| /******************************************************************************* |
| * |
| * 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 "sncpy_ca.s" |
| #ifdef __PIC |
| .pic |
| #endif |
| #ifdef __PID |
| .pid |
| #endif |
| /* |
| * (c) copyright 1988,1993 Intel Corp., all rights reserved |
| */ |
| |
| /* |
| procedure strncpy (optimized assembler version for the CA) |
| |
| dest_addr = strncpy (dest_addr, src_addr, max_bytes) |
| |
| copy the null terminated string pointed to by src_addr to |
| the string space pointed to by dest_addr. Return the original |
| dest_addr. If the source string is shorter than max_bytes, |
| then null-pad the destination string. |
| |
| This routine 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. |
| |
| 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, strcpy |
| 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 original dest ptr; not modified, so that it may be returned. |
| g1 src ptr; shift count |
| g2 max_bytes |
| g3 src ptr (word aligned) |
| g4 dest ptr (word aligned) |
| g5 0xff -- byte extraction mask |
| 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 _strncpy |
| .globl __strncpy |
| .leafproc _strncpy, __strncpy |
| .align 2 |
| _strncpy: |
| #ifndef __PIC |
| lda Lrett,g14 |
| #else |
| lda Lrett-(.+8)(ip),g14 |
| #endif |
| __strncpy: |
| notand g1,3,g3 # extract word addr of start of src |
| lda (g14),g13 # preserve return address |
| cmpibge.f 0,g2,Lexit_code # Lexit if number of bytes to move is <= zero. |
| 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 |
| lda 0xff,g5 # load mask for byte extraction |
| subo 4,g4,g4 # store is pre-incrementing; back up dest addr |
| bne.f Lcase_3 # branch if dest not word aligned |
| |
| Lcase_1: # src and dest are word aligned |
| Lcase_1_wloop: # word copying loop |
| cmpi g2,4 # check for fewer than four bytes to move |
| lda (LSW),g1 # keep a copy of the src word |
| addo 4,g4,g4 # pre-increment dest addr |
| bl.f Lcase_1_cloop.a # branch if fewer than four bytes to copy |
| scanbyte 0,g1 # check for null byte in src word |
| ld (g3),LSW # pre-fetch next word of src |
| subi 4,g2,g2 # decrease max_byte count by the 4 bytes moved |
| bo.f Lcase_1_cloop.c # branch if word contains null byte |
| addo 4,g3,g3 # post-increment src addr |
| st g1,(g4) # store word in dest string |
| b Lcase_1_wloop |
| |
| Lcase_3_cloop.a: |
| Lcase_1_cloop.a: # character copying loop (max_bytes <= 3) |
| #if __i960_BIG_ENDIAN__ |
| rotate 8,g1,g1 # move next byte into position for extraction |
| #endif |
| and g5,g1,g14 # extract next char |
| Lcase_1_cloop.b: |
| cmpdeci 0,g2,g2 # is max_bytes exhausted? |
| be.f Lexit_code # Lexit if max_bytes is exhausted |
| cmpo 0,g14 # check for null byte |
| stob g14,(g4) # store the byte in dest |
| #if ! __i960_BIG_ENDIAN__ |
| shro 8,g1,g1 # move next byte into position for extraction |
| #endif |
| lda 1(g4),g4 # post-increment dest byte addr |
| bne.t Lcase_1_cloop.a # branch if null not reached |
| b Lcase_1_cloop.b |
| |
| Lexit_code: |
| mov 0,g14 # conform to register conventions |
| bx (g13) # g0 = addr of dest; g14 = 0 |
| Lrett: |
| ret |
| |
| Lcase_1_cloop.c: |
| Lcase_3_cloop.c: |
| #if __i960_BIG_ENDIAN__ |
| rotate 24,g5,g5 # move mask into position for testing next byte |
| #endif |
| and g5,g1,g14 # extract next char |
| cmpo 0,g14 # check for null byte |
| #if ! __i960_BIG_ENDIAN__ |
| lda (g5),LSW # keep a copy of the current mask |
| shlo 8,g5,g5 # move mask into position for testing next byte |
| #endif |
| bne.t Lcase_1_cloop.c # branch if null not reached |
| #if __i960_BIG_ENDIAN__ |
