src
addo 4,g3,g3 # post-increment src addr
st g1,(g4) # store word in dest string
Lcase_1: # src and dest are word aligned
cmpi g2,4 # check for fewer than four bytes to move
addo 4,g4,g4 # pre-increment dest addr
lda (LSW),g1 # keep a copy of the src word
bge.t Lcase_1_wloop # branch if at least four bytes to copy
Lcase_3_cloop:
cmpibe.f 0,g2,Lexit_code # Lexit if max_bytes is exhausted
Lcase_1_cloop:
#if __i960_BIG_ENDIAN__
rotate 8,g1,g1 # move next byte into position for extraction
#endif
subi 1,g2,g2
stob g1,(g4) # store the byte in dest
cmpi 0,g2
lda 1(g4),g4 # post-increment dest byte addr
#if ! __i960_BIG_ENDIAN__
shro 8,g1,g1 # move next byte into position for extraction
#endif
bne.t Lcase_1_cloop # Lexit if max_bytes is exhausted
Lexit_code:
mov 0,g14 # conform to register conventions
bx (g13) # g0 = addr of dest; g14 = 0
Lrett:
ret
Lcase_245:
cmpo g0,g4 # check alignment of dest
ld (g3),MSW # pre-fetch second half
and 3,g1,g1 # compute shift count
shlo 3,g1,g14
#if __i960_BIG_ENDIAN__
subo g14,0,g14 # adjust shift count for big endian
#endif
be.t Lcase_4 # branch if dest is word aligned
or g4,g1,g1 # is src earlier in word, later, or sync w/ dst
cmpo g0,g1 # < indicates first word of dest has more bytes
lda 4(g4),g4 # move dest word addr to first word boundary
eshro g14,g6,g5 # extract four bytes
lda (g0),g1
#if __i960_BIG_ENDIAN__
bge.f 1f
#else
bg.f 1f
#endif
mov MSW,LSW
lda 4(g3),g3 # move src word addr to second word boundary
1:
mov g5,MSW
b Lcase_25
Lbackwards:
notand g5,3,MSW # extract word addr of byte after end of src
cmpo MSW,g5 # check alignment of end of src
subo 4,MSW,g3 # retreat src word addr
addo g2,g0,g1 # compute addr of byte after end of dest
notand g1,3,g4 # extract word addr of start of dest
bne.f Lcase.245 # branch if src is NOT word aligned
Lcase.13:
cmpo g1,g4 # check alignment of dest
ld (g3),MSW # fetch last word of src
subo 4,g3,g3 # retreat src word addr
be.t Lcase.1 # branch if dest word aligned
Lcase.3: # src is word aligned; dest is not
mov MSW,LSW # make copy of first word of src
lda 32,g14 # initialize shift count to zero (mod 32)
Lcase.25:
Lcase.3_cloop_at_start: # character copying loop for start of dest str
cmpdeci 0,g2,g2 # is max.bytes exhausted?
be.f Lexit_code # Lexit if max_bytes is exhausted
#if ! __i960_BIG_ENDIAN__
rotate 8,LSW,LSW # move next byte into position for storing
#endif
lda -1(g1),g1 # pre-decrement dest ptr
cmpo g1,g4 # have we reached word boundary in dest yet?
stob LSW,(g1) # store the byte in dest
#if __i960_BIG_ENDIAN__
shro 8,LSW,LSW # move next byte into position for storing
addo 8,g14,g14 # augment the shift counter
#else
subo 8,g14,g14 # augment the shift counter
#endif
bne.t Lcase.3_cloop_at_start # branch if reached word boundary?
ld (g3),LSW # fetch lsw of operand for double shift
#if __i960_BIG_ENDIAN__
cmpobne 0,g14,Lcase.3_wloop
Lcase.3_wloop2:
cmpi g2,4 # less than four bytes to move?
lda -4(g3),g3 # post-decrement src word addr
mov MSW,g1 # extract 4 bytes of src
lda (LSW),MSW # move lsw to msw
subo 4,g4,g4 # pre-decrement dest ptr
bl.f Lcase.3_cloop # branch if < four bytes left to move
ld (g3),LSW # pre-fetch lsw of operand for double shift
subi 4,g2,g2 # decrease max.byte count by the 4 bytes moved
st g1,(g4) # store 4 bytes to dest
b Lcase.3_wloop2
#endif
Lcase.4:
Lcase.3_wloop:
cmpi g2,4 # less than four bytes to move?
lda -4(g3),g3 # post-decrement src word addr
eshro g14,g6,g1 # extract 4 bytes of src
lda (LSW),MSW # move lsw to msw
subo 4,g4,g4 # pre-decrement dest ptr
bl.f Lcase.3_cloop # branch if < four bytes left to move
ld (g3),LSW # pre-fetch lsw of operand for double shift
subi 4,g2,g2 # decrease max.byte count by the 4 bytes moved
st g1,(g4) # store 4 bytes to dest
b Lcase.3_wloop
Lcase.1_wloop: # word copying loop
subi 4,g2,g2 # decrease max.byte count by the 4 bytes moved
ld (g3),MSW # pre-fetch next word of src
subo 4,g3,g3 # post-decrement src addr
st g1,(g4) # store word in dest string
Lcase.1: # src and dest are word aligned
cmpi g2,4 # check for fewer than four bytes to move
subo 4,g4,g4 # pre-decrement dest addr
lda (MSW),g1 # keep a copy of the src word
bge.t Lcase.1_wloop # branch if at least four bytes to copy
Lcase.3_cloop:
cmpibe.f 0,g2,Lexit_code # Lexit if max_bytes is exhausted
#if ! __i960_BIG_ENDIAN__
rotate 8,g1,g1 # move next byte into position for storing
#endif
lda 4(g4),g4 # pre-decremented dest addr 4 too much
Lcase.1_cloop:
subi 1,g4,g4 # pre-decrement dest byte addr
cmpi g4,g0 # has dest ptr reached beginning of dest?
stob g1,(g4) # store the byte in dest
#if __i960_BIG_ENDIAN__
shro 8,g1,g1 # move next byte into position for storing
#else
rotate 8,g1,g1 # move next byte into position for storing
#endif
bne.t Lcase.1_cloop # Lexit if move is completed
b Lexit_code
Lcase.245:
cmpo g1,g4 # check alignment of dest
ld (MSW),MSW # pre-fetch word with at least last byte
and 3,g5,g5 # compute shift count
ld (g3),LSW # pre-fetch second to last word
shlo 3,g5,g14
#if __i960_BIG_ENDIAN__
subo g14,0,g14 # adjust shift count for big endian
#endif
be.t Lcase.4 # branch if dest is word aligned
or g4,g5,g5 # is src earlier in word, later, or sync w/ dst
cmpo g1,g5 # < indicates last word of dest has less bytes
eshro g14,g6,g5 # extract four bytes
bl.t 1f
mov LSW,MSW
#if ! __i960_BIG_ENDIAN__
be.t 1f
#endif
subo 4,g3,g3 # move src word addr to second word boundary
1:
mov g5,LSW
b Lcase.25
Lquick_exit:
mov g14,g13
b Lexit_code
/* end of memmove */
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