/******************************************************************************* * * 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 */