| subo 1,g5,g5 # null pad. |
| andnot g5,g1,g1 # last bytes to copy, and null pad rest of word |
| #else |
| subo 1,LSW,g5 # mask to get last bytes to copy, and null pad |
| and g5,g1,g1 # last bytes to copy, and null pad rest of word |
| #endif |
| st g1,(g4) |
| |
| Lcase_1_zwloop: # zero word loop |
| cmpi g2,4 # check for fewer than four bytes to move |
| addo 4,g4,g4 # pre-increment dest addr |
| bl.f Lcase_1_cloop.b # branch if fewer than four bytes to copy |
| subo 4,g2,g2 # decrease max_byte count by the 4 bytes moved |
| st g14,(g4) # store word in dest string |
| b Lcase_1_zwloop |
| |
| 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? |
| #if __i960_BIG_ENDIAN__ |
| shro 24,MSW,g5 # extract next char |
| #else |
| and g5,MSW,g5 # extract next char |
| #endif |
| be.f Lexit_code # Lexit if max_bytes is exhausted |
| cmpo 0,g5 # check for null byte |
| stob g5,(g1) # store the byte in dest |
| addo 1,g1,g1 # post-increment dest ptr |
| lda 0xff,g5 # re-initialize byte extraction mask |
| bne.t 1f # drop thru if null byte reached (to pad) |
| movl 0,g6 # blank out remainder of input buffer |
| 1: |
| cmpo g1,g4 # have we reached word boundary in dest yet? |
| #if __i960_BIG_ENDIAN__ |
| lda -8(g14),g14 # augment the shift counter |
| rotate 8,MSW,MSW # move next byte into position for extraction |
| #else |
| lda 8(g14),g14 # augment the shift counter |
| shro 8,MSW,MSW # move next byte into position for extraction |
| #endif |
| bne.t Lcase_3_cloop_at_start # branch if reached word boundary? |
| |
| ld (g3),MSW # fetch msw of operand for double shift |
| |
| Lcase_4: |
| |
| #if __i960_BIG_ENDIAN__ |
| cmpobne 0,g14,Lcase_3_wloop # branch if src is still unaligned. |
| |
| Lcase_3_wloop2: |
| cmpi g2,4 # less than four bytes to move? |
| lda (LSW),g1 # extract 4 bytes of src |
| lda 4(g3),g3 # post-increment src word addr |
| bl.f Lcase_3_cloop.a # branch if < four bytes left to move |
| scanbyte 0,g1 # check for null byte |
| lda (MSW),LSW # move msw to lsw |
| subi 4,g2,g2 # decrease max_byte count by the 4 bytes moved |
| ld (g3),MSW # pre-fetch msw of operand for double shift |
| bo.f Lcase_3_cloop.c # branch if word contains null byte |
| st g1,(g4) # store 4 bytes to dest |
| addo 4,g4,g4 # post-increment dest ptr |
| b Lcase_3_wloop2 |
| |
| #endif |
| |
| Lcase_3_wloop: |
| cmpi g2,4 # less than four bytes to move? |
| eshro g14,g6,g1 # extract 4 bytes of src |
| lda 4(g3),g3 # post-increment src word addr |
| bl.f Lcase_3_cloop.a # branch if < four bytes left to move |
| scanbyte 0,g1 # check for null byte |
| lda (MSW),LSW # move msw to lsw |
| subi 4,g2,g2 # decrease max_byte count by the 4 bytes moved |
| ld (g3),MSW # pre-fetch msw of operand for double shift |
| bo.f Lcase_3_cloop.c # branch if word contains null byte |
| st g1,(g4) # store 4 bytes to dest |
| addo 4,g4,g4 # post-increment dest ptr |
| b Lcase_3_wloop |
| |
| Lcase_245: |
| cmpo g0,g4 # check alignment of dest |
| ld (g3),MSW # pre-fetch second half |
| and 3,g1,g1 # compute shift count |
| lda 0xff,g5 # load mask for byte extraction |
| #if __i960_BIG_ENDIAN__ |
| subo g1,4,g14 # adjust shift count for big endian. |
| shlo 3,g14,g14 |
| #else |
| shlo 3,g1,g14 |
| #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 |
| /* than first word of source. */ |
| lda 4(g4),g4 # move dest word addr to first word boundary |
| eshro g14,g6,g5 # extract four bytes |
| lda (g0),g1 |
| bg.f 1f |
| mov MSW,LSW |
| lda 4(g3),g3 # move src word addr to second word boundary |
| 1: |
| mov g5,MSW |
| lda 0xff,g5 |
| b Lcase_25 |
| |
| /* end of strncpy */ |
| |