diff options
Diffstat (limited to 'newlib/libc/machine/i960/strchr_ca.S')
| -rw-r--r-- | newlib/libc/machine/i960/strchr_ca.S | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/newlib/libc/machine/i960/strchr_ca.S b/newlib/libc/machine/i960/strchr_ca.S new file mode 100644 index 0000000..f52eae2 --- /dev/null +++ b/newlib/libc/machine/i960/strchr_ca.S @@ -0,0 +1,152 @@ +/******************************************************************************* + * + * 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 "strch_ca.s" +#ifdef __PIC + .pic +#endif +#ifdef __PID + .pid +#endif +/* + * (c) copyright 1988,1993 Intel Corp., all rights reserved + */ + +/* + procedure strchr (optimized assembler version for the CA) + + src_addr = strchr (src_addr, char) + + return a pointer to the first byte that contains the indicated + byte in the source string. Return null if the byte is not found. + + Undefined behavior will occur if the end of the source string (i.e. + the terminating null byte) is in the last two words of the program's + allocated memory space. This is so because, in several cases, strchr + will fetch ahead. Disallowing the fetch ahead would impose a severe + performance penalty. + + This program handles two cases: + + 1) the argument starts on a word boundary + 2) the argument doesn't start on a word boundary + + 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 src ptr; upon return it is a pointer to the matching byte, or null + g1 char to seek + g2 mask to avoid unimportant bytes in first word + g3 char to seek, broadcast to all four bytes + g4 word of the source string + g5 copy of the word + g6 extracted character + g7 byte extraction mask + g13 return address + g14 +*/ + + .globl _strchr + .globl __strchr + .leafproc _strchr, __strchr + .align 2 +_strchr: +#ifndef __PIC + lda Lrett,g14 +#else + lda Lrett-(.+8)(ip),g14 +#endif +__strchr: + + lda 0xff,g7 # byte extraction mask + and g1,g7,g1 # make char an 8-bit ordinal + shlo 8,g1,g2 # broadcast the char to four bytes + or g1,g2,g2 + shlo 16,g2,g4 + cmpo g1,g7 # is char being sought 0xff? + or g4,g2,g3 + lda (g14),g13 # preserve return address + notand g0,3,g5 # extract word addr of start of src + lda 0,g14 # conform to register linkage standard + and g0,3,g6 # extract byte offset of src + ld (g5),g4 # fetch word containing at least first byte + shlo 3,g6,g6 # get shift count for making mask for first word + lda 4(g5),g0 # post-increment src word pointer + subi 1,0,g5 # mask initially all ones +#if __i960_BIG_ENDIAN__ + shro g6,g5,g5 # get mask for bytes needed from first word +#else + shlo g6,g5,g5 # get mask for bytes needed from first word +#endif + notor g4,g5,g4 # set unneeded bytes to all ones + be.f Lsearch_for_0xff # branch if seeking 0xff + +Lsearch_for_word_with_char_or_null: + scanbyte g3,g4 # check for byte with char + lda (g4),g5 # copy word + ld (g0),g4 # fetch next word of src + bo.f Lsearch_for_char # branch if null found + scanbyte 0,g5 # check for null byte + lda 4(g0),g0 # post-increment src word pointer + bno.t Lsearch_for_word_with_char_or_null # branch if not null + +Lnot_found: + mov 0,g0 # char not found. Return null +Lexit_code: + bx (g13) # g0 = addr of char in src (or null); g14 = 0 +Lrett: + ret + +Lsearch_for_char: + subo 5,g0,g0 # back up the byte pointer +Lsearch_for_char.a: +#if __i960_BIG_ENDIAN__ + rotate 8,g5,g5 # shift word to position next byte +#endif + and g5,g7,g6 # extract byte + cmpo g1,g6 # is it char? + lda 1(g0),g0 # bump src byte ptr +#if ! __i960_BIG_ENDIAN__ + shro 8,g5,g5 # shift word to position next byte +#endif + be.f Lexit_code + cmpobne.t 0,g6,Lsearch_for_char.a # quit if null comes before char + b Lnot_found + +Lsearch_for_0xff: + lda 0xf0f0f0f0,g2 # make first comparison mask for char=-1 case. + or g5,g2,g2 + and g4,g2,g4 # make unimportant bytes of first word 0x0f + b Lsearch_for_word_with_char_or_null + +/* end of strchr */ + |